Viessmann Viessmann AirflowPLUS System Technology Operating instructions

Installation, Service and
Operating Instructions
for use by heating contractor
Viessmann AirflowPLUS AH2A series
Hydronic forced air handler
Viessmann AirflowPLUS
Product may not be exactly as shown
IMPORTANT
Read and save these instructions
for future reference.
5680 011 - 24
07/2022
Please file in Service Binder
Safety
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Safety, Installation and Warranty Requirements
Please ensure that these instructions are read and understood before commencing installation. Failure to comply with
the instructions listed below and details printed in this manual can cause product/property damage, severe personal
injury, and/or loss of life. Ensure all requirements below are understood and fulfilled (including detailed information
found in manual subsections).
 For a listing of applicable literature,
please see section entitled “Important
Regulatory and Installation Requirements”.
Warranty
Information contained in this and related
product documentation must be read
and followed. Failure to do so renders
the warranty null and void.
Licensed professional heating contractor
The installation, adjustment, service and maintenance
of this equipment must be performed by a licensed
professional heating contractor.
 Please see section entitled
“Important Regulatory and Installation
Requirements”.
Advice to owner
Once the installation work is complete, the heating
contractor must familiarize the system operator/
ultimate owner with all equipment, as well as safety
precautions/requirements, shutdown procedure, and
the need for professional service annually before the
heating season begins.
WARNING
Follow the Viessmann maintenance schedule of the boiler
contained in this manual.
Operating and service documentation
It is recommended that all product documentation such as
parts lists, operating and service instructions be handed
over to the system user for storage. Documentation is to
be stored near air handler in a readily accessible location
for reference by service personnel.
2
Fiberglass wool materials
WARNING
Inhaling of fiberglass wool materials is a possible cancer
hazard. These materials can also cause respiratory, skin
and eye irritation.
The state of California has listed the airborne fibers of
these materials as a possible cancer hazard through
inhalation. When handling these materials, special care
must be applied.
Suppliers of fiberglass wool products recommend the
following precautions be taken when handling these
materials:
- Avoid breathing fiberglass dust and contact with
skin and eyes.
- Use NIOSH approved dust/mist respirator.
- Wear long-sleeved, loose fitting clothing, gloves
and eye protection.
- Wash work clothes separately from other clothing.
Rinse washer thoroughly.
- Operations such as sawing, blowing, tear-out and
spraying may generate airborne fiber concentration
requiring additional protection.
First aid measures
- If eye contact occurs, flush eyes with water to
remove dust. If symptoms persist, seek medical
attention.
- If skin contact occurs, wash affected areas gently
with soap and warm water after handling.
WARNING
Appliance materials of construction, may contain toxic
or harmful substances which can cause serious injury
or loss of life and which are known to the State of
California to cause cancer, birth defects and other
reproductive harm. Always use proper safety clothing,
respirators and equipment when servicing or working
nearby the appliance.
5680 011 - 24
Product documentation
Read all applicable documentation before commencing
installation. Store documentation near air handler in a
readily accessible location for reference in the future
by service personnel.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Table of Contents
5680 011 - 24
Page
Safety
Safety, Installation and Warranty Requirements..............2
Product documentation...........................................2
Warranty...............................................................2
Licensed professional heating contractor...................2
Advice to owner....................................................2
Operating and service documentation.......................2
Fiberglass wool materials........................................2
First aid measures..................................................2
General Information
About these Installation Instructions..............................5
Necessary Tools.........................................................5
Important Regulatory and Installation Requirements........6
Codes..................................................................6
Instructing the system user...................................6
Initial start-up........................................................6
Working on the equipment......................................6
Technical literature................................................6
Product Description
Introduction...............................................................7
Components................................................................7
Features......................................................................8
Equipment Selection and Sizing.....................................9
Compatibility Charts.....................................................9
Installation
Before Set-up..............................................................12
Minimum Clearances...................................................12
Dimensions.............................................................13
Heating Circuit Pumps.............................................14
Installation...............................................................14
Installation Examples.................................................15
Horizontal installation...........................................16
Vertical installation..............................................17
Proper Piping Practice................................................17
Connecting to the Heating System..............................17
Removing the Blower Shipping Bracket.......................18
Opening the Air Handling Unit....................................18
Panels.....................................................................19
Accessing the Connection Board................................22
Vitodens 100 B1HA/B1KA Wiring...............................23
Vitodens 100 B1HE, B1KE.........................................24
HO1B Wiring............................................................25
Vitodens 100 B2HE Wiring........................................26
Control Function.......................................................27
Supply Water Temperature (T1).................................27
Freeze Protection Temperature (T3)............................27
A/C Discharge Air Temperature (T4)...........................27
Remote Return Air Sensor (T5)..................................28
Ambient Sensor (T6).................................................28
Sensor Locations......................................................28
S1 Dip Switch Settings.............................................29
Door Safety Switch..................................................30
Electrical.................................................................31
Thermostat.........................................................31
Power Supply...........................................................32
Control Inputs.........................................................33
Setting Fan Speed....................................................34
3
Table of Contents
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Page
Startup
Quick Check.............................................................37
Pre-start Checklist.....................................................37
Startup Procedure....................................................38
Air handlers LED Indications for Temperature...............38
Installing Connection Board........................................39
Installing the Access Panels.......................................39
Operation
Indicators................................................................40
Flashing LED............................................................40
Normal Operation......................................................41
Heating mode.....................................................41
Cooling mode......................................................41
Summary............................................................41
External Heat Demand via Switching Contact Boilers equipped with HO1B User Interface..................41
Service
Illuminated Alarm Indicator.........................................42
Home freeze protect............................................42
Temperature sensor failure....................................42
Alarm Relay and LED Fault Codes..............................43
Control LED flash codes.......................................43
Alarm.................................................................43
Checking ECM (DC) Fan Motor Connections.................44
Troubleshooting.......................................................45
Service and Maintenance...........................................49
Checking temperature sensor................................49
Installed sensors..................................................49
Failed sensors......................................................49
Air filter..............................................................49
Circulator...........................................................49
Coils..................................................................49
4
System Layout 1......................................................50
System Layout 2......................................................51
System Layout 3......................................................52
System Layout 4......................................................53
System Layout 5......................................................54
System Layout 6......................................................55
System Layout 7......................................................56
System Layout 8......................................................57
System Layout 9......................................................58
System Layout 10....................................................59
Electrical Connectors.................................................60
Technical Data.........................................................62
Parts List.................................................................63
5680 011 - 24
Additional Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
General Information
About these Installation Instructions
Take note of all symbols and notations intended to draw attention to potential hazards or important
product information.
WARNING
Warnings draw your attention to the presence of potential
hazards or important product information.
CAUTION
Cautions draw your attention to the presence of potential
hazards or important product information.
Indicates an imminently hazardous situation which,
if not avoided, could result in death, serious injury or
substantial product/property damage.
Indicates an imminently hazardous situation which,
if not avoided, may result in minor injury or product/
property damage.
IMPORTANT
Helpful hints for installation, operation or maintenance
which pertain to the product.

This symbol indicates to note additional information
This symbol indicates that other instructions must be
referenced.
Necessary Tools
Testing/analysis equipment
(Use only calibrated equipment)
H Multimeter to measure 0 - 230V, 0 - 12A AC and
0-100 mA DC
H Manometer to measure air pressure 0 to 11 "w.c.
(accurately) (or a non-electric Magnehelic® manometer
may also be utilized)
Cleaning supplies
H Plastic hand brush
H Rags
Special items
5680 011 - 24
H Pipe joint sealant
5
General Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Important Regulatory and Installation Requirements
Codes
Working on the equipment
In Canada all electrical wiring is to be done in accordance
with the latest edition of CSA C22.1 Part 1 and/or local
codes. In the U.S. use the National Electrical Code ANSI/
NFPA 70. The heating contractor must also comply with
both the Standard for Controls and Safety Devices for
Automatically Fired Boilers, ANSI/ASME CSD-1, and
the Installation Code for Hydronic Heating Systems,
CSA B214-01, where required by the authority having
jurisdiction.
The installation, adjustment, service, and maintenance of
this air handler must be done by a licensed professional
heating contractor who is qualified and experienced in
the installation, service, and maintenance of hot water
heating equipment. There are no user serviceable parts
on the air handler.
Instructing the system user
For information regarding other Viessmann System
Technology componentry, please reference
documentation of the respective product.
The installer of the system is responsible to ensure the
system operator/ultimate owner is made familiar with the
system functioning, its activation, and its shut-down.
The following topics must be covered:
- Proper system operation sequence.
- Explain the equipment.
- Demonstrate an emergency shut-down, what to do
and what not.
- Explain that there is no substitute for proper
maintenance to help ensure safe operation.
Initial start-up
Initial start-up must be performed by a qualified heating
contractor. Proper completion of the Maintenance Record
by the heating contractor is also required.
Please carefully read this manual prior to attempting
start-up, maintenance or service. Any warranty is null
and void if these instructions are not followed.
We offer frequent installation and service seminars to
familiarize our partners with our products. Please inquire.
Ensure main power supply to equipment, the heating
system, and all external controls have been deactivated.
Take precautions in all instances to avoid accidental
activation of power during service work.
The completeness and functionality of field supplied
electrical controls and components must be verified by
the heating contractor. These include low water
cut-offs, flow switches (if used), staging controls,
pumps, motorized valves, air vents, thermostats, etc.
Technical literature
Literature for the Viessmann AirflowPLUS air handler:
- Technical Data Manual
- Installation, Service, and Operating Instructions
- Instructions of other Viessmann products utilized and
installed
- Installation codes mentioned in this manual
Leave all literature at the installation site and advise the
system operator/ultimate owner where the literature can
be found. Contact Viessmann for additional copies.
6
5680 011 - 24
This product comes with several safety instruction labels
attached.
Do not remove!
Contact Viessmann immediately if replacement labels are
required.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Product Description
Introduction
The Viessmann AirflowPLUS AH2A series air handlers
are to be used in conjunction with Viessmann boilers.
The automatic adjustments are made in heating as well
as cooling. This minimizes selecting an oversized heating
appliance just to accommodate the cooling load.
The Viessmann AirflowPLUS AH2A series is always the
right size.
Components
Cabinet
All cabinets have a tough, durable powder coat finish
on satin coat 20 gauge steel.
Heating coils
All heating coils are copper and assembled using no lead
solder. All coils and internal piping conform to ASTM
B-68, B-88 and/or B-743 standards.
High density aluminum fins provide maximum heat
transfer for small coil surface.
Fan and motor
The ECM fan is a wide body dynamically balanced for
extra quiet operation. Multi-directional sleeve bearing
motors allow mounting in any direction for maximum
installation flexibility.
Circulating pump
The internal circulating pump is matched for maximum
performance. All Airflow PLUS air handlers come with
internally mounted pumps for ease of installation.
5680 011 - 24
Legend
A Standard adaptors (at the rear)
B Heating coil and pump slide out for easy service
C Integrate pump with check valve
D Fibreglass insulation with reinforced foil face and
gasket seals
E Fan and controls slide out on rails
F Integrated filter rack
Check valve
A check valve is built into the circulator to protect against
backflow of water.
7
Product Description
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Features
Pump exercise function
If the internal circulating pump has not run in the previous
24 hours, the control will turn the pump on for 1 minute
to flush the lines and heat exchanger. This will help
ensure that the water lubricated pump does not seize
during long periods of inactivity.
Home freeze protection
The Viessmann AirflowPLUS AH2A series air handlers
have an integrated sensor which will help prevent the
home from freezing due to a faulty thermostat. Should
the ambient temperature get too low, the control will turn
the air handler on automatically and maintain the home
at approximately 40°F (4°C).
Note: this feature will only work if the boiler is turned on
and the air handler has power. While in Home
freeze protect mode the alarm relay and red light
will be on. Refer to page 42.
Status and alarm indicators
A bicolor LED indicator is installed in the air handler
housing and is used to indicate alarm, test mode, and
normal operation. The indicator will display temperature
readings of the sensors during normal operation.
Alarms
Should service problems arise the Viessmann AirflowPLUS
AH2A series will notify the user with a housing mounted
LED. Dry contacts are provided on the controller which
can be connected to an external device such as a warning
light or home security system.
8
5680 011 - 24
Customizing
The heating and cooling features can be field customized
to provide maximum comfort for almost any home or
location. Refer to page 28, 33, 34 and 35.
Product Description
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Equipment Selection and Sizing
Proper sizing of systems components is crucial for proper
operation;
1. Obtain room by room heat loss and/or heat gain
2. Determine heating water temperature
3. Determine duct layout
Make sure a proper room-by-room heat loss and heat
gain for the dwelling is calculated using Manual J, HRAI,
ASHRAE or other approved sizing method.
Compatibility Charts
Air handler model AH2A-213
Boiler supply water temperature
Vitodens 100 B1HA-94
Vitodens 100 B1HA-125
Vitodens 100 B1KA-125
120°F (28 MBH)



140°F (46 MBH)



160°F (62 MBH)



180°F (72 MBH)
----
Vitodens 100 B1HE-85
Vitodens 100 B1HE-120
Vitodens 100 B1HE-150
Vitodens 100 B1HE-199












-


Vitodens 100 B1KE-120
Vitodens 100 B1KE-199






-
Vitodens 222 B2TB-68
Vitodens 222 B2TB-125






-
Vitodens 200 B2HB-68
Vitodens 200 B2HB-94
Vitodens 200 B2HB-125
Vitodens 200 B2HB-160
Vitodens 200 B2HB-199
Vitodens 200 B2HA-285
Vitodens 200 B2HA-311
Vitodens 200 B2HA-352
Vitodens 200 B2HA-399
Vitodens 200 B2HA-530




















-








-








Vitodens 200 B2HE-85
Vitodens 200 B2HE-120
Vitodens 200 B2HE-150
Vitodens 200 B2HE-199












-


Vitocrossal 300 CU3A-94
Vitocrossal 300 CU3A-125
Vitocrossal 300 CU3A-160
Vitocrossal 300 CU3A-57, 199
















5680 011 - 24
Note: Compatibility charts do not take into consideration systems using additional heat emitters, DHW load etc.
Ensure the boiler selected meets all of the system requirements for loads generated by additional components.
It is the responsibility of the system designer to ensure proper sizing and equipment selection.
9
Product Description
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Compatibility Charts (continued)
Air handler model AH2A-354
Boiler supply water temperature
Vitodens 100 B1HA-94
Vitodens 100 B1HA-125
Vitodens 100 B1KA-125
120°F (44 MBH) 140°F (61 MBH) 160°F (83 MBH)









180°F (98 MBH)
----
Vitodens 100 B1HE-85
Vitodens 100 B1HE-120
Vitodens 100 B1HE-150
Vitodens 100 B1HE-199
Vitodens 100 B1KE-120
Vitodens 100 B1KE-199












-




-




Vitodens 222 B2TB-68
Vitodens 222 B2TB-125






-
Vitodens 200 B2HB-68
Vitodens 200 B2HB-94
Vitodens 200 B2HB-125
Vitodens 200 B2HB-160
Vitodens 200 B2HB-199
Vitodens 200 B2HA-285
Vitodens 200 B2HA-311
Vitodens 200 B2HA-352
Vitodens 200 B2HA-399
Vitodens 200 B2HA-530




















-








-








Vitodens 200 B2HE-85
Vitodens 200 B2HE-120
Vitodens 200 B2HE-150
Vitodens 200 B2HE-199








-


-


Vitocrossal 300 CU3A-94
Vitocrossal 300 CU3A-125
Vitocrossal 300 CU3A-160
Vitocrossal 300 CU3A-199















--
10
5680 011 - 24
Note: Compatibility charts do not take into consideration systems using additional heat emitters, DHW load etc.
Ensure the boiler selected meets all of the system requirements for loads generated by additional components.
It is the responsibility of the system designer to ensure proper sizing and equipment selection.
Product Description
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Compatibility Charts (continued)
Air handler model AH2A-385
Boiler supply water temperature
Vitodens 100 B1HA-94
Vitodens 100 B1HA-125
Vitodens 100 B1KA-125
120°F (51 MBH) 140°F (74 MBH)






160°F (90 MBH) 180°F (115 MBH)
-
-
-
Vitodens 100 B1HE-85
Vitodens 100 B1HE-120
Vitodens 100 B1HE-150
Vitodens 100 B1HE-199
Vitodens 100 B1KE-120
Vitodens 100 B1KE-199






-




-




--



Vitodens 222 B2TB-68
Vitodens 222 B2TB-125




-
-
Vitodens 200 B2HB-68
Vitodens 200 B2HB-94
Vitodens 200 B2HB-125
Vitodens 200 B2HB-160
Vitodens 200 B2HB-199
Vitodens 200 B2HA-285
Vitodens 200 B2HA-311
Vitodens 200 B2HA-352
Vitodens 200 B2HA-399
Vitodens 200 B2HA-530






























--







Vitodens 200 B2HE-85
Vitodens 200 B2HE-120
Vitodens 200 B2HE-150
Vitodens 200 B2HE-199




-


-


--

Vitocrossal 300 CU3A-94
Vitocrossal 300 CU3A-125
Vitocrossal 300 CU3A-160
Vitocrossal 300 CU3A-199








-


-


5680 011 - 24
Note: Compatibility charts do not take into consideration systems using additional heat emitters, DHW load etc.
Ensure the boiler selected meets all of the system requirements for loads generated by additional components.
It is the responsibility of the system designer to ensure proper sizing and equipment selection.
11
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Before Set-up
Before placing Viessmann AirflowPLUS in its installation
location, ensure all necessary accessories are installed.
CAUTION
The air handler must be installed in such a way that
electrical components are protected from water (spraying,
splashing, etc.) during operation and service.
Minimum Clearances
Horizontal Installation
Recommended minimum service clearances
For typical Viessmann AirflowPLUS installation, it
is recommended to install the air handler with the
clearances shown in the illustration.
a - 24 in. (610 mm)
b - 12 in. (305 mm)
These dimensions reflect the recommended service
clearance for the air handler only, ensure adequate clearance
is left for the installation of ducting, piping and electrical
connections. Only the b clearance may be reduced providing
there is enough clearance for ductwork, plumbing and
electrical connections, with zero clearance between the air
handler unit and ducting being acceptable.
12
5680 011 - 24
Vertical Installation
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Dimensions
IMPORTANT
The maximum ambient temperature must not exceed
104ºF (40ºC).
AH2A-213
AH2A-354
AH2A-385
a
in.
(mm)
22c
(578 mm)
23
(584 mm)
28
(711 mm)
b
in.
(mm)
18
(457 mm)
22
(559 mm)
22
(559 mm)
c*
in.
(mm)
32b
(826 mm)
34b
(876 mm)
34b
(876 mm)
d*
in.
(mm)
22a
(572 mm)
24e
(620 mm)
24e
(620 mm)
e*
in.
(mm)
23b
(597 mm)
25b
(650 mm)
25b
(650 mm)
f
in.
(mm)
2
(51 mm)
1c
(44 mm)
1c
(44 mm)
g
in.
(mm)
3
(76 mm)
3f
(92 mm)
3f
(92 mm)
h
in.
(mm)
24c
(629 mm)
25
(635 mm)
30
(762 mm)
Top view
* Using the adjustable levelling feet can add up to 1b in.
(38 mm) to the height of the air handler.
Legend
A Heating water supply connection
B Heating water return connection
5680 011 - 24
Front view
Side view
13
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Heating Circuit Pumps
Pump Model
Rated voltage
Rated current
Capacitor
Power consumption
Grundfos UPS15-58RU
VAC
Amp
F
Watts
115
0.74
10
87
Legend
A Speed 1 Pump curve
B Speed 2 Pump curve
C Speed 3 Pump curve
Note: All Viessmann AirflowPLUS air handlers come with
pump speed factory set to speed 3.
Installation
The contractor shall adhere to all local, state and national
code requirements pertaining to the installation of this
equipment.
The Viessmann AirflowPLUS AH2A can be suspended
by securing straps to the corners of the enclosure (field
supplied).
The Viessmann AirflowPLUS AH2A series air handler
can be mounted in most directions. Upflow, downflow,
horizontal left and horizontal right. You cannot install the
air handler on it’s back or suspended with front cover
facing down. An adequately sized drain pan and drain
connection must be installed under the appliance
if installed in or above a finished space.
Install the air handler with the door screwed in place to
avoid distortion of the cabinet. The installing contractor
must ensure that suspension materials are sized and
installed to provide sufficient support to the air handler
and connected accessory fittings and materials.
14
5680 011 - 24
If installed in an unfinished space, a drain pan is not
provided, necessary precautions must taken to ensure
proper drainage of water in the event of a water leak
(e.g. Floor drain, sump pump, moisture alarm...). This
appliance shall not be installed in a non conditioned space
where the potential may exist for the appliance and or
water lines and drain line to freeze.
Note: System layout examples are provided starting on
page 50 of these instructions.
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation Examples
Horizontal installation
Supply air
IMPORTANT
A field fabricated auxiliary drain pan with drain pipe is
recommended in all configurations.
Suspension material
(field supplied)
Secure the suspension
material to the corners
of the air handler housing.
CAUTION
Return air openings shall not be installed in back panel.
IMPORTANT
You cannot install the air handler on it’s back or
suspended with front cover facing down.
Return air
Note: Return air openings are provided in both the bottom
and side panels.
Note: Field selected suspension materials must be sized
by installing contractor so as to be of sufficient
strength to support air handler weight of 150 lbs.
(68 kg) and connected accessory fittings and
materials.
Temperature sensor and low voltage lead routing A/C
Coil installed upstream of Air Handler in return plenum.
Refer to “Remote Return Air Sensor T5” on page 27 for
information.
5680 011 - 24
For an installation over a finished space
A field fabricated auxiliary drain pan with drain pipe is
required to prevent damage by overflow due to blocked
condensate drain.
15
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation Examples (continued)
Vertical installation
The A/C coil is installed in the downstream air flow of the
Viessmann AirflowPLUS air handler.
Supply air
IMPORTANT
A field fabricated auxiliary drain pan with drain pipe is
required in all configurations.
CAUTION
Return air openings shall not be installed in back panel.
A/C coil
A Supply air temperature sensor lead shall be routed out of
air handler casing through knock-out provided in either
side of casing and secured to plenum using nylon clips
provided.
A
Return air
Drill 3/8 in. dia. hole in return air duct a minimum of
15 in. (381 mm) downstream of plenum.
Snap round bushing into hole and insert sensor lead
approximately 2 in. (51 mm) and secure to duct using
nylon strap included.
B
Air Filter
B Supply air temperature sensor lead and low voltage
lead wires shall be isolated from high voltage leads
and routed through knockouts provided.
Vertical installation
The A/C coil is installed in the upstream air flow of the
Viessmann AirflowPLUS air handler. This will require the
use of the remote return air temperature sensor mounted
upstream of the A/C coil. See page 27 for additional
information regarding the remote return air temperature
sensor.
Supply air
Supply air sensor lead and
low voltage lead wires shall
be isolated from high voltage
leads and routed through
knockouts provided.
16
Air Filter
A/C Coil
5680 011 - 24
Return air
For remote return air temperature
sensor drill 3/8 in. dia. hole in
return air duct a minimum of
15 in. upstream of plenum.
Snap round bushing into hole and
insert sensor lead approximately
2 in. (51 mm) and secure to duct
using nylon strap included.
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation Examples (continued)
Vertical installation
The A/C coil is installed in the downflow position of the
Viessmann AirflowPLUS air handler.
Return air
IMPORTANT
A field fabricated auxiliary drain pan with drain pipe is
required in all configurations.
CAUTION
Return air openings shall not be installed in back panel.
Air Filter
B
A Supply air temperature sensor lead shall be routed out of
air handler casing through knock-out provided in either
side of casing and secured to plenum using nylon clips
provided.
Drill 3/8 in. dia. hole in return air duct a minimum of
15 in. (381 mm) downstream of plenum.
Snap round bushing into hole and insert sensor lead
approximately 2 in. (51 mm) and secure to duct using
nylon strap included.
A/C coil
B Supply air temperature sensor lead and low voltage
lead wires shall be isolated from high voltage leads
and routed through knockouts provided.
A
Supply air
Proper Piping Practice
Support piping by proper suspension method.
Piping must not rest on or be supported by the air handler.
Use moderate amount of dope.
2 imperfect threads
This section constitutes an overview only! Refer to
subsequent sections for detailed information on individual
piping connections.
Leave 2 threads bare
Use an approved pipe sealant or teflon tape when
connecting the following installation fittings.
5680 011 - 24
Connecting to the Heating System
Air handler piping
Depending on the boiler selected and system design it may
be required to use a primary, secondary piping arrangement
to de-couple the flow through the boiler from the flow
through the air handler. Refer to the system layout examples
starting on page 50.
Duct work
All duct designs must be designed to conform with ARI
Manuals “J” and “D” or local codes and requirements.
To minimize fan noise in the living space, it is recommended
that the first six feet of supply and return air duct be lined
with acoustic insulation.
Boiler
Follow the instructions provided with the boiler for
installation and start-up of the boiler. Make sure the
heating device is turned off during air handler installation
and service. Ensure system has been filled, and all air
is purged from the system before turning on the heating
boiler.
Return and supply air duct work should be the same size
as the air handler openings up to the first branch, fitting or
transition.
17
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Removing the Blower Shipping Bracket
1. Remove the bracket retaining thumb screws and
discard.
2. Remove the bracket and discard.
Opening the Air Handler Unit
1. Remove the lower front panel retaining screws and set
aside.
2. Tilt the lower front panel forward at the top and lift
out.
3. Remove the upper front panel retaining screws and
set aside.
18
5680 011 - 24
4. Slide the upper front panel down and pull out.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation
Panels
There are 2 return air openings on the air handler. One
is located on the left side for vertical installations and
one is located at the bottom for horizontal installations.
For horizontal installations, remove the bottom panel and
install it to the left side panel opening.
Vertical opening
(left side)
Horizontal opening
(bottom)
Horizontal installation
1. Remove the bottom panel retaining screws and set
aside.
2. Remove the bottom panel and set aside.
Note: The fan tray is preinstalled into the bottom of
the air handler.
3. Install the bottom panel to the left side of the air
handler opening and secure with the retaining screws.
4. Connect the field supplied ducting to the bottom of
the air handler.
5680 011 - 24
5. Connect the field supplied ducting as required.
19
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Panels (continued)
To change the duct connection side of the air handler
for vertical installation, the right and left side panel can
be interchanged. To interchange the panels refer to the
following instructions.
1. Remove the retaining screws and set aside.
2. Remove the side panel by pulling up on the handle
and then out.
3. Remove the retaining screws from the panel on
the opposite side and set aside.
20
5680 011 - 24
4. Remove the side panel by pulling up on the handle
and then out.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation
Panels (continued)
5. Install the side panel (removed from step 2) by placing
the panel into the air handler and pushing down with
the handle.
6. Reinstall the retaining screws.
Note: To install the filter tray, see page 21.
7. Install the side panel (removed from step 4) by placing
the panel into the air handler and pushing down with
the handle.
5680 011 - 24
8. Reinstall the retaining screws.
21
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Panels (continued)
Filter tray for vertical installation
Note: If an A/C condenser is installed upstream, a field
supplied filter tray maybe placed elsewhere in the
ducting, see page 15.
1. Remove the retaining screws from the side panel.
2. Install the filter tray into the side panel opening.
3. Drill into the filter tray and secure the filter tray to the
side panel using the retaining screws.
4. Remove the 3 plastic retaining screws, open the tray
and remove the supplied filter.
5. Remove the side panel of the filter tray and insert the
filter.
6. Connect the field supplied ducting to the filter tray as
required.
Accessing the Connection Board
Accessing the connection board with hinged cover
1. Remove the blower assembly retaining screws and
set aside.
2. Slide the blower assembly forward.
IMPORTANT
Careful not to slide the blower assembly out too far,
it could put excessive strain on the cables.
3. Remove the 2 retaining screws from the connection
board cover.
4. Swing the cover up to open.
OR
Accessing the connection board with removable cover
1. Remove the blower assembly retaining screw and
set aside.
2. Slide the blower assembly forward.
IMPORTANT
Careful not to slide the blower assembly out too far,
it could put excessive strain on the cables.
3. Remove the retaining screw from the connection
board cover.
22
5680 011 - 24
4. Remove cover.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation
Vitodens 100 B1HA/B1KA Wiring
Viessmann AirflowPLUS
Connection Board
Thermostat
Vitodens 100 B1HA/B1KA
5680 011 - 24
For more details, refer to the Vitodens 100-W
Installation Instructions.
Connect call for heat (K2) relay of the air handler to the
OT connection (X21 terminals 1 and 2) of the Vitodens
100 B1HA/B1KA control.
23
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Vitodens 100 B1HE, B1KE
24
Connect call for heat (K2) relay of the air handler to the
96 connection of the Vitodens on the WP board.
5680 011 - 24
For more details, refer to the Vitodens 100-W
Installation Instructions.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation
HO1B Wiring
Viessmann AirflowPLUS
Connection Board
Thermostat
HO1B Connections
(Vitodens 200-W B2HA and B2HB
Vitodens 222-F B2TA and B2TB
Vitocrossal 300 CU3A)
5680 011 - 24
Refer to the appropriate boiler Installation
Instructions.
Connect call for heat (K2) relay of the air handler to
terminals DE1 of the integrated EA1 module. For coding
and programming requirements refer to page 40.
25
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
For more details, refer to the Vitodens 200-W
Installation Instructions.
26
Connect call for heat relay K2 of the air handler to the 96
connection of the WP board or zone inputs 1, 2 and 3 of
the MZ10 board.
5680 011 - 24
Vitodens 200 B2HE Wiring
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation
Control Function
Temperature sensors
The Viessmann AirflowPLUS integrated Control includes
five temperature sensors. Temperature sensors are 2-wire
devices that are connected to the control board with a
two pin connector allowing field replacement of individual
sensors.
Circulator
The circulator connection will support up to 5A 115VAC
pump motors, activated by control logic on call for heat.
Air conditioning relay (24VAC)
The Air Conditioning relay is on when the A/C cooling
function should be active. It is a 24VAC signal that will
energize the A/C power contactor.
Fan relay (24VAC 5A Max dry contact)
The fan relay is on at any time the fan is running. The
relay presents a contact closure that may be used to
activate external air cleaners, humidifiers, etc that should
be active while the fan is running.
Heat relay (24VAC 5A Max dry contact)
The heat relay is on when the thermostat calls for heat.
Alarm relay (24VAC 5A Max dry contact)
The alarm relay provides a dry contact closure that is used
to indicate an alarm condition. The contacts are closed
during an alarm condition.
The alarm relay contacts may be used to activate an
external device to alert the user that an alarm condition
exists.
Alarm conditions include:
• Heat exchanger freeze protection limit exceeded
• Return air temperature is too low
Supply Water Temperature (T1)
The sensor is mounted at the supply side of the water
heating coil.
Freeze Protection Temperature (T3)
The sensor will be mounted above the hydronic heat
exchanger to detect freezing temperatures from the
A/C heat exchanger that could damage the water heat
exchanger. The supply air is also monitored during the
cooling mode.
A/C Discharge Air Temperature (T4)
5680 011 - 24
The sensor is installed in the supply air path of the
Air Handler, downstream of the air handler and/or air
conditioning assembly. Refer to pages 14 and 15.
27
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Remote Return Air Sensor (T5)
Remote return air sensor installation
Note: If the A/C coil is installed in the return air plenum.
• The remote return air sensor must be installed.
This sensor is then inserted into the return air duct at
a location approximately 15 in. (380 mm) upstream of
the A/C coil. (Pages 14 and 15)
• Set dip switches as per the system preference.
The remote return air sensor is preinstalled within the
Viessmann AirflowPLUS cabinet complete with a 10 ft.
(3 m) cable lead for remote sensor locations. Remove
the strap from the sensor lead and install in the required
location.
Ambient Sensor (T6)
It should be noted that this is a precautionary measure
and is not designed to prevent water line freezing in
situations where the ambient temperatures may get too
low.
The ambient sensor provides air handler operation
when ambient temperatures outside of the air handler
cabinet are less than 40°F (4°C). When the temperature
rises above 41°F (5°C) the system will resume normal
operation.
The sensor connector is plugged onto the control board
and routed through the cabinet fan tray openings up to
the top panel.
Sensor Locations
28
5680 011 - 24
Legend
A Supply water temperature
B Ambient temperature
C Return air temperature
D Supply air temperature
E Remote air temperature (not shown)
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
S1 Dip Switch Settings
Dip switches S2 (in the image below) are shown in the
factory setting.
Note: The black squares represent the switch positions.
Dip switch settings
The dip switch will allow the selection of custom setup
options. Refer to Variable Table for system options.
Maximum heating override
The return air temperature will be monitored for
unreasonably high values. When the upper limit is reached
the unit will override the thermostat and maintain the
temperature at the set value.
Minimum cooling override
The return air temperature will be monitored for
unreasonably low values. When the lower limit is reached
the unit will override the thermostat and maintain the
temperature at the set value.
IMPORTANT
Start-up: Do not power the unit until the water supply
has been connected and the system purged of air. The
circulating pump may come on at anytime. Dry operation
of the pump will damage the pump and void warranty.
Note: To access the connections board see pages 17 and 21.
Dip Switch S1 Maximum heating override
Dip Switch S1 Minimum cooling override
90°F (32°C)
12
65°F (18°C)
34
85°F (29.5°C)
12
68°F (20°C)
34
80°F (26.5°C)
12
70°F (21°C)
34
75°F (24°C)
12
Note: Power to the Viessmann AirflowPLUS air handler must
be turned off before changing switch settings.
Note: Factory settings are shown in the grey areas of both
charts.
72°F (22°C)
34
System select dip switch settings
Four system settings are available. Two for use when the
evaporator is in the supply air stream, two for use when
the evaporator is in the discharge air stream. In each
configuration, the hot water threshold of 85°F or 110°F
(29°C or 43°C) may be selected, this ensures that only
warm air is available during heating operations.
Dip Switch S1 System Settings
Evaporator in Supply Air / 110°F (43°C)
5678
Evaporator in Return Air / 110°F (43°C)
5678
5680 011 - 24
Evaporator in Supply Air / 85°F (29°C)
5678
Evaporator in Return Air / 85°F (29°C)
5678
29
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Door Safety Switch
30
5680 011 - 24
The door safety switch is located on the internal center
support panel. Once the lower front panel is removed,
the switch will disconnect power to the control board
and fan motor.
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Electrical
Thermostat
Most standard heat/cool, setback, or electronic thermostats
are compatible with the Viessmann AirflowPLUS AH2A
series air handlers.
Thermostat wire from the thermostat is connected to the
screw terminals located on the control board inside the
air handler. They should be connected as follows:
RH, RC – power (24VAC)
W – heating
Y – cooling (if present)
G – continuous run fan (if present on thermostat)
Note: During continuous fan operation, the fan speed will
operate at 40% of the set cooling speed.
IMPORTANT
A/C condenser must be connected to position “AC relay
-Y-C” only. Improper connections will result in loss of
protection functions.
24VAC COM
24VAC
Fan Speed
Stage 2 Cool
Stage 1 Cool
Stage 1 Heat
Viessmann AirflowPLUS
Connection Board
5680 011 - 24
Single stage thermostat
field supplied (typical)
Dry Contacts
A/C Relay Heat
Fan
Alarm
Note: Before making the connection to the thermostat for
a two stage cooling function, remove the jumper
across terminals Y1 and Y2 on the Viessmann
AirflowPLUS connection board.
31
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Power Supply
WARNING
WARNING
If system components are not grounded, serious injury
from electric current can result if an electrical fault
occurs.
Connect the appliance and pipework to the
equipotential bonding of the building in question.
Power connections L and N are not interchangeable.
Main power supply
120VAC, 1Ph, 60Hz, 12A
Main
Disconnect
Switch
WARNING
Incorrectly executed electrical installations can lead to
injuries from electrical current and result in appliance
damage.
External Connections
Internal Connections
>
Power Connection
Terminal
Door Safety
Switch
AC Line
Viessmann AirflowPLUS
Connection Board
PMP
XFO
XFI
ECM
Power
32
5680 011 - 24
ECM
Control
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Installation
Control Inputs
Heating control
A 24VAC input is provided to control the heating
function. When the thermostat calls for heat 24VAC
is applied to the W contact and a heating cycle will be
initiated.
Note: the heating cycle control will be ignored while a
cooling cycle is in progress.
If the heating control is turned off during the initial heat
exchanger warm up or during the fan cycle up to speed
the heat mode will be terminated with a short run period
for the fan prior to shutting down.
When thermostat changes off to on:
Initially pump speed is active, Fan is off. Provide time for
heating coil to warm up. After 15 sec. the fan will active at
normal operating speed as set up by the selected dip switch
settings. See setting fan speed pages 33, 34 and 35.
Cooling control
A 24VAC input is provided to control the cooling function.
When the thermostat calls for cooling 24VAC is applied
to the Y contact and a cooling cycle will be initiated.
Note: the heating cycle control will be ignored while a
cooling cycle is in progress.
If the cooling control is turned off during the fan cycle up
to speed period the cool mode will be terminated without
an end of cycle fan period.
5680 011 - 24
Thermostat fan on/auto control
The 24VAC Thermostat Fan On/Auto input will select the
fan operation. When the thermostat is in the Auto state
the fan will be off while not heating/cooling. In the fan ON
position, 24V is applied to the G contact and the fan will
run at the lowest speed while not heating/cooling. During
a heating cycle the fan is always off during the initial heat
exchanger warm up period.
33
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Setting Fan Speed
Dip switches S2 (in the image below) are shown in the
factory setting.
Note: The black squares represent the switch positions.
AH2A-213 Viessmann AirflowPLUS Air Handler
1/3 hp ECM - air flow selectable options
Example:
12345678
This example shows the factory setting with a heating fan
speed of 1155 CFM (Nominal+10%) a cooling fan speed
of 1290 CFM (Nominal+10%) and the cooling fan speed
profile see chart below for delay.
Both the heating and cooling fan speeds must be selected
from dip switch S2 adjustment (Nominal+10%, Nominal
or Nominal -10%).
Note: To access the connections board see pages 17 and 21.
Legend
H Heat
A Adjustment
C Cooling
D Delay
Dip Switch S2 Heating fan speed
Dip Switch S2
Adjustment
Dip Switch S2 Cooling fan speed
12
12
12
12
Nominal
3 4 +10%
1155 CFM
910 CFM
740 CFM
605 CFM
Nominal
1050 CFM
825 CFM
675 CFM
Nominal
-10%
924 CFM
726 CFM
594 CFM
34
34
Dip Switch S2
Delay
56
56
56
56
1290 CFM 1010 CFM
825 CFM
660 CFM
550 CFM
1175 CFM
925 CFM
750 CFM
600 CFM
484 CFM
1034 CFM
814 CFM
660 CFM
528 CFM
Dip Switch S2 Cooling Fan Speed Profiles
Pre-Run
Time
Motor
percent
Short Run
Time
Motor
percent
Motor OFF
Time
Motor
percent
5 min.
82%
2 min.
88%
2 min.
75%
3 min.
82%
2 min.
88%
2 min.
75%
2 min.
82%
--
--
4 min.
75%
--
--
--
--
4 min.
75%
78
78
78
Note: for two stage cooling the first sage (Y1) is approximately 65% of maximum speed, a fan only call is approximately
40% of cool speed.
Note: Power to the Viessmann AirflowPLUS air handler must be turned off before changing switch settings.
The above values are approximations only, actual results may vary.
Note: Factory settings are shown in the grey areas in the charts above.
34
5680 011 - 24
78
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Setting Fan Speed (continued)
Dip switches S2 (in the image below) are shown in the
factory setting.
Note: The black squares represent the switch positions.
AH2A-354 Viessmann AirflowPLUS Air Handler
1/2 hp ECM - Air Flow Selectable Options
Example:
12345678
This example shows the factory setting with a heating fan
speed of 1430 CFM (Nominal+10%) a cooling fan speed
of 1804 CFM (Nominal+10%) and the cooling fan speed
profile see chart below for delay.
Both heating and cooling fan speeds must be selected
from dip switch S2 adjustment (Nominal+10%, Nominal
or Nominal -10%).
Note: To access the connections board see pages 17 and 21.
Legend
H Heat
A Adjustment
C Cooling
D Delay
Dip Switch S2 Heating fan speed
Dip Switch S2
Adjustment
12
12
1430 CFM 1050 CFM
830 CFM
830 CFM
Nominal
1300 CFM
980 CFM
760 CFM
5760 CFM 1640 CFM 1270 CFM
980 CFM
740 CFM
Nominal
-10%
1140 CFM
860 CFM
660 CFM
660 CFM
860 CFM
650 CFM
Nominal
3 4 +10%
34
34
Dip Switch S2
Delay
12
12
Dip Switch S2 Cooling fan speed
56
56
56
1804 CFM 1400 CFM 1050 CFM
1440 CFM 1100 CFM
56
800 CFM
Dip Switch S2 Cooling Fan Speed Profiles
Pre-Run
Time
Motor
percent
Short Run
Time
Motor
percent
Motor OFF
Time
Motor
percent
5 min.
82%
2 min.
88%
2 min.
75%
3 min.
82%
2 min.
88%
2 min.
75%
2 min.
82%
--
--
4 min.
75%
--
--
--
--
4 min.
75%
78
78
78
5680 011 - 24
78
Note: for two stage cooling the first sage (Y1) is approximately 65% of maximum speed, a fan only call is approximately
40% of cool speed.
Note: Power to the Viessmann AirflowPLUS air handler must be turned off before changing switch settings.
The above values are approximations only, actual results may vary.
Note: Factory settings are shown in the grey areas in the charts above.
35
Installation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Setting Fan Speed (continued)
Dip switches S2 (in the image below) are shown in the
factory setting.
Note: The black squares represent the switch positions.
AH2A-385 Viessmann AirflowPLUS Air Handler
3/4 hp ECM - Air Flow Selectable Options
Example:
12345678
This example shows the factory setting with a heating fan
speed of 1800 CFM (Nominal+10%) a cooling fan speed
of 2060 CFM (Nominal+10%) and the cooling fan speed
profile see chart below for delay.
Both heating and cooling fan speeds must be selected
from dip switch S2 adjustment (Nominal+10%, Nominal
or Nominal -10%).
Note: To access the connections board see pages 17 and 21.
Legend
H Heat
A Adjustment
C Cooling
D Delay
Dip Switch S2 Heating fan speed
Dip Switch S2
Adjustment
12
12
12
Dip Switch S2 Cooling fan speed
12
56
56
56
56
Nominal
3 4 +10%
1800 CFM 1750 CFM 1620 CFM 1450 CFM 2060 CFM 1900 CFM 1780 CFM 1650 CFM
Nominal
1650 CFM 1590 CFM 1470 CFM 1320 CFM 1875 CFM 1730 CFM 1620 CFM 1500 CFM
Nominal
-10%
1480 CFM 1430 CFM 1320 CFM 1180 CFM 1680 CFM 1560 CFM 1450 CFM 1350 CFM
34
34
Dip Switch S2
Delay
Dip Switch S2 Cooling Fan Speed Profiles
Pre-Run
Time
Motor
percent
Short Run
Time
Motor
percent
Motor OFF
Time
Motor
percent
5 min.
82%
2 min.
88%
2 min.
75%
3 min.
82%
2 min.
88%
2 min.
75%
2 min.
82%
--
--
4 min.
75%
--
--
--
--
4 min.
75%
78
78
78
Note: for two stage cooling the first sage (Y1) is approximately 65% of maximum speed, a fan only call is approximately
40% of cool speed.
Note: Power to the Viessmann AirflowPLUS air handler must be turned off before changing switch settings.
The above values are approximations only, actual results may vary.
Note: Factory settings are shown in the grey areas in the charts above.
36
5680 011 - 24
78
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Startup
Quick Check
WARNING
This appliance is not intended for installation in a
non conditioned space where the potential may exist
for the water and or drain lines to freeze.
1. Is the purge valve installed on the return line from the
air handler upstream from the isolation valve?
2. Is the air handler hung and isolated to avoid
transmitting vibration through framing and duct work?
3. Full port isolation valves MUST be provided.
Restrictive valves will limit performance.
4. Is outdoor cooling unit contactor wired to
screw terminals on controller to provide hard-start
protection?
5. Are thermostat connections correct, including cooling
and continuous run connections?
6. Have the packing materials been removed from the
blower and the pump?
7. Is there an installation manual for the home owner?
8. Is the unit accessible? Are there clearances for service
and component replacement?
9. Is the supply air temperature stream sensor mounted
downstream of the cooling coil?
10. Is the remote return air sensor installed upstream of
the A/C coil if the A/C coil is in the return air duct?
Refer to page 16.
11. Are the supply air plenum and return duct/drop
acoustically lined? [at least 6 ft. (1.8 m)] of the return
duct/drop must be lined in addition to the supply
plenum).
12. Is the filter cover in place? Is a clean filter in place?
Is the supplied filter rack installed?
13. If this appliance is installed with air conditioning, the
A/C refrigerant charge and system operation must be
verified by a certified/ licensed mechanic prior to
commissioning.
Pre-start Checklist
1)  REMOVE PACKING MATERIALS FROM LEFT SIDE OF BLOWER
2)  ONLY IN HORIZONTAL CONFIGURATIONS REMOVE THE PACKING IN THE WATER LINE.
3)  BLEED ALL AIR FROM WATER LINES
4)  BLEED AIR FROM END OF CIRCULATOR AT SLOTTED BLEED SCREW GENTLY OPEN BLEED SCREW ABOUT
1/2 TURN UNTIL AIR BLEEDS OUT ENSURE WATER DOES NOT LEAK ONTO CONTROL BOARD IN FAN
COMPARTMENT
5)  DISCHARGE AIR SENSOR INSTALLED DOWNSTREAM OF A/C COIL WHEN A/C COIL INSTALLED IN SUPPLY
DUCT DOWNSTREAM OF AIR HANDLER. REFER TO INSTALLATION INSTRUCTIONS.
OR
 REMOTE RETURN AIR SENSOR INSTALLED UPSTREAM OF A/C COIL
IF COIL IS INSTALLED IN RETURN AIR DUCT, UPSTREAM OF AIR HANDLER.
OR
 IF A/C COIL IS INSTALLED IN RETURN AIR DUCT UPSTREAM OF AIR HANDLER,
AIR FILTER IS INSTALLED UPSTREAM OF A/C COIL
6)  INITIATE CALL FOR HEAT,
 PUMP TURNS ON
 FAN TURNS ON
7)  DISCONNECT POWER TO OUTDOOR CONDENSER. INITIATE CALL FOR COOLING, ONCE FAN IS
RUNNING, CONFIRM 24 VOLT OUTPUT AT Y AND C AT COM RELAY ON MAIN CONTROL.
RECONNECT POWER IF TEST SUCCESSFUL
5680 011 - 24
8)  CANCEL CALL FOR COOLING APPROXIMATELY 1 MINUTE LATER, FAN TURNS OFF
37
Startup
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Startup Procedure
Do not start the air handler or BOILER until ALL Air has
been purged from water lines and air handler pump!
1. Fill the boiler loop with water, but do not start it.
5. Start the boiler according to the instructions provided
with the boiler. Set the design water temperature and
wait for the system to shut off.
2. Purge all air from the heating boiler.
6. Turn on the power to the air handler and set the room
thermostat for heat to energize the fan and pump.
If a gurgling sound is present, it should subside within
one minute. If noise is still present after one minute,
repeat step 3 to purge air as necessary.
3. Purge all air from the space-heating loop by closing the
isolation valve on the return leg of the loop and open
the drain to purge air. Open the return leg isolation
valve and then close the drain valve.
4. When there is no bleed screw, we recommend running
on high speed #3 for approximately b to 1 minute.
If this does not work and you can still hear a
‘swooshing/swirling’ at the pump, then attempt to
pulse the air out of the pump by going back and forth
between high speed and low speed, 10 seconds on
each speed for about 1 minute and that should
eliminate the air within the pump.
7. Check supply and return pipes for temperature
differences to make sure there is flow. There should
be a noticeable difference in temperature between
supply and return lines.
Air Handler LED Indications for Temperature
Temperature for 5 sensors
The Air Handler allows the attachment of up to five
sensors.
The LED sequence for displaying five sensors uses a
bicolor LED to indicate the sensor number followed by the
sensor temperature reading. The sequence starts with a
one red blink to indicate sensor T1, this is followed by
the temperature indication using green blinks as described
above. This is followed by a 2-blink red LED indication
for system select. This is followed by a 3 blink red LED
indication for sensor T3. This is followed by the T3
temperature reading using green blinks. This continues up
to 6 red blinks indicating the reading for sensor T6. After
a short delay sequence begins again with 1 red blink.
For example, if sensor T1 is reading 59°F (15°C) and
sensor T3 is reading 75°F (24°C) the sequence will start
with 1 red blink (sensor T1), 1 green blink, 5 green blinks,
2 red blinks (sensor T3), 2 green blinks, 4 green blinks.
The sequence will continue to indicate the temperature,
or status, of sensor T4 through T6.
First Series of
Red Flash(es)
Normal temperature indication
The LED will blink to indicate temperatures between
32°F and 176°F (0°C and 80°C). When the temperature
is below 32°F (0°C) it will indicate 0°C. When the
temperature is above 176°F (80°C) it will indicate 80°C.
Refer to page 38 for fahrenheit conversion.
The temperature is indicated by blinking the most
significant digit followed by the least significant digit. If
the temperature is 79°F (26°C) the led will blink 2 times,
short delay, then 6 times.
When the least significant digit of the temperature is
32°F (0°C), the blink indication will substitute 1. If the
temperature is 86°F (30°C) the LED will blink 3-1, if it is
122°F (50°C) it will blink 5-1.
If the temperature is between 32°F and 48°F (0°C and
9°C), the LED will blink only the least significant digit,
that is, if the temperature is 43°F (6°C) the LED will only
blink 6 times. If the temperature is 32°F (0°C), a 1 will
be substituted, and the LED will blink 1 time.
Sensor
Second Series of
Red Flash(es)
1 1 sec. pause
T1 Heating Coil Inlet Water
Temperature
3
T3 Heating Coil Freeze
Protection Temperature
First digit of
temperature
reading
4
T4 Supply Air Temperature
5
T5 Return Air Temperature
6
T6 Ambient Air Temperature
Green Flash(es)
1 sec. pause Second digit of
temperature
reading
38
5680 011 - 24
Example: 3 Red followed by 5 green is 35°C
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Startup
Installing Connection Board
Installing connection board with hinged cover
1. Close connection board cover.
2. Secure cover with the retaining screws.
3. Slide in blower assembly.
4. Reinstall retaining screw.
OR
Installing connection board with removable cover
1. Install the connection board cover.
2. Secure cover with retaining screw.
3. Slide in blower assembly.
4. Reinstall retaining screw.
Installing the Access Panels
1. Set the top of the upper front cover in place and
slide up.
2. Reinstall retaining screws.
3. Set the bottom of the lower front panel in place and
slide up.
5680 011 - 24
4. Reinstall retaining screws.
39
Operation
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Indicators
A bicolor LED is used as a system status indicator to
indicate alarm, test mode, normal operation, etc.
The indicator will display the temperature sensor values
during normal operation. When abnormal behavior is
noted the LED will display an indication to indicate the
condition.
Flashing LED
°F = °C x 1.8 + 32
e.g. 24 x 1.8 + 32 = 75.2°F
During normal operating mode the LED will blink to
indicate the temperature reading of the five sensors.
The LED will blink RED to indicate the sensor number.
It will then blink the temperature in GREEN.
All temperature readings are in Celsius. Example, while
sensor T3 is reading 75°F (24°C) the LED will blink
RED 3X then GREEN 2X then GREEN 4X then RED 4X
followed by the reading for the next sensor, see LED chart
on page 37.
LED flash code will indicate the sensor location in RED
and temperature in GREEN.
e.g. 3RED then 2GREEN, pause, 4GREEN = Sensor T3 is
75°F (24°C)
• An 8RED then 8RED flash indicates a bad reading or
defective sensor, this may repeat several cycles.
Note: If a defective sensor is present, the audible alarm
will sound. For corrective action refer to
troubleshooting.
Sensor 1 should see GREEN flashes of 4GREEN – 3GREEN
110°F (43°C) to 8GREEN –2GREEN 180°F (82°C)
depending on the temperature of the hot water source.
With 120°F (49°C) to 180°F (82°C) entering water
the reading would be 3GREEN – 6GREEN 97°F (36°C)
to 7GREEN – 1GREEN 160°F (71°C), after the correct
number of red flashes to indicate the sensor #.
Refer to page 26 and 27 for sensor numbers and
description.
40
5680 011 - 24
Anytime a fault condition exist, the specific fault condition
will be displayed represented by a specific LED flash code
(refer to page 43) approximately 2 seconds after the
display of temperature reading for temperature sensor T6.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Operation
Normal Operation
Heating mode
On a call for heat from the thermostat, the circulating
pump will turn on. Giving the pump 15 sec. to heat the
coil, the fan will activate heating the home until the
thermostat is satisfied.
Once the thermostat is satisfied, the circulating pump
will shut down and fan will continue to run for 2 min.
During the heating cycle the hot water temperature is
monitored. If the hot water temperature drops below
a threshold the fan will be turned off. The hot water
temperature continues to be monitored after the fan
is shut off. When the temperature rises to 10°F (6°C)
above the selected threshold the fan will be restarted.
The threshold may be set according to the system select
switch. The threshold may be set at 110°F or 85°F
(43°C or 29°C)
Cooling mode
On a call for cooling from the thermostat, if the fan is on,
it will turn off and the A/C relay will be energized. The
outdoor condenser will turn on and flood the evaporator
coil with refrigerant. The fan will turn on and deliver cool
air to the system. After approximately 5 min. (this gives
the condenser and coil time to normalize pressures), the
microprocessor control will cause multiple fan speed
adjustments in order to target the latent load first
(humidity) before speeding up to capture the sensible
load. Sensor feedback allows this enhanced blower
fan feature to protect the outdoor unit from refrigerant
slugging caused by lower fan speeds, dirty filters, poor
duct design or poor installations.
Summary
In heating mode, most error codes and/or improper
unit operation are caused by too low of supply water
temperature or sensors not installed correctly. Cooling
mode errors are caused by too low or too high of
refrigerant charge or gross over sizing of equipment.
External Heat Demand via Switching Contact - Boilers equipped with HO1B User Interface
Contact closed:
5680 011 - 24
Set address 3A to 3A:2, for external demand upon
closure of DE1.
• The burner is switched ON subject to load. The boiler
heats to the set boiler water temperature selected in
coding “9b” in the “General” group.
Limiting the boiler water temperature by means of the
set boiler water temperature and the electronic
maximum limit of the boiler water temperature
(coding “06” in the “Combustion Controller” group)
41
Service
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Illuminated Alarm Indicator
• All Viessmann AirflowPLUS AH2A series air handlers
are equipped with a housing mounted Illuminated alarm
indicator. This indicator light illuminates any time the
control mounted alarm relay is activated.
• The control mounted alarm relay is turned on under
the following circumstances.
1) Home freeze protect
Automatic Home Freeze Protection is initiated when the
ambient air temperature reads lower than 40°F (4°C).
During this time the alarm relay and heat cycle are turned
on until the ambient temperature rises above 54°F (12°C).
2) Temperature sensor failure
If a sensor has a bad read, or is malfunctioning, the LED
will blink RED 8X-8X rather than the green temperature
reading. This 8X blink may repeat. Be sure to cycle
through all sensors at least three times to determine is
a sensor is faulty.
42
5680 011 - 24
Legend
A Ambient air temperature sensor
B Indicator light
Service
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Alarm Relay and LED Fault Codes
Control LED flash codes
A visual display is provided by the housing mounted LED.
This display advises of the current status of the air handler
behavior and its environment should unusual conditions
exist. Refer to the chart below. When multiple flash codes
are being displayed, they will be displayed in the following
order:
Flash Code
RRR
RRG
RGG
Explanation
Cooling Lockout
Freeze protect cycle in process
Low ambient temperature
Cause
Page 42
Page 42
Page 42
R = Red
G = Green
Alarm Buzzer
Sounding
RED LED Sensor
Indication
YES
Followed
by:
Alarm
Alarm Relay is on when an unusual condition is detected.
The connector is a two terminal connector that provides
a contact closure when the Alarm Relay is on.
It can be silenced again by turning power to the unit off
and on. An alarm condition does not mean the unit is
not working, it just means the information the control is
receiving does not meet specifications. These conditions
could be cool supply water, supply air temperature too
cold, room air too cold, etc.
The alarm will shut off when the condition is corrected.
Note: There must be 1 sensor on all inputs in the proper
locations. If A/C coil is in the return air plenum then
the return MUST be installed on the board at the
RETURN AIR receptacle with the sensor lead
end located 15 in. (381 mm) upstream of the A/C
coil in the return air duct.
The supply air sensor (supplied) shall be
installed downstream of the heating coil in
the supply air ductwork and attached to the
SUPPLY AIR receptacle location on the
control.
Refer to pages 26 and 27 for detailed sensor information.
LED
Flash Code
Reason
3 flashes
(Freeze Sensor)
7 green flashes,
then 7 green flashes
Water coil Freeze Sensor temperature
or Supply Air Sensor limit exceeded –
inadequate air flow, A/C locked on.
YES
4 flashes
(Supply Air Sensor)
7 green flashes,
then 7 green flashes
Water coil Freeze Sensor temperature
or Supply Air Sensor limit exceeded –
inadequate air flow, A/C locked on.
YES
1, 3, 4, 5 or 6
flashes
8 red flashes,
then 8 red flashes
Temperature Sensor misread,
wait for next indication.
YES
1, 3, 4, 5 or 6
flashes
8 red flashes,
then 8 red flashes
Failed Temperature Sensor.
Replace.
5680 011 - 24
Temperature Sensor RED LED Flash Code Identification
1 Flashes Water In Temperature Sensor
3 Flashes Water Coil Freeze Temperature Sensor
4 Flashes Supply Air Temperature Sensor
5 Flashes Return Air Sensor
6 Flashes Ambient Temperature Sensor
43
Service
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Checking ECM (DC) Fan Motor Connections
Note: The fan motor operates independent of the
controller temperature control logic. Externally
installed temperature sensors operate as system
safeties only.
ECM Motor Control
Connector
(female)
Control
(male)
44
5680 011 - 24
Pin number
1 Common C1
2 W/W1
3 Common C2
4 Delay tap select
5 Cool tap select
6 Y1
7 Adjust tap select
8 Output 9 Return (reversing) valve (heat pump only)
10 Humidistat (BK)
11 Heat tap select
12 24VAC (R)
13 2nd stage heat (EM/W2)
14 2nd stage cool (Y/Y2)
15 Fan (G)
16 Output +
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Service
Troubleshooting
Power is on at the air handler.
Yes
Air handler ambient air sensor
is activated by a temperature,
less than 40°F (4°C).
Yes
The red light is illuminated
on the housing.
Yes
The internal pump and
circulation fan is running.
Yes
The air handler is in home freeze
protect mode. Once return air
exceeds 45°F (7°C), pump, fan
and red light will turn off.
Pump does not run
Often, closing the isolation valve on the return leg and
opening the drain port so that water flows through the
pump can free the pump. For the integrated Grundfos
pumps, remove the screw-on cover from the face of
the pump, and rotate the shaft one turn with a slotted
screwdriver.
If either method fails to free the pump, removal for cleaning
or replacement is necessary. The pump exercise function
will help prevent pump seizing.
Pump is noisy at start-up
Air is present in heating loop. If sound has not diminished
within 1 minute, purge air in accordance with the Start-Up
procedures.
Insufficient or no heat
- Plugged air filter or coil. Refer to Maintenance section
for filter care and coil cleaning.
- Air in heating loop; purge system.
- Inlet and outlet connections to air handler backwards;
reverse connections.
- Supply water temperature set too low or not calibrated
properly; check water temperature.
- Restriction in heating loop; remove restrictions, check
valves stick, valves too restrictive, left partially closed
after purging or closed valve (no or improper flow).
Fan runs for cooling but not for heating
Room thermostat may be connected improperly.
Heating during standby mode
Probable cause is thermal Siphoning. See check valve
description for details; repair or replace check valve.
5680 011 - 24
Home freeze protection
This sequence is initiated by extreme low air temperatures
[less than 40°F (4°C)] and are detected by the ambient
air temperature sensor.
45
Service
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Troubleshooting (continued)
Water coil freeze protection
This sequence is initiated by extreme low air temperatures
crossing over the freeze protection sensor located directly
above the air handler water coil.
The air handler internal water coil
freeze sensor T3 is activated
by low air temperature.
Yes
Housing mounted LED
is illuminated.
Yes
Yes
The air handler internal water coil
freeze sensor T3 is activated
by low air temperature.
Continue
46
Yes
Refer to cooling lockout chart.
5680 011 - 24
Check for poor air flow,
restrictions, plugged filters,
low refrigerant charge
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Service
Troubleshooting (continued)
Cooling lockout
This feature is initiated if three freeze protect cycles occur
within a single cooling cycle or, if three freeze cycles
occur when a cooling cycle is not in progress.
A freeze protect cycle is when the air handler integral A/C
coil freeze sensor is triggered by unacceptably low supply
air temperatures.
Power is on at the air handler.
Yes
The air handler internal water coil
freeze sensor is activated by three
extreme low temperature cycles.
Yes
The red light is illuminated
on the housing.
Yes
Observe each sensor code and
record related flash codes as
shown on the housing mounted
LED. Refer to page 43.
Yes
Sensor T3 flash code indicates
7 green then 7 green.
Yes
5680 011 - 24
Inadequate air flow, plugged filter,
extreme ESP, low refrigerant.
No
Outdoor ambient or
thermostat set too low.
47
Service
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Troubleshooting (continued)
Temperature sensor failure identification
Temperature sensor failure is identified by viewing the
housing mounted LED.
Power is on at the air handler
for more than 24 hours.
Yes
No
The red housing mounted
LED is illuminated after
5 minutes of power on.
Yes
The housing mounted LED will
flash an error code. Record
colors and number of flashes
(5 cycles/min). Refer to chart
on page 43 for identification.
Continue
48
5680 011 - 24
If 8 red flashes followed by
8 red flashes repeats after
a specific sensor, then
replace that sensor.
Service
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Service and Maintenance
Resistance in k Ohms
Checking temperature sensor
1.
Remove cables from temperature sensor.
2.
Check the sensor resistance and compare the actual
values with the curve in the chart.
3.
Replace sensor in case of severe deviation.
Temperature sensors
Uninstalled sensors
Systems may elect to not use one, or more, of the five
sensors. In this case, the absent sensor temperature is
replaced by one long green blink following the red sensor
number blinks.
Failed Sensors
When a sensor is incorrectly installed or defective, the
LED indication will substitute red 8-8 for a normal
temperature reading.
Air filter
The Viessmann AirflowPLUS AH2A series of air handlers
are provided with a disposable filter media. This filter
should be inspected monthly and removed and replaced
as required.
Circulator
The circulator is water lubricated and should require no
regular maintenance. The system control has a pump
exercise function during prolonged periods of no heat
to avoid seizing from long idle periods.
5680 011 - 24
Coils
The heating coil should not require cleaning if the filter
maintenance schedule is adhered to. If a filter is damaged
or collapses from plugging, dust may foul the coils. If this
happens, remove the front covers, replace the filter and
carefully vacuum the bottom of the heating coil. During
this process, avoid dust from falling into the fan below.
49
Additional Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
System Layout 1
Refer to page 25 for the Viessmann AirflowPLUS
connection to external heat demand of the boiler.
50
IMPORTANT
Please note location of expansion tank.
Sizing of field-supplied pumps are critical for proper
boiler operation in this system layout. An undersized
pump may cause short-cycling and/or improper operation
of the boiler.
5680 011 - 24
Legend
A Vitocrossal 300 CU3A high mass boiler
B System fill with expansion tank
C Viessmann AirflowPLUS air handler
D Thermostat (field supplied)
E Indirect fired DHW storage tank
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Additional Information
System Layout 2
Legend
A Vitocrossal 300 CU3A high mass boiler
B System fill with expansion tank
C High temperature heating loop
D Viessmann AirflowPLUS air handler
E Thermostat (field supplied)
F Low temperature heating loop with mixing valve
G Indirect fired DHW storage tank
H Low loss header (or closely spaced tees)
5680 011 - 24
Refer to page 25 for the Viessmann AirflowPLUS
connection to external heat demand of the boiler.
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter) is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
System separation is required of underfloor heating
systems employing non-oxygen diffusion barrier tubing.
All components on the secondary side of the heat
exchanger must be made of corrosion-resistant materials.
The 3-way mixing valve, built-in to achieve the low
temperature level of the under floor heating circuit, is
controlled by an accessory kit for a heating circuit with
mixing valve.
51
Additional Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
System Layout 3
E Thermostat (field supplied)
F Low temperature heating loop with mixing valve
G Low loss header (or closely spaced tees)
Refer to page 25 for the Viessmann AirflowPLUS
connection to external heat demand of the boiler.
52
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter) is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler, or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
System separation is required of underfloor heating
systems employing non-oxygen diffusion barrier tubing.
All components on the secondary side of the heat
exchanger must be made of corrosion-resistant materials.
The 3-way mixing valve, built-in to achieve the low
temperature level of the under floor heating circuit, is
controlled by an accessory kit for a heating circuit with
mixing valve.
5680 011 - 24
Legend
A Vitodens 222-F B2TA/B boilers
B System fill with expansion tank
C High temperature heating loop
D Viessmann AirflowPLUS air handler
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Additional Information
System Layout 4
Legend
A Vitodens 200 B2HA/B boilers
B System fill with expansion tank
C High temperature heating loop
D Viessmann AirflowPLUS air handle
E Thermostat (field supplied)
F Low temperature heating loop with mixing valve
G Indirect fired DHW storage tank
H Low loss header (or closely spaced tees)
5680 011 - 24
Refer to page 25 for the Viessmann AirflowPLUS
connection to external heat demand of the boiler.
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter) is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler, or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
System separation is required of underfloor heating
systems employing non-oxygen diffusion barrier tubing.
All components on the secondary side of the heat
exchanger must be made of corrosion-resistant materials.
The 3-way mixing valve, built-in to achieve the low
temperature level of the under floor heating circuit, is
controlled by an accessory kit for a heating circuit with
mixing valve.
53
Additional Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
System Layout 5
Note: For installations with multiple air handler units,
the call for heat from each air handler must be
connected in parallel to the boiler demand.
Note: The low loss header is optional with the Vitocrossal
300 CU3A boiler.
54
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler, or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
System separation is required of underfloor heating
systems employing non-oxygen diffusion barrier tubing.
All components on the secondary side of the heat
exchanger must be made of corrosion-resistant materials.
The 3-way mixing valve, built-in to achieve the low
temperature level of the under floor heating circuit, is
controlled by an accessory kit for a heating circuit with
mixing valve.
5680 011 - 24
Legend
A Vitocrossal 300 CU3A high mass boiler / Vitodens
200 B2HA/B boilers (shown)
B System fill with expansion tank
C High temperature heating loop
D Viessmann AirflowPLUS air handler
E Thermostat (field supplied)
F Low temperature heating loop with mixing valve
G Indirect fired DHW storage tank
H Low loss header (or closely spaced tees)
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Additional Information
System Layout 6
Legend
A Vitodens 200 B2HA/B boilers
B System fill with expansion tank
C Thermostat (field supplied)
D Viessmann AirflowPLUS air handler
E Low loss header (or closely spaced tees)
5680 011 - 24
Refer to page 25 for the Viessmann AirflowPLUS
connection to external heat demand of the boiler.
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter) is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler, or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
Sizing of field-supplied pumps are critical for proper boiler
operation in this system layout. An undersized pump may
cause short-cycling and/or improper operation of the boiler.
55
Additional Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
System Layout 7
For Vitodens 100 B1HE refer to page 23 for the
Viessmann AirflowPLUS connection to OT of the boiler.
For Vitodens 100 B1HE refer to page 24.
56
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter) is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler, or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
If the heating system does not include a DHW storage
tank connected to the boiler the DHW demand contacts
of the boiler may be connected to the Viessmann
AirflowPLUS heat demand, use the DHW temperature
set point to set the desired supply temperature to the air
handler.
5680 011 - 24
Legend
A Vitodens 100 B1HA/B1HE boiler
B System fill with expansion tank
C Viessmann AirflowPLUS air handler
D Thermostat (field supplied)
F Indirect fired DHW storage tank
G Closely spaced tees (optional LLH accessory)
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Additional Information
System Layout 8
Legend
A Vitodens 100 B1KA/B1KE boiler
B System fill with expansion tank
C Viessmann AirflowPLUS air handler
D Thermostat (field supplied)
E Low loss header (or closely spaced tees)
5680 011 - 24
For Vitodens 100 B1HE refer to page 23 for the
Viessmann AirflowPLUS connection to OT of the boiler.
For Vitodens 100 B1HE refer to page 24.
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter) is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler, or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
57
Additional Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
System Layout 9
Legend
A Vitodens 200 B2HE series boiler
B System fill with expansion tank
C High temperature heating loop
D Viessmann AirflowPLUS air handler
E Thermostat (field supplied)
F Low temperature heating circuit with mixing valve
G Low loss header (or closely spaced tees)
H DHW tank
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter) is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler, or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
58
5680 011 - 24
Refer to page 26 for the Viessmann AirflowPLUS
connections.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Additional Information
System Layout 10
Legend
A Vitodens 200 B2HE series boiler
B System fill with expansion tank
C High temperature heating loop
D Viessmann AirflowPLUS air handler
E Thermostat (field supplied)
F Low temperature heating circuit with mixing valve
G Low loss header (or closely spaced tees)
H DHW tank
IMPORTANT
The use of a low-loss header (or closely spaced tees
with a maximum spacing of 4X pipe diameter) is strongly
recommended if the maximum water flow rate in the
application concerned exceeds the maximum or minimum
flow rates of the boiler, or if the system flow rates are
unknown.
The low-loss header is available as accessory part.
Please note location of expansion tank.
5680 011 - 24
Refer to page 26 for the Viessmann AirflowPLUS
connections
59
Additional Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Electrical Connections
Main power supply
120VAC, 1Ph, 60Hz, 12A
WARNING
Main
Disconnect
Switch
DISCONNECT POWER BEFORE
SERVICING BOILER.
External Connections
If any of the original wires as
supplied with the appliance must be
replaced, it must be replaced with
the exact equivalent.
Internal Connections
Power Connection
Terminal
CAUTION
>
Label all wires prior to disconnection
when servicing controls. Wiring errors
can cause improper and dangerous
operation. Verify proper operation
after servicing.
Door Safety
Switch
Viessmann AirflowPLUS
Connection Board
AC Line
PMP
XFO
XFI
ECM
Power
Thermostat - field supplied
(optional two stage
cooling shown)
60
Dry Contacts
A/C Relay
Heat
Fan
Alarm
5680 011 - 24
24VAC COM
24VAC
Fan Speed
Stage 2 Cool
Stage 1 Cool
Stage 1 Heat
ECM
Control
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Additional Information
Electrical Connections (continued)
Legend
1 Diagnostic LED
2 Ambient temperature sensor
3 Return air temperature sensor
4 Supply air temperature sensor
5 Freeze protection temperature sensor
7 Supply water temperature sensor
8 A/C power
9 Pump motor
10 24VAC transformer secondary
11 24VAC transformer primary
12 ECM power
13 ECM control
Legend
AC Line
1 115VAC line
2 115VAC neutral
Pump (PMP)
1 115VAC neutral
2 115VAC line
XFO
1 24VAC
2 N/C
3 24VAC-COM (GND)
XFI
1 115VAC line
2 115VAC neutral
ECM Power
1 N/C
2 N/C
3 N/C
ECM Control
1 Common C1
2 W/W1
3 Common C2
4 Delay tap select
5 Cool tap select
6 Y1
7 Adjust tap select
8 Output
9 Return valve (heat pump only)
qP Humidistat (BK)
qQ Heat tap select
qW 24VAC (R)
qE 2nd stage heat (EM/W2)
qR 2nd stage cool (Y/Y2)
qT Fan (G)
qZ Output +
5680 011 - 24
4 115VAC neutral
5 115VAC line
61
Additional Information
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Technical Data
Description
Motor (ECM)
Motor rated amps - loaded (1050 RPM)
- locked rotor
Electrical
Heating BTUH
(kW)
hp
AMPS
AMPS
VOLTS/PH/HZ
120°F (49°C)
140°F (60°C)
160°F (71°C)
180°F (82°C)
Flow
Nominal (CFM)
Cooling capacity
Cabinet
Supply air opening
Return air opening
Weight
Circulating pump *
Type
Volts
Motor horsepower
Capacitor
Motor rated amps - loaded
- locked rotor
Maximum working pressure
Min./max. fluid temperature
Hydronic heating coil
Construction
Rows...fins/in.
Total face area
Piping connections
Supply
Return
Pressure drop through the coil
USG/min
(L/H)
Heating .5” e.s.p.
Cooling .5” e.s.p.
Heating .2” e.s.p.
Cooling .2” e.s.p.
(tons)
D x W x H*
in.
(mm)
in.
(mm)
in.
(mm)
lb.
kg
AH2A-213
g
5.0
**
120/1/60
28,000
(8)
46,000
(13)
62,000
(18)
72,000
(21)
3
(681)
600
700
1,100
1,200
1.5 - 3.0
22c x 18 x 32b
(578 x 457 x 825)
16 x 20
(406 x 508)
14 x 18
(356 x 457)
85
(39)
AH2A-354
AH2A-385
b
c
7.7
9.6
**
**
120/1/60
120/1/60
44,000
51,000
(13)
(15)
61,000
74,000
(18)
(22)
83,000
90,000
(24)
(26)
98,000
115,000
(29)
(33)
5
5
(1135)
(1135)
1,200
1,600
1,400
1,800
1,900
1,300
2,100
1,600
2.50 - 4.0
3.5 - 5.0
23 x 22 x 34b
28 x 22 x 34b
(584 x 559 x 876) (711 x 559 x 876)
20 x 20
20 x 25
(508 x 508)
(508 x 635)
18 x 18
18 x 23
(457 x 457)
(457 x 584)
100
110
(45)
(50)
Grundfos 15/58RU
115
1/25
10/180
0.74
4.44
145
120/200
(49/93)
115
1/25
10/180
0.74
4.44
145
120/200
(49/93)
Copper tubing, aluminum fins, galvanized steel support frame
3...12
3...12
sq. ft. (m2)
1.3 (0.12)
2.8 (0.26)
3...12
2.8 (0.26)
AC
hp
MFD/VOLTS
AMPS
AMPS
PSI
ºF
(ºC)
in.
in.
feet of head
[@ 160°F (71°C)
supply water
temperature]
115
1/25
10/180
0.74
4.44
145
120/200
(49/93)
b FIP
b FIP
c FIP
c FIP
c FIP
c FIP
12
2
2
Permissible ambient temperature
Installation in living spaces or boiler rooms (standard
ambient conditions;
- During operation 32 to 104ºF (0 to +40ºC)
- During storage and transport -4 to 149ºF (-20 to +65ºC)
62
5680 011 - 24
* Using the adjustable levelling feet can add up to 1b in. (38 mm) to the height of the air handler.
** If motor speed decreases below the programmed stall speed, the motor will shut down and after a delay period,
the control will attempt to restart the motor. Starting current is limited to significantly less than full load current.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Additional Information
Parts List
Model No.
AH2A 213
AH2A 354
AH2A 385
Serial No.
7561230
7561231
7561232
Ordering Parts:
Please provide Model and Serial Number A when
ordering replacement parts. Order replacement
components from your Viessmann distributor.
Parts
0001
0002
0003
0004
0005
0006
0007
0008
0009
0010
0011
0012
0013
0014
0015
0016
0017
0018
0019
0020
0021
0023
0024
0025
0026
0027
0028
0029
0030
Side panel with return air opening
Side panel
Front panel, top
Front panel, bottom
Bracket for air filter
Panel, return air
Fan motor
Circuit board
Leveling feet (set of 4)
Bracket for fan motor
Blower housing
Blower wheel
Hot water coil
Circulation pump head, GF UPS15-58RU
Sensor for return air (T5)
Sensor for AC discharge air (T4) *1
Sensor for freeze protect (T3)
Sensor for supply water (T1)
Pump support block
Sensor, ambient (T6)
Diagnostic LED
Door safety switch
Terminal block (main power supply)
Transformer, 120VAC / 24VAC
Filter frame *2
Air filter *3
Power factor correction choke *4
Circuit board enclosure
Flow check valve
Other Parts (not illustrated)
0022 Sensor clamp
0050 Technical Data Manual
0051 Installation and Operating Instructions
0052 Parts List
*1
*2
*3
5680 011 - 24
*4
Sensor installed in downstream plenum.
For floor-standing installations only.
Please purchase quality replacement air
filters from a local hardware store:
AH2A 213 16 x 20 in.
AH2A 354 20 x 20 in.
AH2A 385 20 x 25 in.
Only for Model AH2A 385.
63
5680 011 - 24
Technical information subject to change without notice.
Printed on environmentally friendly
(recycled and recyclable) paper.
Viessmann AirflowPLUS AH2A Installation, Operating and Service
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