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Service Manual
PTAC PD Series (Electronic Controls)
Packaged Terminal Air Conditioners
Packaged Terminal Heat Pumps
• Standard Unit
• Seacoast Protected Unit
• Remote Thermostat Unit
P2KPD 1-05
TABLE OF CONTENTS
Introduction ............................................................................................................................................................ 3
Typical Unit Components ....................................................................................................................................... 3
Unit Identification ................................................................................................................................................... 4
Unit Specifications ................................................................................................................................................. 5
Sequence Of Operation ......................................................................................................................................... 6
Electrical Rating Tables ......................................................................................................................................... 7
Power Cord Information ......................................................................................................................................... 7
Digital Control Operation ....................................................................................................................................... 8
Digital Control Features .................................................................................................................................... 9-10
Remote Thermostat / Low Voltage Control Connections .....................................................................................11
Digital Control User Input Configuration .............................................................................................................. 12
Digital Control Diagnostics and Test Mode ......................................................................................................... 13
Calculating the Approximate CFM ....................................................................................................................... 14
Refrigerant Charging....................................................................................................................................... 14-16
Metering Device ................................................................................................................................................... 17
Reversing Valve Description/Operation .............................................................................................................. 17
Testing the Coil .................................................................................................................................................... 18
Compressor Checks ....................................................................................................................................... 19-21
Capacitors ............................................................................................................................................................ 21
Routine Maintenance ........................................................................................................................................... 22
Troubleshooting Charts...................................................................................................................................23-24
Wiring Diagram - Cooling Without Electric Heat ................................................................................................. 25
Wiring Diagram - Cooling With Electric Heat ...................................................................................................... 26
Wiring Diagram - Heat Pump With Electric Heat ................................................................................................ 27
2
INTRODUCTION
This service manual is designed to be used in conjunction with the installation manuals provided with each air
conditioning system component.
This service manual was written to assist the professional HVAC service technician to quickly and accurately
diagnose and repair any malfunctions of this product.
This manual, therefore, will deal with all subjects in a general nature. (i.e. All text will pertain to all models).
IMPORTANT: It will be necessary for you to accurately identify the unit you are
servicing, so you can be certain of a proper diagnosis and repair.
(See Unit Identification.)
Typical Unit Components
Discharge Air Grille
Blower Wheel
Indoor Blower Housing
Gasket
Control Door
Condenser Fan Blade
Outdoor Grille
Condenser
Shroud
Filters
Condenser
Coil
Return Air Grille
Evaporator Coil
Front Cover
Control Panel
Compressor
Wall Sleeve
Gasket Basepan
The information contained in this manual is intended for use by a qualified service technician who is
familiar with the safety procedures required in installation and repair, and who is equipped with the
proper tools and test instruments.
Installation or repairs made by unqualified persons can result in hazards subjecting the unqualified
person making such repairs to the risk of injury or electrical shock which can be serious or even fatal
not only to them, but also to persons being served by the equipment.
If you install or perform service on equipment, you must assume responsibility for any bodily injury
or property damage which may result to you or others. Friedrich Air Conditioning Company will not
be responsible for any injury or property damage arising from improper installation, service, and/or
service procedures.
3
UNIT IDENTIFICATION
Model Number Code
PD H 07 K 3 S B A
Series
PD = P Series Digital PTAC
Engineering Digit
Design Series
System
X = Accessory
E = Cooling with or
without electric heat
H = Heat Pump with
Auxiliary Heat
Options
S = Standard
R = Remote Thermostat
C = Seacoast Protection
X = Seacoast / Remote
Nominal Cooling Capacity
07 = 7000 BTUh
09 = 9000 BTUh
12 = 12000 BTUh
15 = 15000 BTUh
Nominal Heater Size
(@ 230V or 265V)
0 = No Heater
2 = 2.5KW
3 = 3.4KW
5 = 5.0KW
Voltage
K = 208/230V - 1Ph. - 60Hz.
R = 265V - 1Ph. - 60Hz.
PTAC Serial Number Identification Guide
Serial Number
Decade Manufactured
L=0
C=3
F=6
A=1
D=4
G=7
B=2
E=5
H=8
Year Manufactured
A=1
D=4
G=7
B=2
E=5
H=8
C=3
F=6
J=9
L
J=9
K=0
Month Manufactured
A=Jan D=Apr G=Jul K=Oct
B=Feb E=May H=Aug L=Nov
C=Mar F=Jun J=Sep M=Dec
4
E
A
P
00000
Production Run Number
PRODUCT LINE
R=RAC
P=PTAC
E=EAC
V=VPAK
H=Split
SPECIFICATIONS
GENERAL INFORMATION – PDE SERIES
Model
PDE07K
PDE07R
PDE09K
PDE09R
PDE12K
PDE12R
PDE15K
PDE15R
POWER
VOLTAGE (1 PHASE, 60 Hz)
230/208
265
230/208
265
230/208
265
230/208
265
VOLT RANGE
253-198
292-239
253-198
292-239
253-198
292-239
253-198
292-239
POWER (WATTS)
615/598
615
800/783
800
1091/1073
1091
1579/1578
1579
CURRENT (AMPS)
3
3
3.9
3.9
5.1
5.1
6.6
6.6
POWER FACTOR
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
AMPS L.R.
18
18
22.2
22.2
26.3
26.3
38
38
AMPS F.L.
3
3
3.9
3.9
5.1
5.1
6.8
6.8
1/15.
1/15.
1/12.
1/12.
1/10.
1/10.
1/10.
1/10.
27
27
30
30
28
28
28
28
7500/7300
7500
9200/9000
9200
12000/11800
12000
15000/14800
15000
INDOOR CFM
250
250
300
300
325
325
350
350
SENSIBLE HEAT RATIO
0.79
0.79
0.76
0.76
0.76
0.76
0.75
0.75
60
60
60
60
70
70
70
70
PDH07K
PDH07R
PDH09K
PDH09R
PDH12K
PDH12R
PDH15K
PDH15R
VOLTAGE (1 PHASE, 60 Hz)
230/208
265
230/208
265
230/208
265
230/208
265
VOLT RANGE
253-198
292-239
253-198
292-239
253-198
292-239
253-198
292-239
POWER (WATTS)
590/574
590
791/774
791
1121/1023
1121
1581/1559
1559
HORSEPOWER
R-22 CHARGE (OZ)
PERFORMANCE
COOLING BTUh
VENT CFM
GENERAL INFORMATION – PDH SERIES
Model
POWER
CURRENT (AMPS)
3
3
3.9
3.9
5.1
5.1
6.6
6.6
POWER FACTOR
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
AMPS L.R.
18
18
22.2
22.2
26.3
26.3
38
38
AMPS F.L.
3
3
3.9
3.9
5.1
5.1
6.8
6.8
1/15.
1/15.
1/12.
1/12.
1/10.
1/10.
1/10.
1/10.
27
27
32
32
34.5
34.5
33
33
COOLING BTUh
7200/7000
7000
9100/8900
9100
12000/11800
12000
14700/14500
14700
REVERSE HEATING BTUh
HORSEPOWER
R-22 CHARGE (OZ)
PERFORMANCE
6400/6200
6400
8100/7900
8100
10800/10600
10800
13500/13300
13500
INDOOR CFM
250
250
300
300
325
325
350
350
SENSIBLE HEAT RATIO
0.79
0.79
0.76
0.76
0.76
0.76
0.75
0.75
60
60
60
60
70
70
70
70
VENT CFM
5
SEQUENCE OF OPERATION
A good understanding of the basic operation of the refrigeration
system is essential for the service technician. Without this
understanding, accurate troubleshooting of refrigeration
system problems will be more difficult and time consuming,
if not (in some cases) entirely impossible. The refrigeration
system uses four basic principles (laws) in its operation they
are as follows:
1.
"Heat always flows from a warmer body to a cooler
body."
2. "Heat must be added to or removed from a substance
before a change in state can occur"
3.
"Flow is always from a higher pressure area to a lower
pressure area."
4.
"The temperature at which a liquid or gas changes state
is dependent upon the pressure."
The refrigeration cycle begins at the compressor. Starting
the compressor creates a low pressure in the suction line
which draws refrigerant gas (vapor) into the compressor. The
compressor then "compresses" this refrigerant, raising its
pressure and its (heat intensity) temperature.
The refrigerant leaves the compressor through the discharge
Line as a hot High pressure gas (vapor). The refrigerant enters
the condenser coil where it gives up some of its heat. The
condenser fan moving air across the coil's finned surface
facilitates the transfer of heat from the refrigerant to the
relatively cooler outdoor air.
When a sufficient quantity of heat has been removed from
the refrigerant gas (vapor), the refrigerant will "condense" (i.e.
change to a liquid). Once the refrigerant has been condensed
(changed) to a liquid it is cooled even further by the air that
continues to flow across the condenser coil.
The PTAC design determines at exactly what point (in the
condenser) the change of state (i.e. gas to a liquid) takes place.
In all cases, however, the refrigerant must be totally condensed
(changed) to a Liquid before leaving the condenser coil.
Suction
Line
Evaporator
Coil
The refrigerant leaves the condenser Coil through the liquid
line as a warm high pressure liquid. It next will pass through
the refrigerant drier (if so equipped). It is the function of the
drier to trap any moisture present in the system, contaminants,
and large particulate matter.
The liquid refrigerant next enters the metering device. The
metering device is a capillary tube. The purpose of the metering
device is to "meter" (i.e. control or measure) the quantity of
refrigerant entering the evaporator coil.
In the case of the capillary tube this is accomplished (by design)
through size (and length) of device, and the pressure difference
present across the device.
Since the evaporator coil is under a lower pressure (due to
the suction created by the compressor) than the liquid line,
the liquid refrigerant leaves the metering device entering the
evaporator coil. As it enters the evaporator coil, the larger area
and lower pressure allows the refrigerant to expand and lower
its temperature (heat intensity). This expansion is often referred
to as "boiling". Since the unit's blower is moving indoor air
across the finned surface of the evaporator coil, the expanding
refrigerant absorbs some of that heat. This results in a lowering
of the indoor air temperature, hence the "cooling" effect.
The expansion and absorbing of heat cause the liquid refrigerant
to evaporate (i.e. change to a gas). Once the refrigerant has
been evaporated (changed to a gas), it is heated even further
by the air that continues to flow across the evaporator coil.
The particular system design determines at exactly what
point (in the evaporator) the change of state (i.e. liquid to a
gas) takes place. In all cases, however, the refrigerant must
be totally evaporated (changed) to a gas before leaving the
evaporator coil.
The low pressure (suction) created by the compressor causes
the refrigerant to leave the evaporator through the suction line
as a cool low pressure vapor. The refrigerant then returns to
the compressor, where the cycle is repeated.
Discharge
Line
Condenser
Coil
Compressor
Metering
Device Refrigerant Drier
Liquid
Refrigerant
Line
Strainer
6
ELECTRICAL RATING TABLES
NOTE: Use Copper Conductors ONLY. Wire sizes are per NEC, check local codes for overseas applications.
Table 1
250 V Receptacles and Fuse Types
AMPS
15
20*
30
WIRE SIZE
Use ONLY wiring size recommended for
single outlet branch circuit.
FUSE/CIRCUIT
BREAKER
Use ONLY type and size fuse or HACR circuit breaker indicated on unit’s rating plate.
Proper current protection to the unit is the
responsibility of the owner. NOTE: A time
delay fuse is provided with 265V units.
GROUNDING
Unit MUST be grounded from branch circuit
through service cord to unit, or through separate ground wire provided on permanently
connected units. Be sure that branch circuit
or general purpose outlet is grounded. The
field supplied outlet must match plug on
service cord and be within reach of service
cord. Refer to Table 1 for proper receptacle
and fuse type. Do NOT alter the service cord
or plug. Do NOT use an extension cord.
RECEPTACLE
The field supplied outlet must match plug on
service cord and be within reach of service
cord. Refer to Table 1 for proper receptacle
and fuse type. Do NOT alter the service cord
or plug. Do NOT use an extension cord.
WIRE SIZING
Use recommended wire size given in Table
2 and install a single branch circuit. All wiring
must comply with local and national codes.
NOTE: Use copper conductors only.
RECEPTACLE
TIME-DELAY TYPE FUSE
(or HACR circuit breaker)
15
20
30
HACR – Heating, Air Conditioning, Refrigeration
* May be used for 15 Amp applications if fused for 15 Amp
NOTE: 265 volt units are hard wired.
Table 2
Recommended branch circuit wire sizes*
NAMEPLATE / MAXIMUM
CIRCUIT BREAKER SIZE
AWG WIRE SIZE**
15
20
30
14
12
10
AWG – American Wire Gauge
* Single circuit from main box
** Based on copper wire, single insulated conductor at 60°C
ELECTRIC SHOCK HAZARD! Turn off electric power before service or installation.
All electrical connections and wiring MUST be installed by a qualified electrician and
conform to the National Electrical Code and all local codes which have jurisdiction.
Failure to do so can result in property damage, personal injury and/or death.
POWER CORD INFORMATION (230/208V MODELS ONLY)
All Friedrich 230/208V PTAC units are shipped from the
factory with a Leakage Current Detection Interrupter (LCDI)
equipped power cord. The LCDI device meets the UL and
NEC requirements for cord connected air conditioners effective
August 2004.
To test your power supply cord:
1. Plug power supply cord into a grounded 3 prong outlet.
2. Press RESET.
NOTE: The LCDI device is not intended to be used as a
switch.
Once plugged in the unit will operate normally without the need
to reset the LCDI device. If the LCDI device trips and requires
resetting the cause of the trip should be identified prior to further
use of the PTAC.
If the device fails to trip when tested or if the power supply cord
is damaged it must be replaced with a new supply cord obtained
from the product manufacturer, and must not be repaired.
3. Press TEST (listen for click; Reset button trips and pops out).
4. Press and release RESET (listen for click; Reset button
latches and remains in). The power supply cord is ready for
operation.
30A LCDI Device
7"
4.1"
15/20A LCDI Device
TEST
2"
RESET
2"
Test Button
Reset Button
Test Button
Reset Button
7
DIGITAL CONTROL OPERATION
Temperature Display
The Friedrich digital PTAC is shipped from the factory to
display the desired room temperature on the LED readout.
Digital Control Panel
The unit can be configured to display the room temperature
by simultaneously pressing the ‘Cool’ and ‘High Fan’ buttons
for three seconds the display will show an ‘R’ for one seconds
to acknowledge the change. The unit will display the setpoint
or
buttons are pressed and then
whenever the ‘Temp’
switch back to room temperature.
To revert back to displaying the setpoint only press the ‘Cool’
and ‘Low Fan’ buttons for three seconds simultaneously, the
unit will display an ‘S’ for one seconds to acknowledge the
change.
ºF vs. ºC Display
The unit is factory configured to display all temperatures in
degrees Fahrenheit (º F). To switch to degrees Celsius press
the ‘Fan Only’ and ‘Low Fan’ buttons simultaneously for three
seconds. The display will show a ‘C’ as acknowledgement of
the change.
To revert back to º F press the ‘Fan Only’ and ‘Low Fan’
buttons simultaneously for three seconds. The display will
show an ‘F’ as acknowledgement of the change.
Cooling Mode
Pressing the ‘Cool’ button while the unit is in any mode,
including off, will put the unit into cooling mode. Adjust the
temperature readout to the desired room temperature and
the unit will cycle the compressor on and off to maintain a
comfortable room. The compressor will come on anytime that
the room temperature is 1.8°F above the desired temperature.
The fan operation is dependent on the fan mode selected,
either continuous or cycling. See page 16 for fan cycle
control.
Heating Mode
Pressing the ‘Heat’ button while the unit is in any mode,
including off, will put the unit into heating mode.
Heat Pump Models (PDH)
When the ‘Heat’ button is pressed initially the unit will energize
the electric resistance heat to quickly bring the room to the
set temperature. When the desired room temperature falls
1.8°F below the desired set temperature the unit will cycle
the compressor on and operate as a heat pump to maintain
the room temperature while running more efficiently than
resistance heat only models. If the room temperature should
fall more than 5°F from the set temperature the unit will run
the resistance heater. The fan operation is dependent on the
fan mode selected, either continuous or cycling. Dip switch 5
controls the fan mode, see page 16 for setting.
When the outdoor coil temperature falls below 30°F for more
than 2 minutes the unit will operate the resistance heaters
8
and not the compressor. When the outdoor coil temperature
reaches 45°F the compressor will be allowed to operate
again.
Heat/Cool Models (PDE)
After pressing the ‘Heat’ button, adjust the temperature
readout to the desired room temperature and the unit will cycle
the resistance heat on and off to maintain a comfortable room.
The heater will come on anytime that the room temperature
is 1.8°F below the desired temperature. The fan operation is
dependent on the fan mode selected, either continuous or
cycling. Dip switch 5 controls the fan mode, see page 16 for
setting.
Emergency Heat Operation
In the event of a compressor failure in heat pump mode the
compressor may be locked out to provide heat through the
resistance heater. This feature ensures that even in the unlikely
event of a compressor failure the room temperature can be
maintained until the compressor can be serviced. Dip switch
7 controls the emergency heat setting, see page 16.
Fan Mode
Fan Only
Pressing the ‘Fan Only’ button will run the fan to allow for
air circulation in the room without operating the compressor
or heater regardless of the room or set temperature. The fan
speed selection is made by pressing either the ‘High Fan’ or
‘Low Fan’ button.
Cycle/Continuous
The owner may choose between fan cycling or fan
continuous mode based on property preference. (Note:
Even heat monitoring and quiet start/stop fan delay only
operate in fan cycle mode) Fan continuous mode is used
to keep constant airflow circulation in the room during all
times the unit is ‘ON’. Fan cycle will conserve energy by
only operating the fan while the compressor or electric
heater is operating. Dip switch 5 controls the fan mode,
see page 16 for setting.
FRIEDRICH DIGITAL CONTROL FEATURES
The new Friedrich digital PTAC has state of the art features to improve guest comfort, indoor air quality and conserve
energy. Through the use of specifically designed control software for the PTAC industry Friedrich has accomplished what
other Manufacturer’s have only attempted – a quiet, dependable, affordable and easy to use PTAC.
Below is a list of standard features on every Friedrich PTAC and their benefit to the owner.
Digital Temperature
Readout
By digitally monitoring desired room temperature the room is controlled more precisely than conventional systems. The large, easy to read LED display can show either set-point or actual room temperature as selected
by owner.
One-Touch
Operation
When the unit is powered off the unit can be returned directly to heating or cooling mode by pressing the ‘Heat’
or ‘Cool’ buttons without the confusing power up sequence of some controls. One-touch control takes guesswork out of unit control delivering a more enjoyable experience and eliminating front-desk calls.
Individual Mode and
Fan Control Buttons
By having separate control buttons and indicators for both fan and mode settings the Friedrich digital control
eliminates the confusion of previous digital PTACs. The accurate temperature setting provides greater guest
comfort than other systems.
Quiet Start/Stop
Fan Delay
The fan start and stop delays prevent abrupt changes in room acoustics due to the compressor energizing or
stopping immediately. Upon call for cooling or heating the unit fan will run for five seconds prior to energizing
the compressor. Also, the fan off delay allows for “free cooling” by utilizing the already cool indoor coil to its
maximum capacity by running for 30 seconds after the compressor.
Remote Thermostat
Operation
Some applications require the use of a wall mounted thermostat. All new Friedrich PTACs may be switched from
unit control to remote thermostat control easily without the need to order a special model or accessory kit.
Wireless Remote
Control Ready
Guests can adjust the temperature and mode of the unit through the use of an optional hand held wireless
remote, improving guest comfort and relaxation.
Internal Diagnostic
Program
The new Friedrich digital PTAC features a self diagnostic program that can alert maintenance to component
failures or operating problems. The internal diagnostic program saves properties valuable time when diagnosing running problems.
Service Error Code
Storage
The self diagnosis program will also store error codes in memory if certain conditions occur and correct themselves such as extreme high or low operating conditions or activation of the room freeze protection feature.
Storing error codes can help properties determine if the unit faced obscure conditions or if an error occurred
and corrected itself.
Constant Comfort
Room Monitoring
The on-board processor monitors time between demand cycles (heat or cool) and will cycle the fan every 9
minutes to sample the room condition and determine if the desired conditions are met. This allows the room to
have similar benefits to a remote mounted stat without the complication or cost of a wall mounted thermostat.
Electronic
Temperature
Limiting
By limiting the operating range the property can save energy by eliminating “max cool” or “max heat” situations
common with older uncontrolled systems. The new electronic control allows owners to set operating ranges
for both heating and cooling independently of one another.
Room Freeze
Protection
When the PTAC senses that the indoor room temperature has fallen to 40°F the unit will cycle on high fan and
the electric strip heat to raise the room temperature to 46°F then cycle off again. This feature works regardless
of the mode selected and can be turned off. The control will also store the Room Freeze cycle in the service
code memory for retrieval at a later date. This feature ensures that unoccupied rooms do not reach freezing
levels where damage can occur to plumbing and fixtures.
Random
Compressor Restart
Multiple compressors starting at once can often cause electrical overloads and premature unit failure. The
random restart delay eliminates multiple units from starting at once following a power outage or initial power
up. The compressor delay will range from 180 to 240 seconds.
Digital Defrost
Thermostat
The new Friedrich PTAC uses a digital thermostat to accurately monitor the outdoor coil conditions to allow the
heat pump to run whenever conditions are correct. Running the PTAC in heat pump mode save energy and
reduces operating costs. The digital thermostat allows maximization of heat pump run time.
9
FRIEDRICH DIGITAL CONTROL FEATURES CONTINUED
10
Instant Heat
Heat Pump Mode
Heat pump models will automatically run the electric heater to quickly bring the room up to temperature when
initially energized, then return to heat pump mode. This ensures that the room is brought up to temperature
quickly without the usual delay associated with heat pump units.
Even Heat Monitoring
The digital control monitors indoor conditions to ensure that the room temperature is within five degrees of
the setpoint. If necessary the unit will cycle the electric heat to maintain the temperature. This feature ensures guest comfort by delivering the heating benefits of an electric heater while maintaining the efficiency
benefits of a heat pump.
Fan Cycle Control
The owner may choose between fan cycling or fan continuous mode based on property preference. (Note:
Even heat monitoring and quiet start/stop fan delay only operate in fan cycle mode) Fan continuous mode is
used to keep constant airflow circulation in the room during all times the unit is ‘ON’. Fan cycle will conserve
energy by only operating the fan while the compressor or electric heater is operating.
Emergency Heat
Override
In the event of a compressor failure in heat pump mode the compressor may be locked out to provide heat
through the resistance heater. This feature ensures that even in the unlikely event of a compressor failure the
room temperature can be maintained until the compressor can be serviced.
Desk Control Ready
All Friedrich digital PTACs have low voltage terminals ready to connect a desk control energy management
system. Controlling the unit from a remote location like the front desk can reduce energy usage and requires
no additional accessories at the PTAC.
Indoor Coil Frost
Sensor
The frost sensor protects the compressor from damage in the event that airflow is reduced or low outdoor
temperatures cause the indoor coil to freeze. When the indoor coil reaches 30°F the compressor is diabled
and the fan continues to operate based on demand. Once the coil temperature returns to 45°F the compressor returns to operation.
Ultra-Quiet Air System
The new Friedrich PD series units feature a indoor fan system design that reduces sound levels without
lowering airflow and preventing proper air circulation.
High Efficiency
The Friedrich PTAC benefits quality components and extensive development to ensure a quiet, efficient and
dependable unit.
Single Motor
Friedrich’s single-motor design allows for enhanced outdoor airflow and simplifies the unit design without the
need for redundant components.
Rotary Compressor
High efficiency rotary compressors are used on all Friedrich PTACs to maximize durability and efficiency.
Auxiliary Fan Ready
The Friedrich PTAC features a 24V AC terminal for connection to an auxiliary fan that may be used to transfer
air to adjoining rooms. Auxiliary fans can provide conditioning to multiple rooms without the requirement of
multiple PTAC units.
Aluminum Endplates
All Friedrich PTACs are built with .04" endplates made from aluminum as opposed to steel. The endplates
are typically the most susceptible area for corrosion and aluminum is far more resistant to corrosion than
even coated steel.
Seacoast Protection
Optional Seacoast protection is available to protect the outdoor coil from harsh environments. The Friedrich
Seacoast process includes dipping the entire outdoor coil in a 7-step coating process that provides superior
protection to only coating the fins of the coil.
Top Mounted Antimicrobial Air Filters
All Friedrich PTAC return air filters feature an anti-microbial element that has proven to prevent mold and
bacterial growth in laboratory testing. PDXFT replacement filter kits feature the same anti-microbial agent.
All filters are washable and reusable and are easily accessed from the top of the unit without the removal of
the front cover.
Filtered Fresh Air
Intake
Friedrich PTAC units are capable of introducing up to 70 CFM of outside air into the conditioned space. The
outdoor air passes through a washable mesh filter to prevent debris from entering the airstream.
REMOTE THERMOSTAT AND LOW VOLTAGE
CONTROL CONNECTIONS
Room Thermostats
Location
Room thermostats are available from several different
manufacturers in a wide variety of styles. They range from
the very simple Bimetallic type to the complex electronic setback type. In all cases, no matter how simple or complex,
they are simply a switch (or series of switches) designed to
turn equipment (or components) "ON" or "OFF" at the desired
conditions.
The thermostat should not be mounted where it may be
affected by drafts, discharge air from registers (hot or cold),
or heat radiated from the sun or appliances.
An improperly operating, or poorly located room thermostat
can be the source of perceived equipment problems. A careful
check of the thermostat and wiring must be made then to
insure that it is not the source of problems.
Mercury bulb type thermostats MUST be level to control
temperature accurately to the desired set-point. Electronic
digital type thermostats SHOULD be level for aesthetics.
Remote Thermostat
All Friedrich PD model PTAC units are factory configured to
be controlled by either the chassis mounted Smart Center
or a 24V single stage remote wall mounted thermostat. The
thermostat may be auto or manual changeover as long as the
control configuration matches that of the PTAC unit.
The thermostat should be located about 5 Ft. above the floor
in an area of average temperature, with good air circulation.
Close proximity to the return air grille is the best choice.
Thermostat Location
To control the unit with a wall mounted thermostat follow
the steps below:
1) With the front cover removed locate the low voltage
terminal strip at the lower portion of the Smart Center.
2) Remove the jumper between the ‘GL’ and GH’
terminals.
3) The control is now configured for control by a wall
thermostat. The Smart Center will no longer control the
unit.
4) If desired the accessory escutcheon kit (PDXRT) is to
be used, install it over the existing control panel.
Note: To revert back to the Smart Center control of the unit
replace the jumper wire between the ‘GL’ and ‘GH’ terminals
that was removed in step 1.
Thermostat Connections
C
W
Y
R
GL
GH
B
=
=
=
=
=
=
=
Common Ground
Call for Heating
Call for Cooling
24V Power from Unit
Call for Low Fan
Call for High Fan
Reversing Valve Energized in heating mode
(PDH Models Only)
*If only one G terminal is present on thermostat connect to
GL for low fan or to GH for high fan operation.
11
DIGITAL CONTROL USER INPUT CONFIGURATION
The adjustable control dip switches are located at the lower left hand portion of the digital Smart Center. The inputs are only
visible and accessible with the front cover removed from the PTAC.
Dip Switch Setting
1) Electronic Temperature Limiting – Switches 1-4
The digital control is set from the factory to allow a temperature range between 60°F and 90°F in both heating and cooling mode. Dip Switches 1-4 can be used to set high and low
limits for either heating or cooling or both.
From the factory all four switches are in the up ‘ON’ position.
The charts to the right show the available electronic limiting
ranges.
2) Fan Cycle Control – Switch 5
All PTACs are shipped from the factory with Dip Switch 5 in the
‘OFF’ position to cycle the fan only when there is a demand for
the compressor or heater. As an option the fan may be set to
‘continuous’ mode by switching Dip Switch 5 to ‘ON’ position
to run the fan continuously while the unit is powered on.
To ensure that the room temperature is maintained evenly while
in fan cycle mode the Even Temp Load Anticipation feature
is enabled. Quiet Fan Delay is also enabled in fan cycle mode
to lessen the acoustical change between compressor start
up and shut off by running the fan for 5 seconds before each
demand cycle, and 30 seconds after cooling or 15 seconds
after heating cycles.
Heating Range Switches 1 & 2
Temperature
Range
Low
60
60
60
60
High
90
87
84
81
Dip
Switch
1
On
Off
Off
On
2
On
On
Off
Off
Cooling Range Switches 3 & 4
Temperature
Range
Low
60
63
66
69
High
90
90
90
90
Dip
Switch
3
On
On
Off
Off
4
On
Off
Off
On
Factory Dip Switch Configuration
3) Room Freeze Protection – Switch 6
Units are shipped from the factory with the room freeze
protection disabled. Room Freeze Protection can be switched
on at the owner’s preference by moving Dip Switch 6 to ‘ON’.
This feature will monitor the indoor room conditions and in the
event that the room falls below 40°F the unit will cycle on high
fan with the electric heater. This occurs regardless of mode.
4) Emergency Heat Override – Switch 7
In the unlikely event of a compressor failure a heat pump unit
may be switched to operate in only the electric heat mode until
repairs can be made. Moving Dip Switch 7 to ‘ON’.
Note: PTAC must be disconnected from power supply
when making any configuration changes.
12
O 1 2 3 4 5 6 7 8
N
DIGITAL CONTROL DIAGNOSTICS AND TEST MODE
Diagnostics
Test Mode
The Friedrich Smart Center continuously monitors the PTAC
unit operation and will store service codes if certain conditions
are witnessed. In some cases the unit may take action and
shut the unit off until conditions are corrected.
For service and diagnostic use only, the built-in timers and
delays on the PTAC may be bypassed by pressing the ‘Cool’
and ‘Low Fan’ buttons simultaneously for three seconds while
in any mode to enter the test mode. TE will be displayed when
entering test mode, and DE will be displayed when exiting.
The test mode will automatically be exited 30 minutes after
entering it or by pressing the ‘Cool’ and ‘Low Fan’ buttons
simultaneously for three seconds.
To access the error code menu press the ‘Heat’ and ‘High
Fan’ buttons simultaneously for three seconds. If error codes
are present they will be displayed. If multiple codes exist you
can toggle between messages using the temp button. To
clear all codes press the temp
button for three seconds
while in the error code mode. To exit without changing codes
press the ‘Low Fan’ button.
The chart below lists the possible error codes and their description:
ERROR
CODE
CODE TRANSLATION
ACTION TAKEN BY UNIT
POSSIBLE CAUSE
01
NOT USED
02
An extreme low voltage condition
exists <198V for 230V units and
<239V for 265V units.
Shut down unit. Display Error code and flash.
Once voltage rises to normal level system
power is restored.
• Inadequate power supply
• Defective breaker
• Blown fuse
03
Return air thermistor sensor open
or short circuit
Set return air sensor = 75°F. Alternate flash set
point and error code. Leave unit running.
• Defective sensor
04
Indoor coil thermistor sensor open
Or short circuit
Set ID coil temp = 40°F. Alternate flash set
point and error code. Leave unit running.
• Defective sensor
05
Outdoor coil thermistor sensor
open Or short circuit
Set OD coil temp = 20°F. Alternate flash set
point and error code. Automatically change
over to Electric heat Mode only. Leave unit
running.
• Defective sensor
06
If O.D. coil Temperature > 175 Deg
F for 2 consecutive minutes. (Heat
Pump models only)
Alternate flash set point and error code. Shut
unit down for 5 minutes, then try again 2 times,
if fails the 3rd time, then shut down unit.
07
NONE
•
•
•
•
Dirty coil
Fan motor failure
Restricted air flow
Non-condensables in
refrigeration system
I.D coil temperature <30 Deg F for
2 consecutive minutes.
Alternate flash set point and error code. Continue fan operation while the compressor
is locked out until the indoor coil thermistor
reaches 45° F, and then energize the compressor. However, compressor must still wait
a lockout time of 180 to 240 seconds.
•
•
•
•
•
•
Dirty filters
Dirty coil
Fan motor failure
Restricted airflow
Improper refrigerant charge
Restriction in refrigerant circuit
08
If unit cycles (Heat or Cool
demand)> 9 times per hour
Alternate flash set point and error code. Keep
unit running.
• Unit oversized
• Low load conditions
09
If unit cycles (Heat or Cool
demand)< 3 times per hour
Alternate flash set point and error code. Keep
unit running.
• Unit undersized
• High load conditions
10
Room Freeze Protection triggered
Alternate flash set point and error code. Keep
unit running.
• Room temperature fell below
40°F
13
CALCULATING THE APPROXIMATE CFM
The approximate CFM actually being delivered can be
calculated by using the following formula:
EXAMPLE: Measured voltage to unit (heaters) is 230 volts.
Measured Current Draw of strip heaters is 11.0 amps.
230 x 11.0 = 2530
2530/1000 = 2.53 Kilowatts
2.53 x 3413 = 8635
KILOWATTS x 3413
Temp. Rise x 1.08
DO NOT simply use the Kilowatt Rating of the heater (i.e.
2.5, 3.4, 5.0) as this will result in a less-than-correct airflow
calculation. Kilowatts may be calculated by multiplying the
measured voltage to the unit (heater) times the measured
current draw of all heaters (ONLY) in operation to obtain watts.
Kilowatts are then obtained by dividing by 1000.
Supply Air
Return Air
Temperature Rise
95°F
75°F
20°
20 x 1.08 = 21.6
= CFM
8635 = 400 CFM
21.6
REFRIGERANT CHARGING
NOTE: Because The Ptac System Is A Sealed System,
Service Process Tubes Will Have To Be Installed. First
Install A Line Tap And Remove Refrigerant From System.
Make Necessary Sealed System Repairs And Vacuum
System. Crimp Process Tube Line And Solder End Shut.
Do Not Leave A Service Valve In The Sealed System.
Proper refrigerant charge is essential to proper unit operation.
Operating a unit with an improper refrigerant charge will
result in reduced performance (capacity) and/or efficiency.
Accordingly, the use of proper charging methods during
servicing will insure that the unit is functioning as designed
and that its compressor will not be damaged.
Too much refrigerant (overcharge) in the system is just as bad
(if not worse) than not enough refrigerant (undercharge). They
both can be the source of certain compressor failures if they
remain uncorrected for any period of time. Quite often, other
problems (such as low air flow across evaporator, etc.) are
misdiagnosed as refrigerant charge problems. The refrigerant
circuit diagnosis chart will assist you in properly diagnosing
these systems.
An overcharged unit will at times return liquid refrigerant
(slugging) back to the suction side of the compressor
eventually causing a mechanical failure within the compressor.
This mechanical failure can manifest itself as valve failure,
bearing failure, and/or other mechanical failure. The specific
type of failure will be influenced by the amount of liquid being
returned, and the length of time the slugging continues.
Not enough refrigerant (undercharge) on the other hand,
will cause the temperature of the suction gas to increase
to the point where it does not provide sufficient cooling for
the compressor motor. When this occurs, the motor winding
14
temperature will increase causing the motor to overheat
and possibly cycle open the compressor overload protector.
Continued overheating of the motor windings and/or cycling
of the overload will eventually lead to compressor motor or
overload failure.
Method Of Charging
The acceptable method for charging the PTAC system is the
Weighed in Charge Method. The weighed in charge method
is applicable to all units. It is the preferred method to use, as
it is the most accurate.
The weighed in method should always be used whenever
a charge is removed from a unit such as for a leak repair,
compressor replacement, or when there is no refrigerant
charge left in the unit. To charge by this method, requires the
following steps:
1.
Install a piercing valve to remove refrigerant from the
sealed system. (Piercing valve must be removed from
the system before recharging.)
2. Recover Refrigerant in accordance with EPA regulations.
3. Install a process tube to sealed system.
4.
Make necessary repairs to system.
5. Evacuate system to 300 microns or less.
6. Weigh in refrigerant with the property quantity of R-22
refrigerant.
7.
Start unit, and verify performance.
8. Crimp the process tube and solder the end shut.
NOTE: In order to access the sealed system it will be necessary to install Schrader type fittings to the process tubes on
the discharge and suction of the compressor. Proper recovery refrigerant procedures need to be adhered to as outlined in
EPA Regulations. THIS SHOULD ONLY BE ATTEMPTED BY QUALIFIED SERVICE PERSONNEL.
Undercharged Refrigerant Systems
An undercharged system will result in poor performance (low
pressures, etc.) in both the heating and cooling cycle.
Whenever you service a unit with an undercharge of
refrigerant, always suspect a leak. The leak must be repaired
before charging the unit.
To check for an undercharged system, turn the unit on, allow
the compressor to run long enough to establish working
pressures in the system (15 to 20 minutes).
During the cooling cycle you can listen carefully at the exit
of the metering device into the evaporator; an intermittent
hissing and gurgling sound indicates a low refrigerant charge.
Intermittent frosting and thawing of the evaporator is another
indication of a low charge, however, frosting and thawing can
also be caused by insufficient air over the evaporator.
Checks for an undercharged system can be made at the
compressor . If the compressor seems quieter than normal,
it is an indication of a low refrigerant charge. A check of the
amperage drawn by the compressor motor should show a
lower reading. (Check the Unit Specification.) After the unit
has run 10 to 15 minutes, check the gauge pressures.
Gauges connected to system with an undercharge will
have low head pressures and substantially low suction
pressures.
Overcharged Refrigerant Systems
Compressor amps will be near normal or higher. Noncondensables can also cause these symptoms. To confirm, remove
some of the charge, if conditions improve, system may be
overcharged. If conditions don’t improve, Noncondensables
are indicated.
Whenever an overcharged system is indicated, always make
sure that the problem is not caused by air flow problems.
Improper air flow over the evaporator coil may indicate some
of the same symptoms as an overcharged system.
An over charge can cause the compressor to fail, since it
would be "slugged" with liquid refrigerant.
The charge for any system is critical. When the compressor
is noisy, suspect an overcharge, when you are sure that the
air quantity over the evaporator coil is correct. Icing of the
evaporator will not be encountered because the refrigerant
will boil later if at all. Gauges connected to system will usually have higher head pressure (depending upon amount of
overcharge). Suction pressure should be slightly higher.
15
Restricted Refrigerant System
Troubleshooting a restricted refrigerant system can be difficult.
The following procedures are the more common problems and
solutions to these problems. There are two types of refrigerant
restrictions: Partial restrictions and complete restrictions.
A partial restriction allows some of the refrigerant to circulate
through the system.
With a complete restriction there is no circulation of refrigerant
in the system.
Restricted refrigerant systems display the same symptoms as
a "low-charge condition."
When the unit is shut off, the gauges may equalize very
slowly.
Gauges connected to a completely restricted system will run
in a deep vacuum. When the unit is shut off, the gauges will
not equalize at all.
A quick check for either condition begins at the evaporator.
With a partial restriction, there may be gurgling sounds at the
metering device entrance to the evaporator. The evaporator
in a partial restriction could be partially frosted or have an ice
ball close to the entrance of the metering device. Frost may
continue on the suction line back to the compressor.
Often a partial restriction of any type can be found by feel,
as there is a temperature difference from one side of the
restriction to the other.
With a complete restriction, there will be no sound at the
metering device entrance. An amperage check of the
compressor with a partial restriction may show normal current
when compared to the unit specification. With a complete
restriction the current drawn may be considerably less than
normal, as the compressor is running in a deep vacuum (no
load.) Much of the area of the condenser will be relatively cool
since most or all of the liquid refrigerant will be stored there.
The following conditions are based primarily on a system in
the cooling mode.
16
METERING DEVICE
Capillary Tube Systems
All units are equipped with capillary tube metering devices.
3.
Switch the unit to the heating mode and observe the
gauge readings after a few minutes running time. If
the system pressure is lower than normal, the heating
capillary is restricted.
4.
If the operating pressures are lower than normal in both
the heating and cooling mode, the cooling capillary is
restricted.
Checking for restricted capillary tubes.
1.
Connect pressure gauges to unit.
2.
Start the unit in the cooling mode. If after a few minutes
of operation the pressures are normal, the check valve
and the cooling capillary are not restricted.
REVERSING VALVE DESCRIPTION/OPERATION
The Reversing Valve controls the direction of refrigerant
flow to the indoor and outdoor coils. It consists of a
pressure-operated, main valve and a pilot valve actuated
by a solenoid plunger. The solenoid is energized during the
heating cycle only. The reversing valves used in the PTAC
system is a 2-position, 4-way valve
The single tube on one side of the main valve body is the
high-pressure inlet to the valve from the compressor. The
center tube on the opposite side is connected to the low
pressure (suction) side of the system. The other two are
connected to the indoor and outdoor coils. Small capillary
tubes connect each end of the main valve cylinder to the
"A" and "B" ports of the pilot valve. A third capillary is a
common return line from these ports to the suction tube
on the main valve body. Four-way reversing valves also
have a capillary tube from the compressor discharge tube
to the pilot valve.
The piston assembly in the main valve can only be shifted
by the pressure differential between the high and low sides
of the system. The pilot section of the valve opens and
closes ports for the small capillary tubes to the main valve
to cause it to shift.
NOTE: System operating pressures must be near
normal before valve can shift.
DANGER OF BODILY INJURY OR DEATH
FROM ELECTRICAL SHOCK
The reversing valve solenoid is connected to
high voltage. Turn off electrical power before
disconnecting or connecting high voltage wiring or
servicing valve.
17
TESTING THE COIL
1. Turn off high voltage electrical power to unit.
2. Unplug line voltage lead from reversing valve coil.
3. Check for electrical continuity through the coil. If you
do not have continuity replace the coil.
4. Check from each lead of coil to the copper liquid line as
it leaves the unit or the ground lug. There should be no
continuity between either of the coil leads and ground;
if there is, coil is grounded and must be replaced.
5. If coil tests okay, reconnect the electrical leads .
6. Make sure coil has been assembled correctly.
Checking the Reversing Valve
NOTE: You must have normal operating pressures before
the reversing valve can shift.
Check for proper refrigerant charge. Sluggish or sticky
reversing valves can sometimes be remedied by reversing
the valve several time with the airflow restricted to increase
system pressure.
To raise head pressure during the cooling season the
airflow through the outdoor coil can be restricted . During
heating the indoor air can be restricted by blocking the
return air.
Dented or damaged valve body or capillary tubes can
prevent the main slide in the valve body from shifting.
If you determine this is the problem, replace the reversing
valve.
After all of the previous inspections and checks have been
made and determined correct, then perform the "Touch
Test" on the reversing valve.
Reversing Valve in Heating Mode
Touch Test in Heating/Cooling Cycle
The only definite indications that the slide is in the
mid-position is if all three tubes on the suction side of the
valve are hot after a few minutes of running time.
NOTE: A condition other than those illustrated above, and
on Page 28, indicate that the reversing valve is not shifting
properly. Both tubes shown as hot or cool must be the same
corresponding temperature.
Procedure For Changing Reversing Valve
1.
Install Process Tubes. Recover refrigerant from sealed
system. PROPER HANDLING OF RECOVERED REFRIGERANT ACCORDING TO EPA REGULATIONS
IS REQUIRED.
2. Remove solenoid coil from reversing valve. If coil is to be
reused, protect from heat while changing valve.
Never energize the coil when it is removed
from the valve as a coil burnout will result.
3. Unbraze all lines from reversing valve.
4. Clean all excess braze from all tubing so that they will
slip into fittings on new valve.
5. Remove solenoid coil from new valve.
6. Protect new valve body from heat while brazing with
plastic heat sink (ThermoTrap) or wrap valve body with
wet rag.
7.
18
Fit all lines into new valve and braze lines into new
valve.
Make sure that the ends of the lead do not touch
the compressor shell since this will cause a short
circuit.
Determine L.R.V.
Start the compressor with the voltmeter attached; then
stop the unit. Attempt to restart the compressor within a
couple of seconds and immediately read the voltage on the
meter. The compressor under these conditions will not start
and will usually kick out on overload within a few seconds
since the pressures in the system will not have had time to
equalize. Voltage should be at or above minimum voltage
of 197 VAC, as specified on the rating plate. If less than
minimum, check for cause of inadequate power supply; i.e.,
incorrect wire size, loose electrical connections, etc.
Reversing Valve in Cooling Mode
8. Pressurize sealed system with a combination of R-22
and nitrogen and check for leaks, using a suitable leak
detector. Recover refrigerant per EPA guidelines.
9. Once the sealed system is leak free, install solenoid coil
on new valve and charge the sealed system by weighing
in the proper amount and type of refrigerant as shown
on rating plate. Crimp the process tubes and solder the
ends shut. Do not leave Schrader or piercing valves in
the sealed system.
DANGER OF BODILY INJURY OR DEATH
FROM ELECTRICAL SHOCK
When working on high voltage equipment - turn the
electrical power off before attaching test leads.
Use test leads with alligator type clips - clip to
terminals, turn power on, take reading - turn power
off before removing leads.
Amperage (L.R.A.) Test
The running amperage of the compressor is the most
important of these readings. A running amperage higher
than that indicated in the performance data indicates that
a problem exists mechanically or electrically.
Single Phase Running and L.R.A. Test
NOTE: Consult the specification and performance section
for running amperage. The L.R.A. can also be found on
the rating plate.
Select the proper amperage scale and clamp the
meter probe around the wire to the "C" terminal of the
compressor.
Turn on the unit and read the running amperage on the
meter. If the compressor does not start, the reading will
indicate the locked rotor amperage (L.R.A.).
External Overload
The compressor is equipped with an external overload
which senses both motor am per age and winding
temperature. High motor temperature or amperage heats
the overload causing it to open, breaking the common
circuit within the compressor.
Locked Rotor Voltage (L.R.V.) Test
Heat generated within the compressor shell, usually due
to recycling of the motor, is slow to dissipate. It may take
anywhere from a few minutes to several hours for the
overload to reset.
Locked rotor voltage (L.R.V.) is the actual voltage available
at the compressor under a stalled condition.
Checking the External Overload
COMPRESSOR CHECKS
Single Phase Connections
Disconnect power from unit. Using a voltmeter, attach one
lead of the meter to the run "R" terminal on the compressor
and the other lead to the common "C" terminal of the compressor. Restore power to unit.
With power off, remove the leads from com pressor
terminals. If the compressor is hot, allow the overload
to cool before starting check. Using an ohmmeter, test
continuity across the terminals of the external overload. If
you do not have continuity; this indicates that the overload
is open and must be replaced.
19
Single Phase Resistance Test
Remove the leads from the compressor terminals and set
the ohmmeter on the lowest scale (R x 1).
Touch the leads of the ohmmeter from terminals common
to start ("C" to "S"). Next, touch the leads of the ohmmeter
from terminals common to run ("C" to "R").
Add values "C" to "S" and "C" to "R" to geth er and
check resistance from start to run terminals ("S" to "R").
Resistance "S" to "R" should equal the total of "C" to "S"
and "C" to "R."
In a single phase PSC compressor motor, the highest
value will be from the start to the run connections (“S” to
"R"). The next highest resistance is from the start to the
common connections ("S" to "C"). The lowest resistance
is from the run to common. ("C" to "R") Before replacing a
compressor, check to be sure it is defective.
Check the complete electrical system to the compressor
and compressor internal electrical system, check to be
certain that compressor is not out on internal overload.
Complete evaluation of the system must be made whenever
you suspect the compressor is defective. If the compressor
has been operating for some time, a careful examination
must be made to determine why the compressor failed.
20
Many compressor failures are caused by the following
conditions:
1. Improper air flow over the evaporator.
2.
Overcharged refrigerant system causing liquid to be
returned to the compressor.
3.
Restricted refrigerant system.
4.
Lack of lubrication.
5.
Liquid refrigerant returning to compressor causing oil
to be washed out of bearings.
6.
Noncondensables such as air and mois ture in
the system. Moisture is extremely destructive to a
refrigerant system.
Recommended procedure for compressor
replacement
NOTE: Be sure power source is off, then disconnect
all wiring from the compressor.
1.
Be certain to perform all necessary electrical and
refrigeration tests to be sure the compressor is actually
defective before replacing .
2.
Recover all refrigerant from the sys tem though
the pro cess tubes. PROPER HAN DLING OF
RECOVERED REFRIGERANT ACCORDING TO
EPA REGULATIONS IS REQUIRED. Do not use
gauge manifold for this purpose if there has been
a burnout. You will contaminate your manifold and
hoses. Use a Schrader valve adapter and copper
tubing for burnout failures.
3.
After all refrigerant has been recovered, disconnect
suction and discharge lines from the compressor and
remove compressor. Be certain to have both suction
and discharge process tubes open to atmosphere.
4.
Carefully pour a small amount of oil from the suction
stub of the de fec tive com pres sor into a clean
container.
5.
Using an acid test kit (one shot or conventional kit), test
the oil for acid content according to the instructions
with the kit.
6.
If any evidence of a burnout is found, no matter how
slight, the system will need to be cleaned up following
proper procedures.
7.
Install the replacement compressor.
8.
Pressurize with a combination of R-22 and nitrogen
and leak test all connections with an electronic or
Halide leak detector. Recover refrigerant and repair
any leaks found.
9.
Evacuate the system with a good vacuum pump
capable of a final vacuum of 300 microns or less.
The system should be evacuated through both liquid
line and suction line gauge ports. While the unit is
being evacuated, seal all openings on the defective
compressor. Compressor manufacturers will void
warranties on units received not properly sealed. Do
not distort the manufacturers tube connections.
10. Recharge the system with the correct amount of
refrigerant. The proper refrigerant charge will be
found on the unit rating plate. The use of an accurate
measuring device, such as a charging cylinder,
electronic scales or similar device is necessary.
Repeat Step 8 to insure no more leaks are present.
CAPACITORS
Many motor capacitors are internally fused. Shorting the
terminals will blow the fuse, ruining the capacitor. A 20,000
ohm 2 watt resistor can be used to discharge capacitors
safely. Remove wires from capacitor and place resistor
across terminals. When checking a dual capacitor with
a capacitor analyzer or ohmmeter, both sides must be
tested.
Capacitor Check with Capacitor Analyzer
Hazard of shock and electrocution. A capacitor can
hold a charge for long periods of time. A service
technician who touches these terminals can be
injured. Never discharge the capacitor by shorting
across the terminals with a screwdriver.
The capacitor analyzer will show whether the capacitor is
"open" or "shorted." It will tell whether the capacitor is within
its microfarads rating and it will show whether the capacitor
is operating at the proper power-factor percentage. The
instrument will automatically discharge the capacitor when
the test switch is released
Capacitor Connections
The starting winding of a motor can be damaged by a
shorted and grounded running capacitor. This damage
usually can be avoided by proper connection of the running
capacitor terminals.
From the supply line on a typical 230 volt circuit, a 115 volt
potential exists from the "R" terminal to ground through a
possible short in the capacitor. However, from the "S" or
start terminal, a much higher potential, possibly as high as
400 volts, exists because of the counter EMF generated
in the start winding. Therefore, the possibility of capacitor
failure is much greater when the identified terminal is connected to the “S" or start terminal. The identified terminal
should always be connected to the supply line, or "R"
terminal, never to the "S" terminal.
When connected properly, a shorted or grounded running-capacitor will result in a direct short to ground from
the "R" terminal and will blow the line fuse. The motor
protector will protect the main winding from excessive
temperature.
21
ROUTINE MAINTENANCE
NOTE: Units are to be inspected and serviced by qualified service personnel only.
1.
Clean the unit air intake filter at least every 300 to 350 hours of operation. Clean the filters with a mild detergent in
warm water and allow to dry thoroughly before reinstalling.
2.
The indoor coil (evaporator coil), the outdoor coil (condenser coil) and base pan should be inspected periodically
(yearly or bi-yearly) and cleaned of all debris (lint, dirt, leaves, paper, etc.). Clean the coils and base pan with a soft
brush and compressed air or vacuum. If using a pressure washer, be careful not to bend the aluminium fin pack.
Use a sweeping up and down motion in the direction of the vertical aluminum fin pack when pressure cleaning
coils. Cover all electrical components to protect them from water or spray. Allow the unit to dry thoroughly before
reinstalling it in the sleeve.
NOTE: Do not use a caustic coil cleaning agent on coils or base pan. Use a biodegradable
cleaning agent and degreaser.
Inspect the indoor blower housing, evaporator blade, condenser fan blade, and condenser shroud periodically (yearly
or bi-yearly) and clean of all debris (lint, dirt, mold, fungus, etc.) Clean the blower housing area and blower wheel
with an antibacterial / antifungal cleaner. Use a biodegradable cleaning agent and degreaser on condenser fan
and condenser shroud. Use warm or cold water when rinsing these items. Allow all items to dry thoroughly before
reinstalling them.
3.
Periodically (at least yearly or bi-yearly): inspect all control components, both electrical and mechanical, as well
as the power supply. Use proper testing instruments (voltmeter, ohmmeter, ammeter, wattmeter, etc.) to perform
electrical tests. Use an air conditioning or refrigeration thermometer to check room, outdoor and coil operating
temperatures. Use a sling psychrometer to measure wet bulb temperatures indoors and outdoors.
4.
Inspect the surrounding area (inside and outside) to ensure that the units' clearances have not been compromised
or altered.
5.
Inspect the sleeve and drain system periodically (at least yearly or bi-yearly) and clean of all obstructions and debris.
Clean both areas with an antibacterial and antifungal cleaner. Rinse both items thoroughly with water and ensure
that the drain outlets are operating correctly. Check the sealant around the sleeve and reseal areas as needed.
6.
Clean the front cover when needed. Use a mild detergent. Wash and rinse with warm water. Allow it to dry thoroughly
before reinstalling it in the chassis.
Discharge Air Grille
Condenser Fan Blade
Blower Wheel
Indoor Blower Housing
Gasket
Control Door
Outdoor Grille
Condenser
Shroud
Filters
Condenser
Coil
Return Air Grille
Evaporator Coil
Front Cover
22
Control Panel
Compressor
Gasket Basepan
Wall Sleeve
TROUBLESHOOTING CHART — COOLING
REFRIGERANT SYSTEM
DIAGNOSIS COOLING
Low Suction Pressure
High Suction Pressure
Low Head Pressure
High Head Pressure
Low Load Conditions
High Load Conditions
Low Load Conditions
High Load Conditions
Low Air Flow Across
Indoor Coil
High Air Flow Across
Indoor Coil
Refrigerant System
Restriction
Low Air Flow Across
Outdoor Coil
Refrigerant System
Restriction
Reversing Valve not
Fully Seated
Reversing Valve not
Fully Seated
Overcharged
Undercharged
Overcharged
Undercharged
in System
Noncondendsables (air)
Moisture in System
Defective Compressor
Defective Compressor
TROUBLESHOOTING CHART - HEATING
REFRIGERANT SYSTEM
DIAGNOSIS – HEATING
Low Suction Pressure
High Suction Pressure
Low Head Pressure
High Head Pressure
Low Airflow
Across Outdoor Coil
Outdoor Ambient Too High
for Operation in Heating
Refrigerant System
Restriction
Outdoor Ambient Too High
For Operation In Heating
Refrigerant System
Restriction
Reversing Valve not
Fully Seated
Reversing Valve not
Fully Seated
Low Airflow Across
Indoor Coil
Undercharged
Overcharged
Undercharged
Overcharged
Moisture in System
Defective Compressor
Defective Compressor
Non-condensables (air)
in System
23
ELECTRICAL TROUBLESHOOTING CHART - HEAT PUMP
HEAT PUMP
SYSTEM COOLS WHEN
HEATING IS DESIRED.
Is Line Voltage
Present at the Solenoid
Valve?
NO
Is the Selector Switch
Set for Heat?
YES
Is the Solenoid Coil Good?
NO
YES
Reversing Valve Stuck
Replace the Reversing Valve
24
Replace the Solenoid Coil
WIRING DIAGRAM - COOLING WITHOUT ELECTRIC HEAT
25
WIRING DIAGRAM - COOLING WITH ELECTRIC HEAT
26
WIRING DIAGRAM - HEAT PUMP WITH ELECTRIC HEAT
27
FRIEDRICH AIR CONDITIONING CO.
Post Office Box 1540 · San Antonio, Texas 78295-1540
4200 N. Pan Am Expressway · San Antonio, Texas 78218-5212
(210) 357-4400 · FAX (210) 357-4480
www.friedrich.com
Printed in the U.S.A.
P2KPD 1-05

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