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T6984F,G
Electronic Floating
Control Thermostats
PRODUCT DATA
FEATURES
• P+I control action provides accurate, stable room temperature control.
• Used with ML6144 Series 60 Direct Coupled Damper
Actuators.
• User-friendly set point knob.
• Output status LED for installer check-out.
• Can drive up to four (4) ML6144 Actuators.
• Fixed actuator timing at 8.4 minutes.
APPLICATION
These microprocessor-based thermostats provide proportional-plus-integral individual room control in underfloor air delivery systems. They are used with the Honeywell
ML6144A Actuator.
® U.S. Registered Trademark
Copyright © 2002 Honeywell • All Rights Reserved
Contents
Application ........................................................................
Features ...........................................................................
Specifications ...................................................................
Ordering Information ........................................................
2
Installation ........................................................................
Operation ..........................................................................
Checkout ..........................................................................
63-2585-2
T6984F,G ELECTRONIC FLOATING CONTROL THERMOSTATS
SPECIFICATIONS
IMPORTANT
The specifications given in this publication do not include normal manufacturing tolerances. Therefore, this unit may not exactly match the listed specifications. Also, this product is tested and calibrated under closely controlled conditions, and some minor differences in performance can be expected if those conditions are changed.
Models: See Table 1.
Table 1. T6984 Models.
Model
Output
1
Main
Temperature
Sensor
T6984F floating internal
Output
2
—
T6984G floating internal
Output
—
3
Night
Setback
— on/off on/off dry contact
Dimensions: See Fig. 1.
Mounting: Mounts to single-gang NEMA-standard 2 in. x 4 in. electrical box, or directly to wall. Requires 1-1/8 in.
(35 mm) access hole for wiring.
Wiring: Four (T6984F) and eight (T6984G) 1/8 in. screw terminals suitable for 2 no.18 AWG (1 mm
2
) wires each.
Power Supply: 19 - 30 Vac, 50/60 Hz, 2 VA, Class 2.
(Does not include actuator power requirements.)
Operating Ambient: 32-104°F (0-40°C) at 5-95% RH
(non-condensing).
Setpoint Range:
Scale marked with +/- scale only, for warmer/cooler indication.
With no range stops installed 55 - 90°F (13 - 32°C).
With factory installed range stops 65 - 80°F (18 - 27°C).
Switched Output Rating:
Output 1 floating: 24 Vac, 1.0A maximum running, 1.1A inrush.
The thermostat can directly drive up to four ML6144A
Actuators maximum.
Outputs 2 and 3 reheat (T6984G only): 24 Vac 0.5A maximum running, 1.1 A inrush.
Outputs are protected with self-resetting circuit interrupter.
Accuracy: 1°F (0.4°C).
Precision: ±0.5°F (0.4°C).
Approvals:
Designed for Class II low voltage installation only.
Case and cover meet UL94-5V flammability requirements, and North American codes for line voltage thermostat enclosures.
Meets requirements of F.C.C. Part 15 Class B, IEC 801-3 for
CE.
radio frequency interference.
Accessories:
272846 Adapter Plate for British standard, European, doublegang NEMA electrical boxes, or for surface mounting.
M20026
3-3/16 (81)
SYSTEM
1-9/16
(39)
3/16 (5)
4-3/4
(120)
BUTTON
SWITCH
1-9/16 (39)
Fig. 1. Dimensions in in. (mm).
3/16
(5)
3-3/16
(81)
11/16
(17)
ORDERING INFORMATION
When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the
TRADELINE® Catalog or price sheets for complete ordering number.
If you have additional questions, need further information, or would like to comment on our products or services, please write or phone:
1. Your local Home and Building Control Sales Office (check white pages of your phone directory).
2. Home and Building Control Customer Relations
Honeywell, 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386
In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9.
International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France,
Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.
63-2585—2 2
INSTALLATION
Location
Install the thermostat about 4 ft. (1.2m) above the floor in an area with good air circulation at average temperature conditions.
Do not install thermostat where it can be affected by:
— drafts, or dead air spots behind doors and in corners.
— hot or cold air from ducts.
— radiant heat from sun or appliances.
— concealed pipes and chimneys.
— unheated (cooled) areas such as an outside wall behind the thermostat.
Mounting
The thermostat can be mounted directly on the wall with or without a wallplate or a standard single gang electrical box, or double gang with 272846 Adapter Plate.
CAUTION
Electrical Shock or Equipment Damage Hazard.
Can shock individuals or short equipment circuitry.
Disconnect power supply before installation.
Wiring
CAUTION
Equipment Damage Hazard.
Ground loops can short equipment circuitry.
Avoid grounding all transformer secondaries (low voltage sides).
Typical wiring connections are shown in Fig. 2 through 5.
Wiring connections can be made to the screw terminal block with 2-18AWG or 1-14AWG, solid or stranded copper wires.
Connect the system wires to the thermostat terminals. Push excess wire back into hole. Plug hole to prevent drafts.
T6984F,G ELECTRONIC FLOATING CONTROL THERMOSTATS
T6984G
4
OUTPUT 3
OUTPUT 2
3
OPEN
CLOSE
M6144
OPEN
CLOSE
COMMON
2
4
5
0 VAC
NSB INPUT
24 VAC
0 VAC
L2
1
L1
(HOT)
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2 A MAXIMUM OF FOUR ML6144 ACTUATORS CAN BE CONNECTED TO
ONE T6984G CONTROLLER (WHEN CONNECTED EITHER DIRECTLY
OR THROUGH A 32003967-001 POWER CONTROL MODULE).
3 OUTPUT 1.
4 24 VAC RELAY OR VALVE.
5 NSB CONTACT FROM A CENTRAL TIMER.
M20031
Fig. 3. Typical T6984G wiring.
2
0 VAC
NSB INPUT
0 VAC
NSB INPUT
0 VAC
NSB INPUT
T6984G
24 VAC
0 VAC
T6984G
24 VAC
0 VAC
T6984G
24 VAC
0 VAC
L2
L1
1
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2 NSB CONTACT FROM A CENTRAL TIMER.
M20048
Fig. 4. Wiring multiple T6984G Thermostats with a single transformer.
T6984F
OPEN
M6144 2
CLOSE
24 VAC
OPEN
CLOSE
COMMON
0 VAC
L1
(HOT)
L2
1
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2 A MAXIMUM OF FOUR ML6144 ACTUATORS CAN BE CONNECTED TO
ONE T6984F CONTROLLER (WHEN CONNECTED EITHER DIRECTLY
OR THROUGH A 32003967-001 POWER CONTROL MODULE).
M20034
Fig. 2. T6984F wiring.
2
0 VAC
NSB INPUT
0 VAC
NSB INPUT
0 VAC
NSB INPUT
T6984G
24 VAC
0 VAC
T6984G
24 VAC
0 VAC
T6984G
24 VAC
0 VAC
L2
L1
1
L2
L1
1
L2
L1
1
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2 NSB CONTACT FROM A CENTRAL TIMER.
M20049
Fig. 5. Wiring multiple T6984G Thermostats with individual transformers.
3 63-2585—2
T6984F,G ELECTRONIC FLOATING CONTROL THERMOSTATS
OPERATION
NOTE: The output electronic contacts (triacs) are protected with a self-resetting circuit interrupter. In the event of an overload or short circuit, the self-resetting interrupter reduces the load to a very low level. If power is removed or the overload or short circuit disappears, then the circuit interrupter returns to its normal condition and allows normal operation.
Output 1 Proportional Tri-state Floating
The main thermostat output is a P+I modulating floating type signal that uses a set of two, 24 Vac non-isolated electronic contacts to control the floating damper actuator(s). One contact to open the end device, the other to close the end device. The actuator will open and close to multiple positions according to demand. When demand and temperature are satisfied, the thermostat stops moving the actuator, leaving it at its last position until the demand changes (see Fig. 6).
— The internal green LED indicates that the actuator is opening or opened.
— The internal yellow LED indicates the actuator is closing or closed. See Table 6.
On power-up, the close output is energized for 8.4 minutes to synchronize all actuators. After this, normal control operation resumes. Every 21.5 hours, the synchronization process is repeated.
SETPOINT DIAL
CENTERED
100%
(FULLY
OPEN)
50%
0%
(FULLY
CLOSED)
TEMPERATURE RISE
COOLING
ONLY
MODE
OUTPUT 1
(FLOATING)
HEATING
ONLY
MODE
M20025
Fig. 6. T6984F sequence.
Temperature Differential (T6984G only)
The T6894G thermostat has two distinct setpoints, one for heating, the other for cooling (see Fig. 3). When the room temperature is between these setpoints, neither heating nor cooling are working and the room temperature is in the
Differential. When room temperature drops below the heating setpoint, Output 2 energizes. When room temperature rises above the cooling setpoint, Output 1 energizes.
Two values are available for the Differential: 2°F (1°C) and
5°F (3°C). The value can be adjusted with the dip switch (S2).
Output 2 and 3 On/Off (T6984G only)
24 Vac on/off outputs which are normally used to control reheat in a zoned system. Example: electric baseboard or duct heater relay, on/off 24 Vac hydronic valve, etc.
Three different control sequences are offered:
• Binary (see Fig. 7 and Table 2).
• Fan and one heating step (see Fig. 8): Fan runs whenever there is heating demand.
• Two heating steps (see Fig. 9): Use the fan as heating stage and cycle it more often. This sequence is used when return plenum air is hot enough to be used as a primary heating stage.
NOTE: All control sequences use Output 1 for floating control of cooling.
The internally-mounted status LED indicates the output action. The red LED indicates that the output electronic contact (triac) is energized.
On
Off
On
Table 2. Binary Control Sequence.
Output 2
Off
On
On
Output 3 Start a
Fan b
Stage 1 heat (fan on) c
Stage 2 heat (fan and stage 1 heat on) a The stages/fan turn off in the reverse order that they turn on
(see Fig. 7).
b
The Fan must be on in order for Stage 1 to turn on.
c
Stage 1 heat must be on for Stage 2 to turn on.
Cycles Per Hour (CPH)
It is possible to fix the number of times per hour the reheat end device energizes. Those settings are adjusted with a dip switch (S1). Two different settings are possible: 4 CPH and
8 CPH. However, the CPH switch (S1) modifies only certain outputs depending on the sequence selected (see Table 3).
Table 3. Cycles Per Hour.
2 heating step sequence
Output 2
Binary sequence No
Fan and 1 heating step sequence
No (Fan output)
Yes (S1 applies)
No
Output 3
Yes (S1 applies)
Yes (S1 applies)
63-2585—2 4
T6984F,G ELECTRONIC FLOATING CONTROL THERMOSTATS
STAGE
3 ON
TRUE HEATING
SETPOINT
1
TRUE COOLING
SETPOINT
STAGE
3 OFF
STAGE
2 ON
STAGE
2 OFF
STAGE
1 ON
STAGE
1 OFF
TEMPERATURE
OUTPUTS
2 AND 3
DIFFERENTIAL
TEMPERATURE
RISE
OUTPUT 1
(FLOATING)
1 DIAL SETPOINT CENTERED IN DIFFERENTIAL.
100%
(FULLY
OPEN)
50%
0%
(FULLY
CLOSED)
M20027
Fig. 7. T6984G binary heat control sequence
(Output 2 and 3 binary heating mode).
OUTPUT 3 ON
TRUE HEATING
SETPOINT
1
TRUE COOLING
SETPOINT
100%
(FULLY
OPEN)
2
OUTPUT 3
OFF
50%
OUTPUT 3 ON
TRUE
HEATING
SETPOINT
1
TRUE
COOLING
SETPOINT
100%
(FULLY
OPEN)
2
OUTPUT 3
OFF
50%
2
OUTPUT 2 ON
OUTPUT 2
OFF
0%
(FULLY
CLOSED)
DIFFERENTIAL
TEMPERATURE
RISE
OUTPUT 3 OUTPUT 2
OUTPUT 1
(FLOATING)
1 DIAL SETPOINT CENTERED IN DIFFERENTIAL.
2 SELECTABLE CYCLES PER HOUR (CPH): 4 OR 8.
M20029
Fig. 9. T6984G heat control sequence 3: 2 heating steps
(Outputs 2 and 3 time proportioning heat).
FAN
ON
FAN
OFF
0%
(FULLY
CLOSED)
OUTPUT 3
FAN (OUTPUT 2)
DIFFERENTIAL
TEMPERATURE
RISE
OUTPUT 1
(FLOATING)
1 DIAL SETPOINT CENTERED IN DIFFERENTIAL.
2 SELECTABLE CYCLES PER HOUR (CPH): 4 OR 8.
M20028
Fig. 8. T6984G heat control sequence 2: Fan, 1 stage heat
(Output 2 on/off fan; Output 3 time proportioning heat).
5 63-2585—2
T6984F,G ELECTRONIC FLOATING CONTROL THERMOSTATS
Night Setback Day/Night Modes (T6984G only)
An energy saving mode by which the actual setpoints are modified to different values than the ones adjusted on the dial. The cooling setpoint increases, the heating setpoint decreases. This mode is energized with a dry contact from a remote time clock.
Two different setup and setback values are adjustable with a
DIP switch (see Fig. 10 and Table 4).
SWITCH
1 2 3 4 5
ON = 1
OFF = 0
M20032
Fig. 10. DIP switch definitions.
0
1
0
Table 4. DIP Switch Settings.
0
1
Switch
Position
Switch 1 Switch 2 Switch 5
Day/Night Setback
Binary
Cycling
4 CPH
Differential Heating Cooling
2°F (1°C) 5°F (3°C) 5°F (3°C)
8 CPH 5°F (3°C) 10°F (6°C) 20°F (11°C)
Switch 3
0
1
1
Switch 4
Binary
Reheat Sequence
Fan and 1 Heating Step
2 Heating Steps
NOTES:
— The system LED on this thermostat cover flashes to indicate that it is in night mode.
— Override night setback temporarily (2-1/2 hours) by depressing the override button (on the cover).
— Press the button again to fully restore thermostat setpoints to day mode.
— One night setback timer contact can be used for multiple thermostats.
63-2585—2 6
T6984F,G ELECTRONIC FLOATING CONTROL THERMOSTATS
CHECKOUT
Service LED
All thermostats have internal service LED lights and a system status LED on the cover. The internal service LED are colored lights that can be viewed from the thermostat side when they are energized. The system status LED is mounted on the cover. (See the checkout and start up procedures section in the Application Manual.)
Thermostat operation can be confirmed with the thermostat cover system and service status LED (see Table 5).
Model
T6984F
T6984G
Table 5. System Status LED.
Color
Green
Red
Explanation
High Intensity = Demand for cooling.
Low = no demand
Flashing = night setback and setup activated
Table 6. Internal Service LED.
F G Color Indication
X X Green Actuator/valve opening
X X Yellow Actuator/valve closing
X Red 2 On/Off output 2 is closed. Load energized.
X Red 3 On/Off output 3 is closed. Load energized.
Test Condition (T6984G only)
Table 7. T6984G Test Condition.
Rotate Knob to
Minimum Position (-)
Green Yellow
On
Maximum Position (+) Off
Off
On
Red 2
Reheat
Off
On
Red 3
Reheat
Off
On
Power-up Sequence
When power is first applied to the thermostat, a 24V pulse equal to the actuator travel time is applied to the actuator to bring it to the fully closed position. This synchronizing sequence is required as the thermostat has no way of knowing the actuator position. Once the actuator is closed, the pulses to the actuator are synchronized with the actuator position. The thermostat then positions the actuator exactly, using timed voltage pulses.
IMPORTANT
The thermostat will not respond to setpoint demands until this reset sequence is complete.
NOTES:
— On power-up, the close output is energized for
8.4 minutes to synchronize all actuators, then normal control operation resumes.
— If the box reaches fully open or closed position
(based on timing), actuators are de-energized.
— Every 21.5 hours, a synchronization process
(by closing the box) is repeated.
7 63-2585—2
By using this Honeywell literature, you agree that Honeywell will have no liability for any damages arising out of your use or modification to, the literature. You will defend and indemnify Honeywell, its affiliates and subsidiaries, from and against any liability, cost, or damages, including attorneys’ fees, arising out of, or resulting from, any modification to the literature by you.
Automation and Control Solutions
Honeywell Honeywell Limited-Honeywell Limitée
1985 Douglas Drive North
Golden Valley, MN 55422
35 Dynamic Drive
Scarborough, Ontario
M1V 4Z9
63-2585—2 B.B. Rev. 6-02
Printed in U.S.A. on recycled paper containing at least 10% post-consumer paper fibers.
www.honeywell.com
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Table of contents
- 1 Application
- 1 Features
- 2 Specifications
- 3 Installation
- 3 Location
- 3 Mounting
- 3 Wiring
- 4 Operation
- 4 Output 1 Proportional Tri-state Floating
- 4 Temperature Differential (T6984G only)
- 4 Output 2 and 3 On/Off (T6984G only)
- 4 Cycles Per Hour (CPH)
- 6 Night Setback Day/Night Modes (T6984G only)
- 7 Checkout
- 7 Service LED
- 7 Test Condition (T6984G only)