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T7984 A,B,C ELECTRONIC MODULATING CONTROL THERMOSTATS 

T7984B 

Output 1 analog

2œ10V 

Output 2

on/off 

Mode input

jumper 

Changeover input 

for Out 1 

Day/Night 

mode (NSB) 

Remote sensor 

option 

75°F setpoint 

limit 

Cooling 

Heating 

Mode A (Jumper out) 

Heating 

Cooling 

Mode B (Jumper in) 

WIRING 

To install a remote duct or room temperature sensor, adjust 

* To enable mode B of operation, install a jumper across the 

DIP switch S6 to 0 = off and wire as shown. 

screw terminals and wire as shown 

Duct 

or 

NSB contact 

from a central timer 

SEQUENCE 

Mode A (jumper not installed) 

Output 1 analog in cooling mode 

Output 2 on/off in heating mode 

Room 

Remote 
sensor input 

(0 Vac) 

NSB input 

SETPOINT DIAL DEFINITION 

HEATING 

End 

SETPOINT

SETPOINT 

Device 

CENTERED 

Output 2 

On/off 

Output 1 

2-10 Vdc 

Mode input 

24 Vac 

Power supply 
(0 Vac) 

Fig. 5. T7984B Wiring 

on 

IN ZERO 

Device

100% 

ENERGY BAND 

opened 

10 Vdc 

50% 

Device 

Device 

closed 

off 

2 Vdc

0% 

OUTPUT 2 

ON/OFF 

OUTPUT 1 

ANALOG 

ZERO ENERGY BAND 

Temperature increase 

Fig. 6. T7984B Sequence (Mode A) 

DIP SWITCH SETTINGS 

DEFINITION 

S3 

S4 

75°F OVERRIDE 

HEATING DIAL 

COOLING DIAL 

CENTERED HC 

SETPOINT DIAL DEFINITION 

ZEB 

S2 

5°F  (3°C) 

3°F  (1.5°C) 


ZERO ENERGY BAND 

CYCLES/HOUR  

S1 

FAST  

8 CPH 

SLOW   4 CPH 

OUTPUT 2 ON/OFF CPH 

ON = 1 

1

2 3 4

5 6

OFF = 0 

COOLING 

SETPOINT 

End 

Input (2-10 Vdc) 
24 Vac 
Common 

2-10 Vdc valve or VAV 
analog actuator 

24 Vac on/off 
relay or valve 

24 Vac Transformer 

Mode B (jumper installed) 

Output 1 analog in heating mode 

Output 2 on/off in cooling mode 

SETPOINT DIAL DEFINITION 

HEATING 

Device 

End 

SETPOINT 

CENTERED 

SETPOINT 

opened 

IN ZERO 

Device

100% 

10 Vdc 

ENERGY BAND 

on 

50% 

Device 

closed 

Device 

2 Vdc 

off 

0% 

OUTPUT 2 

ON/OFF 

ZERO ENERGY BAND 

Temperature increase 

OUTPUT 1 

ANALOG 

Fig. 7. T7984B Sequence (Mode B) 

HEAT SETBACK 

10°F  (5°C) 

5°F  (3°C) 

COOL SETUP 

20°F  (10°C) 

5°F  (3°C) 

S5 


DAY/NIGHT SETBACK 

REMOTE SENSOR 

MAIN SENSOR 

S6 

LOCAL INTERNAL 


0

REMOTE SENSOR 

COOLING 

SETPOINT 

End 

Fig. 8. T7984B Dip Switch Settings 

95C-10815–2 

Summary of Contents for T7984 A

Page 1: ...lve actuators such as ML7285 ML7421 VC7930 or M7410 All models feature user friendly set point knob All models feature output status LEDs for installer check out Locking cover and range stops are standard Night setback models feature selection of two different offset temperatures and use central time switch control Night setback models feature 2 1 2 hour local timed override Heat cool models featu...

Page 2: ...lization SETPOINT RANGE 55 90 F 13 32 C T7984A Heating 55 75 F 13 24 C T7984B C Cooling 75 90 F 24 32 C T7984B C ORDERING INFORMATION The maximum heating setpoint and minimum cooling setpoint is electronically limited to 75 F 24 C REMOTE SENSOR 47 kΩ NTC thermistor part nos 272845 and 272847 ANALOG OUTPUT 2 to 10 Vdc 2 mA max SWITCHED OUTPUT RATING 0 5A running 1 1A inrush 24Vac protected with sel...

Page 3: ...hermostats must be configured for proper operation by setting DIP switches T7984B Reheat output control action 7 5 or 15 minutes T7984B C Zero energy band ZEB 3 F 2 C or 5 F 3 C Setpoint adjustment cooling centred heating centred with limit override for commissioning Night setback amount see Table 2 for complete listing of option settings T7984A B C Main sensor internal or remote Table 3 T7984 DIP...

Page 4: ...act or the changeover sensor across Fig 2 T7984A Wiring Input 2 10 Vdc 24 Vac Common 2 10 Vdc valve or VAV analog actuator Duct or Room Not used Remote sensor input 0 Vac Output 1 2 10 Vdc Changeover input for Out 1 Changeover contact OR Changeover sensor 24 Vac Power supply 0 Vac 24 Vac Transformer SEQUENCE SETPOINT DIAL CENTERED End Heating mode End Opened Cooling mode Device Device changeover 1...

Page 5: ... Device closed off 2 Vdc 0 OUTPUT 2 ON OFF OUTPUT 1 ANALOG ZERO ENERGY BAND Temperature increase Fig 6 T7984B Sequence Mode A DIP SWITCH SETTINGS DEFINITION S3 S4 75 F OVERRIDE 1 1 HEATING DIAL 0 1 COOLING DIAL 1 0 CENTERED HC 0 0 SETPOINT DIAL DEFINITION ZEB S2 5 F 3 C 3 F 1 5 C 1 0 ZERO ENERGY BAND CYCLES HOUR S1 FAST 8 CPH 1 SLOW 4 CPH 0 OUTPUT 2 ON OFF CPH ON 1 1 2 3 4 5 6 OFF 0 COOLING SETPOI...

Page 6: ... valve or VAV analog actuator 24 Vac Transformer Fig 9 T7984C Wiring SEQUENCE SETPOINT DIAL DEFINITION SETPOINT DIAL DEFINITION SETPOINT SETPOINT HEATING COOLING HEATING COOLING SETPOINT CENTERED SETPOINT SETPOINT CENTERED End End Device closed 2 Vdc IN ZERO ENERGY BAND OUTPUT 2 ANALOG OUTPUT 1 ANALOG SETPOINT End IN ZERO End End Device Device 100 ENERGY BAND 100 Device Device opened 10 Vdc 50 End...

Page 7: ...model on how to wire the sensor The remote sensor are not to be used for supply control applications Zero Energy Band T7984B C Thermostats which have cooling and heating outputs T7984B C have 2 distinct setpoints one for heating the other for cooling see the control curves section for each model When the room temperature is between these to setpoints both heating and cooling outputs are off and th...

Page 8: ...ctuator or SCR power controller which is normally used to control terminal reheat in a zone system This type of output on the T7984C uses a half wave rectifier bridge If the same transformer is to be used for the thermostat and the end device be sure to select end devices which also use a half wave rectifier bridge There is a status LED mounted internally that indicates the action of the output Th...

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