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T7984 A,B,C ELECTRONIC MODULATING CONTROL THERMOSTATS 

T7984A 

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 and/or 

heating 

WIRING 

To install a remote duct or room temperature sensor, adust DIP 

the screw terminals and wire as shown. 

switch S6 to 0 = off and wire as shown. 

(If sensor is used, wire 1changeover sensor per 

To reverse operation of output 1 to heating, install the 

thermostat.) 

changeover contact 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

100% 

opened 

opened

input active 

10 Vdc 

10 Vdc 

50% 

End 

0% 

Closed 

End 

Device 

closed 

closed 

Device 

Temperature increase 

OUTPUT 1 ANALOG 

Fig. 3. T7984A Sequence 

DIP SWITCH SETTINGS 

REMOTE SENSOR 

MAIN SENSOR 

S6 

LOCAL INTERNAL 

REMOTE SENSOR  0 

<< Not used 

ON = 1 

OFF = 0  6 7 8 

Fig. 4. T7984A 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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