White Rodgers 8J48A specifications Wiring And Operation, Auto/Manual Switch, 24 Volt AC Gas Valve

WIRING AND OPERATION

All wiring should be installed according to local and national electrical codes and ordinances.

Figure 4 shows wiring connections for a typical installation using the 8J48A with a 36C03 or a 36C53 24V manifold gas valve. Figure 5 shows wiring connections for the 8J48A with a 36C03U or 36C53U self-generating gas valve. Operation is as follows: As the room thermostat contacts close, the relay coil is ener- gized and closes its two sets of relay contacts. The manifold gas valve opens as the no. 1 relay contacts close, while the circulator motor starts as the no. 2 relay contacts close.

When the room thermostat opens its contacts, the manifold gas valve closes and the circulator motor stops.

If the boiler temperature exceeds the setting of the high limit while the thermostat is calling for heat, the high limit will close the gas valve but permit the circulator to run as long as the thermostat is calling for heat.

AUTO/MANUAL SWITCH

NOTE

For manual operation of self-generating millivolt systems only.

The manual switch, located on the outside of the controls case, allows operation of the burner during power failures. When the switch is set to MANUAL, the burner will operate continuously until the high limit temperature is reached. The circulator, which requires line voltage to operate, will not function in MANUAL mode. When power is restored, reset the switch to AUTO to resume automatic operation.

Hot

L1

120 VAC

L2

Neutral

No. 2 Relay

Contacts

C1

C2

Factory-		Field-	Manual
installed		installed	Switch
Jumper		Jumper	High
Transformer			Limit
Z	W	TP	B
			No. 1 Relay
			Contacts

Low Voltage	36C
Room Thermostat
	Gas Valve
T
	TH TH-TR TR
TV	B2

B3 B1

INTERNAL WIRING

Line Voltage

Low Voltage

EXTERNAL WIRING

Line Voltage

Low Voltage

Circulator

Motor

Figure 4. 24 Volt AC Gas Valve

Hot

L1

120 VAC

L2

Neutral

INTERNAL WIRING Line Voltage

No. 2 Relay

Contacts

C1

C2

Factory-			Manual
installed			Switch
Jumper			High
Transformer			Limit
Z	W	TP	B
			No. 1 Relay
			Contacts

Low Voltage		36C	To 750 MV
Room Thermostat			Thermopile
		Gas Valve
	T
		TH TH-PG PG

TV

B3 B2

B1

Low Voltage

EXTERNAL WIRING

Line Voltage

Low Voltage

Circulator

Motor

Figure 5. Millivolt Gas Valve

3