White Rodgers 8J48A specifications Wiring and Operation, Volt AC Gas Valve

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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

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Contents Operator Save these instructions for future use Installation InstructionsPrecautions SpecificationsInstallation Dial SettingWell No Description Volt AC Gas Valve Wiring and OperationWiring and Operation cont’d Low Limit-Circulator Control onBoiler with Tankless Domestic Coil

8J48A specifications

The White Rodgers 8J48A is a cutting-edge digital thermostat that has gained recognition for its reliability and efficiency. As a product of White Rodgers, a brand with a longstanding reputation in heating and cooling controls, the 8J48A embodies a range of features and technologies designed to enhance user experience while optimizing energy consumption.

One of the main features of the 8J48A is its simplicity of use. Its intuitive interface includes a clear LCD display, making it easy for users to adjust settings according to their comfort preferences. The thermostat offers a set of programmable options that allow users to customize their heating and cooling schedules based on their daily routines. This programmability not only improves comfort but also contributes significantly to energy savings by reducing unnecessary heating or cooling during unoccupied periods.

In terms of technology, the White Rodgers 8J48A utilizes advanced sensing technology that ensures accurate temperature readings and allows for precise control over indoor climates. This level of accuracy is crucial for maintaining optimal comfort while minimizing energy expenditure. Additionally, the thermostat supports multiple climate control systems, making it versatile and suitable for various HVAC setups, including gas, electric, and heat pump systems.

Another noteworthy characteristic of the 8J48A is its adaptability to different home environments. The thermostat can operate in various modes—such as heating, cooling, and even emergency heat—further enhancing its functionality. The temporary hold feature allows users to override programmed temperatures for a limited time without having to reprogram the entire schedule. This is particularly useful for unexpected changes in routine or short-term events.

Moreover, the White Rodgers 8J48A is equipped with a battery backup feature, ensuring that its settings remain intact in the event of a power outage. This reliability is key for homeowners who prioritize consistent indoor climate control.

Overall, the White Rodgers 8J48A digital thermostat stands out due to its combination of user-friendly features, advanced technology, and adaptability to various heating and cooling systems. It represents a smart investment for homeowners looking for an efficient and convenient way to manage their indoor temperatures while achieving energy savings. Whether through its programming capabilities or its ease of use, the 8J48A exemplifies what modern thermostats can offer in terms of comfort and efficiency.