White Rodgers 8J48A User Manual

WHITE-RODGERS

Operator: Save these instructions for future use!

FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY
BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE
PERSONAL INJURY AND/OR PROPERTY DAMAGE.

These relay-hot water controls combine a high limit control, a
transformer, a circulator relay, and wiring terminals into a single
unit. They are suitable for use on boilers equipped with a 24 volt
or millivolt gas valve.

These controls are designed primarily for use on boilers that do
not supply domestic hot water. (However, they are equipped
with an extra terminal to permit them to be used on boilers with
a tankless domestic coil by the addition of a separate SPDT low
limit-circulator control on systems using a 24 volt gas valve.)

The internal transformer supplies power for operating a gas
valve as well as the relay coil. On systems zones with motorized
water valves, the internal transformer may also be used for
powering some (or all) of the water valves.

8J48A

Relay-Hot Water Control

For use with 24 VAC or Self-Generating Gas Valve

(Suitable for External Zone Valve Load)

INST ALLA TION INSTRUCTIONS

DESCRIPTION

If in doubt about whether your wiring is millivolt, line, or low
voltage, have it inspected by a qualified heating and air condi­tioning contractor, electrician, or someone familiar with basic
electricity and wiring.

Do not exceed the specification ratings.
All wiring must conform to local and national electrical codes

and ordinances.
This control is a precision instrument, and should be handled

carefully. Rough handling or distorting components could cause
the control to malfunction.

ELECTRICAL RATINGS
Input Voltage: 120 VAC, 60 Hz
Circulator Motor: 8.0 Amps Full Load Current (120 VAC)

48.0 Amps Locked Rotor Current (120 VAC)

Gas Valve: 24.0 VAC, 0.65 Amp OR

Millivolt Systems (0.25 to 1.0 VDC, 0.25 Amp)

Combined Load of Zone Valves:

Internal transformer (terminals TV and Z) may be used for
supplying power to four W-R Type 1311 or three Type 1361
zone Valves. (For other zone valves, total zone valve load is not
to exceed 1.2 Amp.)

PRECAUTIONS

CAUTION

!

To prevent electrical shock and/or equipment damage,
disconnect electric power to system, at main fuse or
circuit breaker box, until installation is complete.

WARNING

!

Do not use on circuits exceeding specified voltage.
Higher voltage will damage control and could cause
shock or fire hazard.

Do not short out terminals on gas valve or primary
control to test. Short or incorrect wiring will burn out
heat anticipator. Personal injury and/or property dam­age may result from shorted or incorrect wiring.

SPECIFICATIONS

ROOM THERMOSTAT

Set adjustable heater (anticipator) at 0.25, or use a fixed heater
with a 0.25 Amp rating.

HOT WATER CONTROLS
Range: High Limit – 140° to 240°F. (Some models have a

Preset Dial Stop. Adjustments should be made by
authorized service personnel only.)

Differential: High Limit – 8°F Fixed
Switch Action: High Limit – Open on rise

WHITE-RODGERS DIVISION

EMERSON ELECTRIC CO.
9797 REAVIS ROAD
ST. LOUIS, MISSOURI 63123-5398

Printed in U.S.A.

PART NO. 37-4013C

Replaces 37-4013B

9522

INSTALLATION

NOTE

If the boiler manufacturer recommends a control location, then
follow such recommendations. Otherwise, locate the control as
close to the top of the boiler as possible, but not in the same
section of the boiler that has fittings for domestic hot water.
Never locate the control near a return pipe to the boiler.

PREPARING TO MOUNT CONTROL

This control can be mounted vertically or horizontally.

1. Loosen the set-screw holding the well in place (see fig. 1).

2. Push down and out on the well and carefully slide the
capillary tube in slot.

3. Place the well in new notch and tighten the set-screw to
secure the well in the new position.

MOUNTING THE CONTROL

1. Disconnect electrical power to the boiler.

2. Completely drain the boiler.

3. If a well tapping is not provided, prepare one near the top of
the boiler.

4. Sparingly apply pipe joint compound to the well threads and
install well.

NOTE

Use hex on well for tightening the well. Do not attempt to tighten
by using the case as a handle.

5. Refill the boiler and check for water leaks.

6. Insert the bulb element into the well until it bottoms.

7. Locate and secure the coil of excess tubing so that it cannot
touch electrical components.

8. Fit the back of the case into the well and tighten using the set­screw on the back panel.

Slot

Capillary

Tube

Well

Set-screw

Figure 1

MOUNTING TO EXISTING WELL

(For use with well adaptor, which may be ordered separately.)
For best control performance, a well comparable to that shown

in fig. 2 is recommended. However, by using a heat conductive
grease, these controls will give satisfactory performance when
used with large-diameter existing wells. If desired, both the
conductive grease and replacement wells may be ordered
separately (see fig. 2).

C

AB

Well No. Description A B C

89-0211
89-0212
89-0213
89-0214
89-0215

Conductive Grease No. 145-0163

1

⁄2” Std. Shank

1

⁄2” Std. Ext. Shank

3

⁄4” Std. Shank

3

⁄4” Std. Ext. Shank

3

⁄4” Extra Ext. Shank

13

⁄16”

1

5

3

⁄16”

13

1

⁄16”

5

3

⁄16”

13

4

⁄16”

3”
3”
3”
3”
3”

5

3

⁄16”

5

3

⁄16”

5

3

⁄16”

5

3

⁄16”

5

3

⁄16”

DIAL SETTING

When replacing an existing control, adjust the setting of the high
limit to correspond with that of the old control.

Set the pointer to the temperature at which the contacts of the
high limit are to open (see fig. 3)

Models with a preset dial stop are to be adjusted by authorized
service personnel only.

To reset the dial stop, loosen the stop adjust screw and reposi­tion the stop to the desired setting.

Retighten the stop adjust screw.

WARNING

!

DO NOT set the stop higher than the original
manufacturer’s recommended setting. Personal injury
and/or property damage may result.

2

Figure 2

140

160 220

200180

Figure 3

Stop

Stop
Adjust
Screw

Pointer

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 ener­gized 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.

Transformer

No. 2 Relay

Contacts

Hot

C1

L1

120 VAC

Room Thermostat

L2

Neutral

C2

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.

Factory­installed

Jumper

Z W TP

Low Voltage

Field-

installed

Jumper

T

TV

Manual

Switch

High
Limit

B

No. 1 Relay

Contacts

36C

Gas Valve

TH TH-TR TR

B2

INTERNAL WIRING

EXTERNAL WIRING

Hot

L1

120 VAC

L2

Neutral

INTERNAL WIRING

Line Voltage
Low Voltage

EXTERNAL WIRING

Line Voltage
Low Voltage

Line Voltage
Low Voltage

Line Voltage
Low Voltage

C1

C2

No. 2 Relay

Contacts

Circulator

Motor

Figure 4. 24 Volt AC Gas Valve

Factory­installed

Transformer

Jumper

Z W TP

Low Voltage

Room Thermostat

Circulator

Motor

Figure 5. Millivolt Gas Valve

T

TV

B3

B3

Manual

Switch

No. 1 Relay

Contacts

B2

High
Limit

B

36C

Gas Valve

TH TH-PG PG

B1

To 750 MV
Thermopile

B1

3

WIRING AND OPERATION (cont’d)

Figure 7. Alternate Connections for using Separate

Low Limit-Circulator Control on

Boiler with Tankless Domestic Coil

Z

BL

W

RWB

Low Limit
Circulator

Control

NOTE: Remove external jumper

between W and Z terminals

Thermostat

8J48A

W-R
1361
Zone

Valves

2

13

TV

Z

24V
Gas

Valve

T

B3B1

Hot

Figure 6. Typical Connections for

Zoning with 2-Wire Zone Valves

LINE

C2C1

L2L1

Neutral

Circulator

Motor

Line Voltage
Low Voltage

36C Series

Gas Valve

Thermostat

Zone 1

Factory­Installed

Jumper

TR TH-TR TH

TWTV

B1 B2 B3 L1 L2

BZTP

8J48A

C1

C2

Thermostat

829A

Relay

Circulator

Zone 1

Zone 2

531

246

Circulator

Field-

Installed

Jumper

Zone 2

Figure 8. 8J48A - 24 Volt Systems Zoned with Circulators

Thermostat

Zone 1

Thermostat

Zone 2

829A

Relay

Thermostat

Zone 3

531

24

6

Circulator

Thermostat

Zone 3

Field-

Installed

Jumper

Zone 3

Neutral

120 V

Hot

TWTV

B1

B2 B3 L1 L2

Factory­Installed

Jumper

To 750 MV
Thermopile

Line Voltage
Low Voltage

36C Series

Gas Valve

PG TH-PG TH

Figure 9. 8J48A - Millivolt Systems Zoned with Circulators

BZTP

8J48A

C1

C2

829A

Relay

Circulator

Zone 1

531

246

Circulator

Field-

Installed

Jumper

Zone 2

829A

Relay

531

24

6

Circulator

Field-

Installed

Jumper

Zone 3

Neutral

120 V

Hot