White Rodgers 8J48A User manual

Printed in U.S.A. PART NO. 37-4013C
Replaces 37-4013B
9522
8J48A
Relay-Hot Water Control
For use with 24 VAC or Self-Generating Gas Valve
(Suitable for External Zone Valve Load)
INSTALLATION INSTRUCTIONS
DESCRIPTION
These relay-hot water controls combine a high limit control, a
transformer,acirculatorrelay,andwiringterminalsintoasingle
unit.Theyaresuitableforuseonboilersequippedwitha24volt
or millivolt gas valve.
Thesecontrols aredesignedprimarily for useon boilers thatdo
not supply domestic hot water. (However, they are equipped
with an extra terminal to permit them to be used on boilers with
atanklessdomesticcoilbytheadditionof aseparateSPDTlow
limit-circulator control on systems using a 24 volt gas valve.)
The internal transformer supplies power for operating a gas
valveaswellastherelaycoil.Onsystemszoneswithmotorized
water valves, the internal transformer may also be used for
powering some (or all) of the water valves.
WHITE-RODGERS DIVISION
EMERSON ELECTRIC CO.
9797 REAVIS ROAD
ST. LOUIS, MISSOURI 63123-5398
WHITE-RODGERS
FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY
BEFOREINSTALLINGOROPERATINGTHISCONTROLCOULDCAUSE
PERSONAL INJURY AND/OR PROPERTY DAMAGE.
Operator: Save these instructions for future use!
To prevent electrical shock and/or equipment damage,
disconnect electric power to system, at main fuse or
circuit breaker box, until installation is complete.
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 dam-
age may result from shorted or incorrect wiring.
SPECIFICATIONS
PRECAUTIONS
CAUTION
!
WARNING
!
If in doubt about whether your wiring is millivolt, line, or low
voltage, have it inspected by a qualified heating and air condi-
tioning 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.Roughhandlingordistortingcomponentscouldcause
the control to malfunction.
ELECTRICAL RATINGS
Input Voltage: 120 VAC, 60 Hz
Circulator Motor: 8.0 Amps Full Load Current (120 VAC)
48.0AmpsLockedRotorCurrent(120VAC)
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
zoneValves.(Forotherzonevalves,totalzonevalveloadisnot
to exceed 1.2 Amp.)
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

2
INSTALLATION
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.
Usehex onwellfor tighteningthewell. Donotattempt totighten
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. Fitthebackofthecaseintothewellandtightenusingtheset-
screw on the back panel.
NOTE
NOTE
Figure 1
Slot
Well
Set-screw
Capillary
Tube
,


AB
C
1
⁄
2
” Std. Shank
1
⁄
2
” Std. Ext. Shank
3
⁄
4
” Std. Shank
3
⁄
4
” Std. Ext. Shank
3
⁄
4
” Extra Ext. Shank
1
13
⁄
16
”
3
5
⁄
16
”
1
13
⁄
16
”
3
5
⁄
16
”
4
13
⁄
16
”
3”
3”
3”
3”
3”
3
5
⁄
16
”
3
5
⁄
16
”
3
5
⁄
16
”
3
5
⁄
16
”
3
5
⁄
16
”
89-0211
89-0212
89-0213
89-0214
89-0215
Conductive Grease No. 145-0163
Well No. Description A B C
Figure 2
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).
DIAL SETTING
Whenreplacinganexistingcontrol,adjustthesettingofthehigh
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 reposi-
tion the stop to the desired setting.
Retighten the stop adjust screw.
DO NOT set the stop higher than the original
manufacturer’srecommended setting.Personal injury
and/or property damage may result.
WARNING
!
140
160 220
200180
Stop
Stop
Adjust
Screw
Pointer
Figure 3

3
WIRING AND OPERATION
All wiring should be installed according to local and national electrical codes and ordinances.
Figure4showswiringconnectionsforatypicalinstallationusing
the 8J48A with a 36C03 or a 36C53 24V manifold gas valve.
Figure5showswiringconnectionsforthe8J48Awitha36C03U
or 36C53U self-generating gas valve. Operation is as follows:
As the room thermostat contacts close, the relay coil is ener-
gizedandclosesitstwosetsofrelaycontacts.Themanifoldgas
valveopensastheno.1relaycontactsclose,whilethecirculator
motor starts as the no. 2 relay contacts close.
Whenthe room thermostat opensitscontacts, the manifold gas
valve closes and the circulator motor stops.
If the boiler temperature exceeds the setting of the high limit
whilethethermostatiscallingforheat,thehighlimitwillclosethe
gas valve but permit the circulator to run as long as the
thermostat is calling for heat.
AUTO/MANUAL SWITCH
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
untilthe high limit temperature isreached.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.
NOTE
C1
C2 T
TV
B3 B1
Z W TP
B2
B
120 VAC
Transformer
Factory-
installed
Jumper
Field-
installed
Jumper
Manual
Switch High
Limit
No. 1 Relay
Contacts
36C
Gas Valve
Low Voltage
Room Thermostat
Circulator
Motor
No. 2 Relay
Contacts
Hot
Neutral
TH TH-TR TR
Line Voltage
Low Voltage
INTERNAL WIRING
Line Voltage
Low Voltage
EXTERNAL WIRING
Figure 4. 24 Volt AC Gas Valve
L1
L2
C1
C2 T
TV
B3
Z W TP
B2
B
120 VAC
Transformer
Factory-
installed
Jumper
Manual
Switch High
Limit
No. 1 Relay
Contacts
36C
Gas Valve To 750 MV
Thermopile
Low Voltage
Room Thermostat
Circulator
Motor
No. 2 Relay
Contacts
Hot
Neutral
TH TH-PG PG
Line Voltage
Low Voltage
INTERNAL WIRING
Line Voltage
Low Voltage
EXTERNAL WIRING
Figure 5. Millivolt Gas Valve
L1
L2
B1

WIRING AND OPERATION (cont’d)
Circulator
Motor
8J48A
Thermostat
L2L1
C2C1
Figure 6. Typical Connections for
Zoning with 2-Wire Zone Valves
B3B1
TV
Z
24V
Gas
Valve
Hot
LINE
W-R
1361
Zone
Valves
Neutral
T
13
2
Figure 7. Alternate Connections for using Separate
Low Limit-Circulator Control on
Boiler with Tankless Domestic Coil
Z
BL
W
R
W
BLow Limit
Circulator
Control
NOTE: Remove external jumper
between Wand Zterminals
Circulator
Zone 1 Circulator Zone 2
8J48A
829A
Relay 829A Relay
Figure 8. 8J48A - 24 Volt Systems Zoned with Circulators
Thermostat
Zone 2
B1 B2 B3 L1 L2
C1
BZTP
TWTV
C2
36C Series
Gas Valve
Factory-
Installed
Jumper
Field-
Installed
Jumper
TR TH-TR TH
Field-
Installed
Jumper
Thermostat
Zone 1
531
246
Thermostat
Zone 3
531
24
120 V
6
Circulator
Zone 3
Neutral
Hot
Line Voltage
Low Voltage
Circulator
Zone 1 Circulator Zone 2
8J48A
829A
Relay 829A Relay
Figure 9. 8J48A - Millivolt Systems Zoned with Circulators
Thermostat
Zone 2
B1
To 750 MV
Thermopile
B2 B3 L1 L2
C1
BZTP
TWTV
C2
36C Series
Gas Valve
Factory-
Installed
Jumper
Field-
Installed
Jumper
PG TH-PG TH
Field-
Installed
Jumper
Thermostat
Zone 1
531
246
Thermostat
Zone 3
531
24
120 V
6
Circulator
Zone 3 Neutral
Hot
Line Voltage
Low Voltage