White Rodgers 8J48A User's Manual
Contents
1. ER 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 PART NO 37 4013C Replaces 37 4013B 9522 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 Ifa 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 t2. WHITE RODGERS 8J48A Relay Hot Water Control For use with 24 VAC or Self Generating Gas Valve Suitable for External Zone Valve Load INSTALLATION INSTRUCTIONS 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 atankless domestic coil by the addition of aseparate 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 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 an
3. d 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 E WHITE RODGERS DIVISION EMERSON ELECTRIC CO 9797 REAVIS ROAD ST LOUIS MISSOURI 63123 5398 Printed in U S A DESCRIPTION PRECAUTIONS To prevent electrical shock and or equipment damage disconnect electric power to system at main fuse or circuit breaker box until installation is complete A 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 dam age 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 WAT
4. k Conductive Grease No 145 0163 Figure 2 Stop Adjust Screw Pointer Figure 3 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 Transformer No 2 Relay Contacts Contacts pot Low Volt lt ow Voltage 36C L 120 VAC lt gt Room Thermostat Gas Valve lt x Neutral INTERNAL WIRING I I Line Voltage l Low Voltage I Circulator EXTERNAL WIRING Ie Motor Line Voltage Low Voltage AUTO MANUAL SWITCH For manual operation of self generating millivolt systems only The manual
5. per Line Voltage Low Voltage 36C Series Gas Valve TR TH TR TH Figure 8 8J48A 24 Volt Systems Zoned with Circulators Thermostat Thermostat Thermostat Zone 1 Zone 2 Zone 3 Line Voltage Low Voltage To 750 MV Neutral Thermopile 120 V 36C Series Gas Valve PG TH PG TH Figure 9 8J48A Millivolt Systems Zoned with Circulators
6. 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 Factory Field Manual installed installed Switch Jumper Jumper e ae IN A a ey No 1 Relay TH _TH TR_ TR Figure 4 24 Volt AC Gas Valve Factory installed Jumper yey al Transformer No 2 Relay Contacts I INTERNAL WIRING I Line Voltage I I I Low Voltage Circulator EXTERNAL WIRING Motor Line Voltage Low Voltage Low Voltage Room Thermostat Manual Switch No 1 Relay Contacts To 750 MV 30G 4 Thermopile Gas Valvg H TH TH PG PG Figure 5 Millivolt Gas Valve WIRING AND OPERATION cont d Thermostat ST TOY fromm ow Limi 6 E p ontrol Ww Ww NOTE Remove external jumper between W and Z terminals Circulator Motor Figure 7 Alternate Connections for using Separate Low Limit Circulator Control on Boiler with Tankless Domestic Coil 24V Hot Neutral Gas LINE Valve Figure 6 Typical Connections for Zoning with 2 Wire Zone Valves Thermostat Thermostat Thermostat Zone 1 Zone 2 Zone 3 Factory Installed Jum
7. ubing so that it cannot touch electrical components 8 Fitthe back of the case into the well and tighten using the set screw on the back panel 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 reposi tion the stop to the desired setting Retighten the stop adjust screw A WARNING DO NOT set the stop higher than the original manufacturer s recommended setting Personal injury and or property damage may result Slot Capillary Tube Well i 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 AZ _ H Well No Description A B 12 Std Shank 12 Std Ext Shank 3 4 Std Shank 3 4 Std Ext Shank 3 4 Extra Ext Shan
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