White Rodgers 37-5488A 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 into a single
enclosure: a high limit control, low limit-circulator control,
circulator relay, transformer, together with terminals for
wiring. They are for use on boilers equipped with tankless
domestic coil.

Although these controls are designed for use with a line
voltage gas valve or oil burner control, they may also be
used with low voltage primary controls.

The internal transformer supplies power for operating the
relay coil and systems zoned with motorized water valves.

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.

TYPE 8B43A-601

RELA Y -HOT W A TER CONTROL

For Use With Line Voltage Primary Control

(Suitable for External Zone Valve Load)

INSTALLATION INSTRUCTIONS

DESCRIPTION

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
voltages. Higher voltages will damage control
and could cause shock or fire hazard.

ELECTRICAL DATA
Input Voltage: 120V.A.C., 60Hz
Circulator Motor: 120V.A.C. 8F.L.A. 48L.R.A.
Burner Circuit: 120V.A.C. 8F.L.A. 48L.R.A.

Ignition Trans.: 3.0 Amps
Burner Motor: 7F.L.A. 42L.R.A. or 125 VA Pilot Duty

Motorized Valve: 1.2A. Max.
Room Thermostat:

Set adjustable heat anticipator at 0.25 Amps. For fixed
anticipation thermostats, use 0.20 to 0.30 Amp. heater.

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.

WHITE-RODGERS DIVISION

EMERSON ELECTRIC CO.
9797 REAVIS RD., ST. LOUIS, MO. 63123
[phone], FAX [phone]

9999 HWY. 48, MARKHAM, ONT. L3P 3J3
[phone], FAX [phone]

R

Printed in U.S.A.

SPECIFICA TIONS

THERMAL DATA
Range: High Limit - 140° to 240°F (60° to 116°C)

Low Limit / Circ. - 100° to 200°F (38° to 94°C)

Differential: High Limit - 10°F Fixed (5.5°C)

Low Limit / Circ. - 10° to 35°F Adj. (5.5° to 19°C)

Switch Action: High Limit - Open on rise

Low Limit / Circ. - SPDT

Well: 1/2" or 3/4" Thread Size

INSTALLATION

Install control as follows:

1. Install well securely into proper tapping.

2. Remove control cover. Then loosen the two screws
holding well clamp to back of case. NOTE: Loosen
until ends of screws are flush with well clamp for
easiest assembly.

PART NO. 37-5488A

Replaces 37-2935-1

37-9333-1

9512

INSTALLATION CONT.

3. Insert sensing bulb into well, forming capillary so bulb
bottoms in well. Raise control onto well, slipping
flange on well between back of case and well clamp.
Be sure well fits snugly into hole in case. Then tighten
well clamp screws evenly and securely.

CAUTION

Do not dent or bend the bulb of the temperature
sensitive element as this will prevent it from fitting
properly into the well.

For best control performance it is recommended that
the existing well be replaced with a well shown on
page 3. However, by using the heat conductive grease

supplied in tube, these controls will give satisfactory
performance when used with larger-diameter existing
wells of many controls.

Use of adaptor requires that the existing immersion well
be equipped with a set screw. After removing old control,
install new one as follows:

DIAL SETTING

When replacing an existing control, adjust settings to
correspond with those of the old control.

Setting the High Limit

Set pointer to temperature at which contacts are to open.

Setting the Low Limit-Circulator

1. Set brass pointer to lowest temperature of cycle.

2. Set aluminum pointer to highest temperature of cycle.

NOTE

Always set the high limit 20° or more above the low
limit.

WIRING AND OPERATION

All wiring should be done in accordance with local and national electrical codes and ordinances.

The diagram below shows wiring connections for a typical
oil-fired installation. Operation is as follows:

When the room thermostat is not calling for heat, the low
limit-circulator control operates the burner motor as
necessary to maintain the domestic hot water supply at
the desired temperature (burner “on” when R-B contacts
are closed).

When the room thermostat closes its contacts, the relay
coil is energized and closes its two sets of relay contacts.
The burner starts as the No. 1 Relay Contacts close. If the
R-W contacts of the low limit-circulator control are closed,
the circulator motor also starts as the No. 2 Relay
Contacts close. If the R-W contacts open while the
thermostat is calling for heat, the circulator motor stops
but the burner stays on.

When the room thermostat is satisfied, the circulator
motor stops as the No. 2 Relay Contacts open. The
burner motor also stops as the No. 1 Relay Contacts
open, unless the R-B contacts of the low limit-circulator
are closed.

WELL
CLAMP

ADAPTOR
FLANGE

Fig. 1
MOUNTING TO EXISTING WELL
(for types with well adaptor)

1.

Remove cover and loosen two screws holding well clamp.

CONTROL CASE

WELL ADAPTOR
(F71-0924)

CAPILLARY

BULB

2. Fit capillary into slot in adaptor and push adaptor
snugly into opening in back of case so adaptor flange
fits between well clamp and case. Then tighten well
clamp screws evenly and securely.

3. Apply heat conductive grease (supplied in tube) to fill
void between bulb and well.

4. Insert bulb into existing well, forming capillary so bulb
contacts bottom and side of well. Attach control to well by
tightening set screw securely. (Be sure set screw is not
directly above slot in well adaptor before tightening.)

POINTER

HIGH LIMIT LO LIMIT - CIR.
180

140160

240220200

SET HIGH LIMIT 20° OR MORE

ABOVE LOW LIMIT

Fig. 2

200 180

160

100 120 140

BRASS
POINTER

If boiler temperature exceeds the setting of the high limit,
the burner motor stops. If thermostat is calling for heat,
the circulator continues to run.

EXTERNAL WIRING

Line Voltage
Low Voltage

HOT

1

LINE

2

N

Fig. 3

INTERNAL WIRING

LOW LIMIT-CIRC.
CONTROL

B

R

W

#2 RELAY
CONTACT

C1

C2

ZC

ZC

Line Voltage
Low Voltage

#1 RELAY
CONTACT

S1

S2

B1

B2

CIRCULATOR

TRANSFORMER

HIGH
LIMIT

MOTOR

LOW VOLTAGE
THERMOSTAT

T2

T1

Z

TYPE 668 OIL

BURNER CONTROL

(LINE VOLTAGE)

2

ALUMINUM
POINTER

RELAY
COIL

IGNITION

TRANS.

BURNER

MOTOR