White Rodgers 37C73U User Manual
WARNING
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WARNING
!
WHITE-RODGERS
37C73U
Water Heater Thermostat Control
Installation Instructions
FOR NATURAL GAS ONLY
RETAIN INSTRUCTIONS FOR FUTURE REFERENCE.
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HOTTER WATER
INCREASES WITH
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CAUTION:
Fixed Adjustment Main and Pilot Regulators
The main and pilot gas regulators require no field
service. They automatically control and maintain the
outlet main and pilot burner gas pressure.
FOR YOUR SAFETY
“WHAT TO DO IF YOU SMELL GAS”
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire
department.
Do not use this Natural Gas control on a LP Gas
water heater. Improper operation could occur, resulting in personal injury and/or death due to Carbon Monoxide poisoning, fire, or explosion. Check
for proper gas type as listed on the rating plate
affixed to the water heater.
FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS BEFORE INSTALLING OR OPERATING THIS
CONTROL COULD CAUSE PROPERTY DAMAGE, PERSONAL INJURY AND/OR DEATH.
1. This control must be installed or serviced only by a
professional.
2. Do not use force when moving the gas control knob. If
you cannot turn the knob with hand pressure only, the
control must be replaced.
3. Do not use the control if the knob will not “pop up” after
being depressed while the knob is in the PILOT posi-
6. In some situations, the gas may lose its odor. To detect
unodorized gas, you must have a gas detector which
can be purchased from your gas company. If you do not
have a detector and have the slightest suspicion that
gas may be present, get out of the house and call the
gas company. DO NOT RELY TOTALLY ON YOUR
NOSE.
tion. The mechanism is damaged and the control must
be replaced. Shut off gas to the water heater.
4. For your safety, this control is supplied with tamper
resistant screws. Do not attempt to repair or adjust the
control. If you experience problems, replace the control
immediately. Continuing to use a damaged control
could result in fire and/or explosion.
Scald burns occur in under one second with 160°
water, which this thermostat will deliver if the
temperature dial is set at “VERY HOT”. Lower
settings of the temperature dial will reduce the risk
of scald and will reduce your fuel bill.
5. An odorant has been added to the gas to help you
detect it. Before lighting, search for the odor of gas by
sniffing at floor level around the water heater.
WHITE-RODGERS DIVISION
EMERSON ELECTRIC CO.
9797 REAVIS ROAD
ST. LOUIS, MISSOURI 63123-5398
Printed in U.S.A.
PART NO. 37-6092A
9912
INSTALLATION
CAUTION
!
REPLACEMENT INFORMATION
REMOVING OLD CONTROL
1. Shut off gas to water heater.
2. Shut off water at cold water inlet.
3. Connect hose to heater drain cock. Drain water to a
nearby drain. Open a hot water faucet for faster draining.
4. Disconnect gas line at union (figure 1). Remove piping
from old control.
5. Disconnect the:
a. Thermocouple (left side).
b. Pilot burner (small tube on the right side)
c. Main burner (large tube in the middle).
6. Remove the control by turning it counterclockwise
( ). If needed, a short piece of 1/2” black iron pipe
can be screwed into the control inlet to increase leverage.
SPECIAL INSTALLATION NOTE
If replacing a Unitrol or Robertshaw control, install extension adaptor fitting provided into the outlet of the control.
If replacing a control with 3/8" NPT outlet, install small
adaptor fitting provided into the outlet of the control.
Gas supply
pipe
Gas shut-off
valve
Union
(metal-to-metal)
Tee
Drip leg
(sediment trap)
Pipe cap
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To main burner
To thermocouple
Figure 1. Typical gas connection
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HOTTER WATER
INCREASES WITH
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RISK OF SCALDING
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To pilot
burner
INSTALLING NEW CONTROL
All piping must comply with local and state ordinances or
with the National Fuel Gas Code (ANSI Z223.1–NFPA 54),
whichever applies.
Dirt or contamination in the gas line can block the control
from operating creating a risk of explosion, injury or death.
To protect the control from dirt/contamination, a drip leg or
sediment trap (see Figure 1) must be installed in the piping
leading to the control.
1. Apply pipe joint compound to the male threads of
control, leaving the first two or three threads clean.
2. Install control in tank. Turn clockwise ( ). Use a
short piece of pipe to help in turning. Align the control so
that burner and pilot tubes may be connected.
3. Make burner, pilot, and thermocouple connections. Do
not use pipe joint compound or teflon tape. Thermocouple nut should be hand tightened and then turned an
additional 1/4 turn with a small wrench. DO NOT OVERTIGHTEN.
4. Connect gas line. Use new black iron pipe that has been
properly reamed. If old pipe is used, be sure it is clean
and free from rust and scale. Use pipe joint compound
on male threads only. (Use a pipe joint compound
approved for natural gas service.) Do not use TEFLON
tape. Do not apply compound to first two threads.
5. DO NOT use joint compound or tape on the union
connection.
6. To fill the water heater with water:
a. Close the water heater drain valve by turning the
handle to the right (clockwise). The drain valve is on
the lower front of the water heater.
b. Open the cold water supply valve to the water
heater.
NOTE
The cold water supply valve must be left open
when the water heater is in use.
c. To ensure complete filling of the tank, let air exit by
opening the nearest hot water faucet. Allow water to
run until a constant flow is obtained. This will let air
out of the water heater and the piping.
d. Check all new water piping for leaks. Repair as
needed.
Never use this water heater unless it is completely
filled with water. To prevent damage to the tank,
the tank must be filled with water. Water must flow
from the hot water faucet before turning ON gas to
the water heater.
7. Open gas shutoff valve.
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