Specifications

TM016 Rheem Gas Permanent Pilot Service Instructions
D.O.I: 01/2006
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Magnetic Valve
A solenoid type gas isolating valve held in the open position by a small electric current
generated by the thermocouple. This valve will completely isolate the supply of gas to the
burner and pilot in the event of a pilot flame failure.
Thermal Switch
A one-shot safety device mounted in the thermocouple near the gas control that senses
excessive heat outside the combustion chamber. This device cannot be reset and must
not be bypassed.
Thermocouple
A device that generates a small electric current when heated. Thermocouples are
available in TS (thermal switch) and Non-TS types. The current generated by the
thermocouple is used to hold a magnetic valve, fitted in the gas control, open.
The pilot assembly is designed to ensure that a Non-TS thermocouple cannot be
substituted in place of a TS thermocouple during replacement.
The use of a TS thermocouple is to provide a safety shutdown in the event of a blockage
in the combustion chamber or flue.
IMPORTANT: If replacing an open circuit TS thermocouple it is essential to
investigate the cause of failure. Possible causes include: incorrect installation of the
water heater i.e. incorrect distance from corners or walls; reverse fluing; exhaust fans or
air conditioners near by etc.
The original TS thermocouple had the thermal fuse mounted externally on the outer sheath
of the thermocouple (see diagram below), the current style of TS thermocouple has the
thermal fuse integrated inside the outer sheath. A nickel coloured nut at the gas control
end of the thermocouple identifies this type of TS thermocouple. Non-TS thermocouples
have a brass coloured nut.
Original TS thermocouple
Current TS thermocouple