Can anyone give me any information on when a fail safe circuit using a
thermocouple or pilot generator for a heater became standard for
household use or when it became mandatory for manufacturers of
I have an Adrews floor heater. Yes itís VERY old. It doesnít seem to
have a fail safe circuit. I am very curious as the whether it never
had it or if someone messed with it.
Yes I know all about pushing in and holding down the pilot control rod
to light the pilot but this rod isnít going down or up, it only
Yes I know I should replace the entire heater and I am in the process
of replacing it now or very soon. I am simply curious about its
operation that is all. Any historic information you can give would be
greatly appreciated. Thank you.
Since you have the red button you need to push to light the pilot, you do
have a gas safety valve. The red button allows gas to flow to the pilot
light until the pilot light heats up a thermocouple. The thermocouple
creates a small amount of electricity when heated and that holds the safety
valve open allowing gas to flow to the main burner. If the pilot light were
to be extinguished, the power flowing to the coil in the safety valve would
shut off all the gas.
If you have concerns about the safety of the furnace, you gas company will
usually perform a free safety check. The biggest concern with something
that old is a cracked heat exchanger. If the heat exchanger is cracked the
flue gasses could enter your home instead of going up the flue pipe.
The old unit is also a lot less efficient than a modern furnace, so you are
burning more gas than you would to get the same heat with a more efficient
Hope this helps.
About the time I had mastered getting the toothpaste back in the tube, then
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