"Molly Brown" wrote in message
...

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
furnaces.


I have an Adrews floor heater. Yes it’s VERY old. It doesn’t 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 isn’t going down or up, it only
turns.
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.

My belief is that any gas heating unit with an electromechanical solenoid
valve that opens and closes the main gas valve, and being controlled by some
type of temperature sensor, would have to have some mechanism to assure
flame.