"Molly Brown" wrote in message
...
On Dec 11, 2:21 am, "Roger Shoaf" wrote:
"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.

Molly,

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
unit.

Hope this helps.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube,
then
they come up with this striped stuff.

No red button. Just a lever to turn the gas on or off to the pilot. No
thermocouple. The gas to the pilot is either on or off and is
controlled by the lever. No I don’t have a concern about the safety. I
know it’s unsafe. I simply wanted to know if that’s how it was when it
was first designed before 1949. It was unsafe to have cast iron steam
engines but people used them anyway just because that’s all they
knew.

No red button. Just a lever to turn the gas on or off to the pilot. No
thermocouple. The gas to the pilot is either on or off and is
controlled by the lever. No I don’t have a concern about the safety. I
know it’s unsafe. I simply wanted to know if that’s how it was when it
was first designed before 1949. It was unsafe to have cast iron steam
engines but people used them anyway just because that’s all they knew.

How is the main gas burner turned on and off?