Historical furnace or heater question.


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 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 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.
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conversion burners installed in the 1950s had thermocouple protection. but I dont know how early it started, except I checked out a really ancient water heater from the 20s, that had no thermocouple
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On Thu, 10 Dec 2009 16:17:34 -0800 (PST), " snipped-for-privacy@aol.com"

Some had flame sensors instead of thermocouples. (CaDS - cadmium disulphide) photocells.
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Homes that have swimming pools may have a very serious danger when it comes to spontaneous combustion. Powedered swimming pool chlorine mixed with oily rags is a deadly combination.
Jimmie
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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 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 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.
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I think RBM hit the nail on the head. I have seen floor furnaces that were not thermostatically controlled that didn't have any safety, but they work about like a top burner on a gas stove, or a gas space heater. You just turn the valve on and off, and adjust the size of the fire to the amount of heat wanted. These furnaces were also antiques when I saw them about 35 years ago. Some thermostatically controlled units had mechanical safeties that worked with a bimetal that bowed when heated by the pilot and opened a valve built into the burner to let gas through, and closed it when the pilot was out. They were not 100% to begin with-- they did not stop the gas to the pilot-- but the valve would often stick open, or partially oped, so they were not very safe at all. Larry
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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 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 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
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the gas company will likely inspect the entire house and could red tag it shutting off all gas and heat:(
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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 donít have a concern about the safety. I know itís unsafe. I simply wanted to know if thatís 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 thatís 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 donít have a concern about the safety. I know itís unsafe. I simply wanted to know if thatís 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 thatís all they knew.
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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 donít have a concern about the safety. I know itís unsafe. I simply wanted to know if thatís 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 thatís 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 donít have a concern about the safety. I know itís unsafe. I simply wanted to know if thatís 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 thatís all they knew.
How is the main gas burner turned on and off?
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RBM wrote:

...
I'm quite sure it was. I have a heater of roughly that vintage operates same way. It was in the bathroom of the house in which I grew up which was moved from the location for the AAF base built during WW II as a B-24 training base. That was '42; whether the heater was in the house when it was moved or was added at the time of the move I don't know but it provides an indicator of when such was still in practice. BTW, the heater is still in use in the well house for freeze protection...never been an issue in some 60+ years so it's one of those "could be, but practically doesn't seem to be" much of an issue.
Actually, as I write this and thinking -- I've never had the thing apart enough to figure out where it is, but somewhere even in this there is a control--when the pilot is out, the main doesn't come on even though there is buildup from the pilot. It has never accumulated enough to have been an issue, however.
...

Like the above heater, undoubtedly w/ a wrench at the disconnect valve.
The burner itself, as noted above, does have a control and it's clear it has to or the burner flame would have to be on continuously. I'm presuming there must be a bimetallic strip in Mollie's as well just as there must be in this guy, too; I just am not positive where it is now. Come spring when I turn it off maybe I'll explore some if this topic hasn't been totally forgotten by then... :)
--
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