overhead gas heater

[halla]

I have an old humprey heater in my lightly insulated garage without a thermostat? It does have an internal shut off if it gets to hot but I'd like to be able to control the gas and the fan seperately. The system is currently turned on & off with a regular wall switch, but fan and gas either on or off. The fan has 2 wires and the unit has another 2 , can't see where they go? gas switch I guess. Is there a specific thermostat I need to get to regulate as stated? Where would I get a 120v gas heater thermostat. I've seen 120v for electric base board heaters but they don't have fans? TIA M Halla

[Wgoodrich]

I am not sure the term Humphrey heater. If this heater has a 120 volt power source that will shut off the gas valve but allow the pilot light to remain lit then you should be able to install a thermostat.

Problem is if the unit has a fan does that unit have a thermostat on the heater that will allow the gas to be shut off yet the fan still run till the unit cools off? This is a key concern. If your unit looses power and the gas shuts off same time the fan shuts off then that heater will continue to heat up even with the gas shut off raising the temp inside that heater substantially before it starts cooling back down.

Look to see if this heater has a built in fan switch, if it does then I would install a portable thermostat much like the ones used on torpedo heaters that shuts off only the main gas valve allowing the fan and pilot to continue to run.

To do that all you have to do is cut the black wire going to the gas valve that controls the cycling flame. Then install a hand held thermostat such as the ones used for torpedo heaters.

I am reluctant to tell you that you could use a baseboard heater wall mounted thermostat in place of your wall switch until we confirm you have addressed the fan continuing to run and cool down the heating unit after the flame shuts down.

Is there a safety thermocouple on the pilot light that will shut down this main gas valve if the pilot light blows out or is this a manually operated design heater only?

Hope this helps

Wg

[halla]

The unit was made by Chicago Gas Light Co. the model is called the Humphrey. The auto shut off only turns the gas off, the fan continues to run. It does have a pilot thermocouple to monitor the pilot. Im not fimiliar with the torpedo thermostat you referred to? Do you know of a device to shut the gas off and auto delay the fan shut off? That would be ideal. this is a large unit 70,000 btu, the only wires I can ID are the 2 to the fan motor. Looks like one goes to the gas valve and the other is somewhere higher in the unit, which is probably the auto shut off. Thanks for your help.

[Wgoodrich]

You said the auto shut off only turns off the gas. Does this auto shut off turn off gas to both the main burner and the pilot light or only turn off the main burner? Is this auto shut off electrically operated with two wires or mechanically shutoff without electrical connections? We have a problem with what a certain heater is being called in different regions of the Nation I suspect.

Is this heater portable or permentantly installed?

In your original post you are saying that gas and fan will shut off by the wall switch. This is not a good thing to cycle your heat safely and effeciently. You should find two wires going to your main gas burner valve. All you need to do is cut one of the two wires going to that main burner gas valve. If the pilot continues to run then place a normal baseboard heater thermostat between those to cut wires with no external power to that thermostat. Leave you wall switch as is. You can use a rubber cord 16 awg not more than 10 feet long to route that cut wire through that rubber cord to your baseboard thermostat installed in a floating weather proof junction box. This will do as you desire and allow portability of the unit if you so desire. This is the same design used on a torpedo heater that is on wheels. Then you can just hang the thermostat portable unit on a nail on a nearby wall to control comfort zone of your garage.

Just make sure the pilot light does not go out when you cut that one wire going to the main burner valve of your heater.

Hope this helps

Wg

[halla]

The unit is perminantly installed vented thru the roof. The auto shut off only turns main burner off pilot remains and main burner auto starts when unit cooled due to fan continueing. The wal switch does not operate pilot, stays on all the time, controlled via thermocouple. Will need to view where the other 2 wires go, not sure which one will further cycle burner without affecting auto safty shut off? Will look at the base board thermostats today and see if one wire an option?

[Wgoodrich]

If you gas valve is mechanically operated by thermocouple then you may have to break the wire to the high limit thermostat if electrically operated. There you can also tap and route power to the wall thermostat. Baseboard heater themostats come in double pole or single pole you would need the single pole routing power to the wire that will shut the valve through the thermostat then back to the other half of the wire you cut. This routes power to your valve through the thermostat for cycling on and off ability.

Let us know what you find

Good Luck

Wg