Thermostat for natural gas shop furnace

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Mar 9, 2012
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Our shop has a 100,000 btu natural gas shop heater we are having it hooked back up but it needs a thermostat. It appears to be a 2 wire thermostat. Any suggestions on what style or type to use?
 
Need more details . Is it controlled through a relay ? What is the supply voltage for the thermostat circuit ?
 
Do you ever need to set it below "normal" levels? There are low-temp/"garage" thermostats designed to be set at set points lower than normal thermostats can handle (think 30s-50s). If not, I'd go with a cheap Honeywell programmable.
 
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Do you need to set it below normal levels? There are low-temp/"garage" thermostats designed to be set at set points lower than normal thermostats can handle (think 30s-50s). If not, I'd go with a cheap Honeywell programmable.

Forced air furnaces like what you'd use in a house typically have a minimum return air temperature of 55F. A natural gas shop heater may have a similar requirement. Unknown what happens if you ignore this requirement, but I suspect it might be bad for the heat exchanger.
 
Why was furnace disconnected? Is combustion chamber compromised?
Look at proper draft through the flue.
Think safety with fossil burning appliances. Suggest furnace combustion analysis and a carbon monoxide detector.
 
Just gave two programmable thermostats to Goodwill as nobody wanted them on FB marketplace.

Depends on how you use it and what you are willing to spend.
If you want the ability to remotely pre-heat the shop, get something like a Nest or similar if two wires are enough for that.
Otherwise, probably just whatever is on-sale at the hardware or big box store.
 
I have a WiFi programmable on my garage heater...had to run new wire from the board to give it the 24V power in addition to the existing 2 wires but if you want to go that route your board should have a terminal. As others noted min temp is something to think about...my thermostat bottoms out at 50F which is fine with me and pretty much where I want it. I'll occasionally crank it up to 60 or 70 if I'm out there doing a project.

I can remotely raise temp, schedules as needed, low/high temp alerts to my phone, etc. which is why I replaced the old mercury round dial that was there when I moved in.
 
Manufacturers just don't list the low temp operating settings for grins. Low temps create condensation on burners, heat exchanger and flue. Condensate turns to acid. Fan can also short cycle till space gets up to temp. Just shortens the life of the unit.
 
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