emergency off switch

[Motown 454]

Hi Guys I finally got my heat up in my garage, it a Haet Star 45,000 btu Natural gas. I put an emergency switch before the heater. My thermostat only goes down to 45* the temp in the garage has already gone below that and the heat came on in the middle of the night. I've been using the Emergency off switch to keep it from coming on. Will that damage anything? I make sure the heater is off and cool before I turn it off.

 

[smalltown]

Motown I have a Sterling heater, and there is a section in the owners manual on minimum heat. Not sure if it's applicable to yours.

"Unit heaters should not be installed to maintain low temperatures and/or freeze protection of buildings. A minimum of 50°F (10°C) thermostat setting must be maintained. If unit heaters are operated to maintain lower than 50°F (10°C), hot flue gases are cooled inside the heat exchanger to a point where water vapor (a flue gas by-product) condenses onto the heat exchanger walls. The result is a mildly corrosive acid that prematurely corrodes the aluminized heat exchanger and can actually drip water down from the unit heater onto floor surface. Additional unit heaters should be installed if a minimum 50°F (10°C) thermostat setting cannot be maintained".

 

[Bondo]

I've been using the Emergency off switch to keep it from coming on. Will that damage anything?

Nope,.... Won't hurt a thing,...

 

[royalton10]

Somewhere I thought I read that Honeywell thermostats can be used for the lower temperatures desired. Not sure how low they go.

I have an electric heater that also has thermostat and kill switch as yours is. I make a habit of having kill switch off when heater is not being used.

Looks like a great shop and heater setup you have there.

 

[logical]

My Dayton 75k is tied to a Dayton thermostat made for greenhouse use, it can be set down to 30 degrees and supposedly is better for a somewhat harsh environment (like a garage). Take a look at one of the bigger online greenhouse supply sites.

That said, I generally set it around 45-50 minimum and crank it up when needed. I have a sink in the garage and have had issues before it was heated with car waxes and other stuff getting nasty if left to freeze. I kept it around 40 for many winters but lately have left it in that 45-50 range. I'm pretty well insulated and if I can break my wife of the habit of leaving the 18 Ft door open when she walks out to get the mail it doesn't run all that much unless it's below 25 degrees outside.

 

[JohnK007]

Don't see why it would hurt anything as long as you don't shut it down in the middle of a cycle. Matter of fact I should do the same thing as I have been known to leave the garage for the night and not turn down the thermostat. A shut off switch with a glowing red light by the man door to remind me it's on sounds like a good idea.

 

[myredracer]

You could use a low temperature thermostat like the Honeywell CT50K1028/E. It's specifically designed for shops and garages where you want to reasonably accurately control the temp. down to a few degrees above freezing. Have one in our "parking" garage to keep the two cars and contents somewhat above freezing and it works great. A regular 'stat just won't work well, if at all, at low temps.

If the heater has a cool down cycle, then the 'stat will make that work and you won't need to shut the power off all the time.

I assume the 'stat is mounted on an interior wall. They won't work that well on an exterior wall, esp. if not insulated.

 

[theoldwizard1]

By code, all furnaces MUST have an ON/OFF switch.

I have 2, because the guys installing my new AC could not find the original switch. Of course they wanted to know why the circuit was dead when they went to test it !

 

[Bondo]

By code, all furnaces MUST have an ON/OFF switch.

I have 2, because

Ayuh,.... Mine are oil boilers, not that it matters, I also use 2 emergency switches,....

One that's easy to get to quickly from the livin' space, as per most codes,...
'n another, right at the boiler,.....

That way, I can switch it Off, to service 'em, without goin' back up stairs,...

 

[Motown 454]

Thanks everyone.
I always let it shut itself off before I kill the power with the switch. That way it's already cooled off. I guess I'm good to go because I have a cold water supply but its on a hose bib that has the valve inside the cellar so it won't freeze. In fact you can see it in the second picture next to the gas pipe coming through the wall.

Thanks again.

 

[Ainsley]

Only damage you might do is if you don't let it do its cool down cycle. Ie the time between killing the flame and killing the blower fan.
You could use the on-off switch on the T-stat or use the switch to open and close the black wire coming from the T-stat.

 

[Charles (in GA)]

You could use a low temperature thermostat like the Honeywell CT50K1028/E. It's specifically designed for shops and garages where you want to reasonably accurately control the temp. down to a few degrees above freezing. Have one in our "parking" garage to keep the two cars and contents somewhat above freezing and it works great. A regular 'stat just won't work well, if at all, at low temps.

If the heater has a cool down cycle, then the 'stat will make that work and you won't need to shut the power off all the time.

I assume the 'stat is mounted on an interior wall. They won't work that well on an exterior wall, esp. if not insulated.

It works, thats about all I can say about this thermostat. The thermometer portion can be set to anything you want, so it isn't accurate at all. and the markings on the temp set are, well, just numbers on the front of it. If you set it, and keep tweaking it till you get an actual room temp you like (using a decent room thermometer), and then DON"T MESS WITH IT except to use the on/off switch, I suppose its OK, but I gave up and removed it. Finally bought an old school Honeywell mercury thermostat on Ebay and the back plate with the air/off/heat switch and that one I like. No air, but I do use the off/heat portion of it. It has a thermometer that actually points at markings and is reasonably accurate, and the set temp is the same way, pointer actually points at marks and numbers so you can accurately set it.

Only damage you might do is if you don't let it do its cool down cycle. Ie the time between killing the flame and killing the blower fan.
You could use the on-off switch on the T-stat or use the switch to open and close the black wire coming from the T-stat.

For the most part, that is the sensible thing to do, is leave the heater powered and use the on/off switch on the thermostat to shut it down, that way, if the fan wants to cycle two or three times before it is fully cooled down, you don't have to wait, just switch it off and leave.

Charles

 

[volaredon]

I saw something within this thread that brings up an interesting question. about thermostat mounting location.

I have a 30x36 garage that I have just hooked up a Modine unit heater within. I bought the same low temp Honeywell T stat shown a couple of posts above. Somewhere above it is said not to mount on outside wall. (mine are insulated) Problem being is that they are all outside walls! It's a garage, not a house with separate rooms. I have my heater mounted to the ceiling in the NW corner about 8' from the North wall and 3 feet from the west wall. Heater is pointed to blow diagonally toward the SE corner, my overhead doors (2 of them, 9X8) are on the south wall. Not yet operational as I still have to cut the hole in the roof for the flue pipe.

I had figured on putting the thermostat on the west wall behind the heater, between heater and the corner so that heated air would not be blasted onto the stat, where it would affect temps the heater would run. Mounting would be right next to my electrical subpanel.

I do have a 8' tall shelf unit along the north wall that sticks out 30" from that north wall, entirely "behind" the blast of heated air. this is a heavy industrial shelf unit that will not be moved any time soon, if it ever will be. The west edge of this shelf unit, is 10' from that NW corner.
Would it be better to mount the stat to this shelf unit, which would get it off the outside wall by 30"? There is a window on the north wall, basically right behind and next to this end of the shelf unit.

also; What I read above about not using a unit heater to maintain temps below 50*/// I understood that statement and its reasoning listed with it to not be a function of thermostat capability as the post-ers that contributed here between that post and mine, appear to have thought. my intent is (was) to maintain 40-45*F all the time and raise it to ~55 or 60 just when I am out there working. My stat is capable of going down to 35* just like the one posted. so will this "eat out" my heat exchanger?

 

[Motown 454]

I just wanted to update this, I picked up the thermostat Gil suggested and its in and working fine.
Thanks !