Thermostat Suggestions Please

[dustyashell]

Hello all.

Looking for some suggestions.

... but first the facts: the garage in question is in Edmonton Alberta Canada (cold AF); detached fully insulated (door, walls, roof) double car garage; 240v Ouellet OAE Thunderstorm unit heater (which has a built in thermostat).

I am looking to install a better thermostat to replace the existing built-in one in order to improve efficiency.

Ideally I am looking for a smart thermostat on the 240v line, that operates down to 0° C (35° F). The idea being to keep the garage just above freezing until immediately before use when I would increase the temperature via wifi app or controller in the house.

Dimplex has a good solution:

https://www.dimplex.com/en/electric...trols/products/cst240/connex_smart_thermostat

and

https://www.dimplex.com/en/dimplex_...x_sup_r_sup_multizone_programmable_controller

This system meets one of the goals - It's programmable and and controllable from 50' away (in the house) (there is also a more expensive wifi model). Unfortunately, it's operating threshold, like most thermostats, is 40° F on the low end. Which means that I'd be wasting energy on five degrees unnecessarily.

The only low temperature thermostat I have seen is

https://www.honeywellstore.com/stor...eraturegarage-non-programmable-thermostat.htm

which is not compatible with high voltage systems... and does not fit the bill in any other way.

If there is something I've missed in my research please tell me. TL;DR looking for smart(wifi) and/or programmable low temperature (0° C / 35° F) thermostat for a 240v system - can't find what I'm looking for. Any suggestions are welcome.

Thanks a lot.

 

[Ohmthis]

How about adding a contactor controlled by a 24v tstat of your choice.

 

[peter2772000]

How about adding a contactor controlled by a 24v tstat of your choice.

This!

A 2-pole 24v 30A contactor goes for around $50 CAN retail. That and a 20-30VA 240/24v transformer and you now have a world of stats to choose from.

 

[dustyashell]

I'm sorry; I'm no electrician - could you walk me through how I would do this in a little more detail.

Thanks

 

[peter2772000]

Been trying to download a diagram I made this am thru google pics. I miss the ease that was Photobucket.....sniff sniff

https://photos.app.goo.gl/6Bi4ovrufMdRo5KI3

 

[dustyashell]

Wow. Thanks a lot Peter. That's awesome.

 

[dustyashell]

Anyone have any suggestion of a programmable or smart thermostat that goes below 40°F? Trying to get one down to 0°C.

 

[peter2772000]

Don't forget, the "heater 240" connections are the 24v connections to the contactor coil. You have to switch the actual 240 v to the heater thru the line/load terminals

 

[CoogarXR]

https://www.garagejournal.com/forum/showthread.php?t=372238

There's how I did mine, except I have mine controlling a window AC too.

 

[Stuff]

It is a 240v heater but you only need to switch one leg to control it. (For safety you need a separate switch to disconnect both legs when doing maintenance. Can be breaker within sight.)

You can use this combination transformer/relay to get 24vac terminals for a thermostat - https://www.amazon.com/dp/B0037MXM1C/?tag=atomicindus08-20 - It could mount on the side of the heater.

Note I see on Nest thermostats you can set a safety temperature of 35ºF. So when you turn the stat "off" it uses that as minimum temp. Others probably have the same feature but might go lower.

 

[bobbyjean]

ranco etc controls...models for most voltages and configurations...priced competitvley....is that spelled rite

 

[peter2772000]

ranco etc controls...models for most voltages and configurations...priced competitvley....is that spelled rite

Good point. We use Johnson Controls digital stats for walk-in coolers and freezers. They have quite a large temp range and open or close on temperature rise.

https://be-ebusiness.eu.johnsoncont...4A6AA02F31949672CA5290CB70F6078D666F17F159B80

Funny, we use these all the time and yet I didn't even think about it as an option