Simple thermostat for shop heater?
#11
Question    
I have a 7000W, 220V wall-mounted electric heater I will install in my garage soon.  It's designed to be hardwired with a thermostat controlling it.  I went to the local borg stores and only found thermostats similar to those that are used in a house.

I need a relatively simple thermostat.  It needs to have on/off capabilities and the ability to set the temperature to around 50*F or so for heating when it's really cold.  Can you guys recommend something for me?
Semper fi,
Brad

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#12
  Re: Simple thermostat for shop heater? by ®smpr_fi_mac® (I have a 7000W, 220V...)
A friend of mine put one together with a normal house thermostat and a relay large enough to handle the load. The furnace thermostat triggered the relay, turning on the heat. I have been planning on doing the same but never got around to it. I've gotten pretty good as swinging the knob on my heater to get about the right heat.

The heater may have a contactor in it which may act as the relay... then you can control the heater with a low voltage line.
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#13
  Re: Simple thermostat for shop heater? by ®smpr_fi_mac® (I have a 7000W, 220V...)
We have a thermostat something like THIS.  Very basic, and it has worked for years out in the shop.  It may not have on/off.

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#14
  Re: Simple thermostat for shop heater? by ®smpr_fi_mac® (I have a 7000W, 220V...)
You're saying you need a thermostat with a capacity of about 40 amps with 240v? 

A better way is with a 40 amp contactor with a 24v coil, 24v secondary/240v primary transformer, then choose any heating thermostat that operates on 24v. Any electronic Tstat today will operate heat only. Use a #18 3 wire (use a common on some). There are a few that will not go down to 50* though.
"There are no strangers- only friends I haven't met.
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#15
  Re: Simple thermostat for shop heater? by ®smpr_fi_mac® (I have a 7000W, 220V...)
Baseboard thermostats are usually available at the elec suppliers.
Steve





Working on 20,000 Winkgrin





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#16
  Re: Simple thermostat for shop heater? by ®smpr_fi_mac® (I have a 7000W, 220V...)
Maybe a line voltage t-stat?
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#17
  Re: Simple thermostat for shop heater? by ®smpr_fi_mac® (I have a 7000W, 220V...)
Does it need to be a line voltage thermostat? If not, you can get thermostats for garage and outbuilding use. I recently had to replace the one in my shop and found a Honeywell t-stat intended for the job. If you don't need a line voltage thermostat, I'll look up the model number.
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#18
  Re: Simple thermostat for shop heater? by ®smpr_fi_mac® (I have a 7000W, 220V...)
Both shop and house are using Honeywell thermostats.  It's what the installers brought when they set up a new system.

I have a thermostat in the shop that looks very much like this, though it doesn't ahve the emergency heat switch setting: Programmable thermostat 

As I was looking at their site, they had the old-school thermostat, which I think would be better for my basic shop application:  The old standby

There's tons of selections on the Honeywell site.  I really don't care about programmable anything for out in the shop; I'm not on a regular use cycle out there.  I adjust the thermostat every time I go out there.  Wish I had one of those old style units.

OBTW: Honeywell's site listed at least one line-voltage unit.
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#19
  Re: Simple thermostat for shop heater? by ®smpr_fi_mac® (I have a 7000W, 220V...)
My apologies, gents. I thought it required an external thermostat, but it has one built in. It can't be set to a specific temperature, though. You turn it turn it all the way on then rotate the thermostat down until it shuts off, then turn it back just until it turns on to maintain that temperature.

This will be inconvenient, at best, because it's supposed to be mounted 8' off the floor, which I'll do, because I have 12' ceilings and will be mounting cabinets.

The manual includes instructions for bypassing the internal thermostat for an external. I think that some Honeywell unit listed by Ron will work.

daddo, yes, it is a 40A unit. I'll need to get the appropriate breaker and 8AWG cable for it. I'll also put an inline switch on the wall because the heater will be high up on the wall.

Much of what you guys are talking about is Greek to me. I understand the basics of electrical theory and can install basic circuits, but don't know much of the terminology.
Semper fi,
Brad

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#20
  Re: RE: Simple thermostat for shop heater? by ®smpr_fi_mac® (My apologies, gents....)
Does it have a schematic with it ?  If it does can you post it.    It may have a internal relay that will allow you to use just a thermostat.    Roly
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