Use Honeywell thermostat to control 2 different heaters

DrewE wrote:
The cadet heater has a built-in thermostat. How accurate it would be is, of course, pretty questionable; but before dabbling with too much wiring and switches and stuff, why not see if it is sufficient to just use its built-in one?

From the info on their web site, the built-in thermostat is simply wired to switch the main leads and the fan motor and heater element operate simultaneously (i.e. there's no thermostatic switch for the fan or other means of making it operate after the element is switched off). Switching the power to the unit with an external thermostat would make it operate in exactly the same way and would not cause any problems with the unit.

You already have it and it has a built-in stat.... They do work - sort of. A thermostat right on a heater can't sense what the rest of the room is doing and you will likely find it is cycling on and off more. It can't be set at a specific temp and you may find having to crank it up for a while until to find an acceptable comfort level rather than setting it at what you want and leaving it alone. The ideal thing is to have a more centrally located stat on an interior wall. You can always just disconnect it internally. Or it might make a good spot for a disconnect switch. Maybe just try it and see how well it works for you and if desirable, add a remote stat later.

Some wall/ceiling fan heaters (QMark, ex.) have a cool-down cycle to keep the fan running a bit after the thermostat tells the heater to shut down (requires an extra wire to the heater). Specifications for the Com-Pak shows just 2 wires to the internal stat. and you could just disconnect it without affecting the operation of it and add a remote stat. It looks like there is an "R" version of the heater for use with a remote stat which is essentially the same thing without the built-in feature.

MrWizard also has a good point. If you lose shore power, you can run the furnace independently. Another thing being separated is you could have the furnace adjusted to run at a lower setpoint so it supplements the electric heater to warm the interior space faster when you first get to a CG.

+1 to use the existing thermostat or switch and see what is really needed.
If it is that cold.... the 5112 electric BTU could run continuous and you would still set the temp by the furnace.

The cadet heater has a built-in thermostat. How accurate it would be is, of course, pretty questionable; but before dabbling with too much wiring and switches and stuff, why not see if it is sufficient to just use its built-in one?

From the info on their web site, the built-in thermostat is simply wired to switch the main leads and the fan motor and heater element operate simultaneously (i.e. there's no thermostatic switch for the fan or other means of making it operate after the element is switched off). Switching the power to the unit with an external thermostat would make it operate in exactly the same way and would not cause any problems with the unit.

Keep it separate.

I would use a low voltage thermostat because it's easier to run LV wiring around than romex. Use a low voltage stat like a White Rodgers heat only 1C20R (looks like a Suburban one). Use a small 120/24 volt transformer, 20VA. Use a heating relay like a Honeywell R841 with or without integral transf. You can get a heating relay that is instant off like an AUBE RC840 (not cheap tho.)

I would suggest installing a line voltage switch so you can turn the power off when not there, parked at home or you want to plug in a heavy load. The Honeywell R841 takes a minute or longer to turn off the heating load when the call for heat is removed. Also, a low voltage stat. has a heat anticipator that delays the off - you can turn it to the lowest setting but it won't be instant off.

You could also install a line voltage stat. with an off indication if you can get the wiring to the stat. location.

Not sure where your heater will go and where the existing t'stat is, but if you put a new LV stat beside the existing, there's very likely a hole in the top plate of the wall that you can fish a new wire through. I've done that a few times now.

Rather than using that Cadet heater, can I suggest another one? Look at the King PAW "pic-a-watt" series heater King PAW specs.. You can set the wattage in 250 watt increments from 250 to 1500 watts. Also, because it has a tangential blower, it is super quiet. I am installing this one in our TT. It's so quiet, you have to put an ear up to it to check that it is on. I think you will find that the Cadet heater (or similar ones) will be rather noisy because it has a propeller type fan. I installed a similar one in our first TT and it was really noisy and I'd never use another one like again in a TT. Most wall heaters have a propeller fan.

Assuming that you have the correct clearances from wall and other surfaces, one thing you may want to think about is what happens when head back home. If you plug in at home, is there enough clearance when slide(s) is in and what if you unintentionally leave the heater running? You could install a relay to latch the power on and will only re-energize the power by hitting a momentary contact switch - easy to do. I'm using a Finder #66.82.8.120.0000 relay to do this. Finder power relay

Did that, works great.

Use 115 when available, propane when dry camping.

Doug

You can try it...But I don't like the idea

I would prefer separate stats for each heater
Set the wall electric heater at one temp
And the L.P. furnace at another lower temp
If the wall electric isn't enough and can't keep up the furnace will come on
If shore power fails and no electric the furnace well come on

Your way you wake up cold and have to go switch the stat