Replacing programmable thermostat for baseboard heating - compatability issue

red sox 2004

I have looking to replace an old thermostat in my finished basement with a programmable one. I have replaced several of these already in the upper level of my home which is heated via a boiler and hot water baseboards. Those were easy to replace, even for someone with my limited skill set.

When I removed the old thermostat in the basement, the two connecting wires (one white and one red) coming out of the wall were very thin and not compatible with the much thicker wires coming out of the back of the programable thermostat that I had purchased strictly for electic baseboard heating. I thought the wires coming out of the wall would be of the same thickness (gauge). Am I missing something here? Can I use the same type of programable thermostat I used elsewhere in my home? The gauge of the thermostat wire coming out of the wall looks the same as all the other ones in my home. I thought I need one specifically for electric baseboard heat?

Any help would be appreciated - thank you !

TarheelTerp

The smaller wires are likely to be LOW VOLTAGE control wires.
This is a GOOD thing if they lead to the relay that your heater load should then be running through. Good because this is what I was going to suggest you do before reading you already have LV control wiring in place.

If what I describe is the case (do some poking around to find the transformer and relay)... you can return the line voltage t-stat to the store and get a regular (24V probably) thermostat which will give you many more options in programming and for less cost too.

hth

red sox 2004

great - that's what I thought could be the case.

dumb question - how would I find the transformer and relay? the entire basement is sheetrocked. Is there a way to test for it? I'm pretty inept when it comes to electrical work.

thanks again

TarheelTerp

they'll probably be (should be) in a box near the panel.
If you're really inept... ask your handiest neighbor over to help.

hth

biggles

have somebody touch the wires on and off and go to the clicking sound....that's the relay the 2 wires are controlling make sure the new programmable might be looking for a 3rd wire as in the C side of the TR that controls that baseboard

red sox 2004

you lost me there - there's only a red and white wire hooked in to the current thermostat

anesthes

I didn't realize there was such a thing. I'd like to use low voltage thermostats to control 240v baseboards in each room as a temporary use to get me through the winter (and final inspection) of my new construction, so I could take my time on a hydronic boiler install in the summer.

Could you link me to these "relays" ? I need to control 3 zones.

-- Joe

TarheelTerp

Not gonna comment about your inspection window issues...
but relays are a plain vanilla item available from many sources.
As is the transformer.

Look for 24V coil, enough (resistive) amp rating to handle your load
and enough poles to handle the number of circuits you have.
That will likely mean multiple 2 pole contactors. Like these:

Attached Images

 

biggles

just touch the 2 low voltage wires at the old stat location..together your acting like the stat and the clicking will be a relay or as the contactor shown there.mount 23 of those relays inside a enclosure near the circuit breakers for the 3-240V feeds to the baseboards... cut the contactors in series add a 40VA transformer to control the contactors.biggest thing is the run of stat wire from each room programmable to the contactors...all aailible at your local Grainger supply.if not you your electrican could do this real easy and should know how to do it