I would like to install a z-wave tstat in the basement - for the most part, to keep an eye on the temp, and of course kick the heater on when needed.
Thing is, I have a 1960’s Sears in-wall gas heater unit (had it checked out and all is good, works well) with a Sears heat only mercury switch thermostat. The installed thermostat is shown in the pictures.
Can I use the CT-30? Picked it up super cheap and would be a shame not to. As you can see, there are only two wires and they aren’t labeled.
I was going to use an external transformer for c-wire too so the tstat would act as a repeater. I see that would go to C and RH.
Well, after much research and delving back into the 1970’s, I can’t use the CT-30 or any other low voltage tstat. I have a ‘millivolt’ (getting 1V actually) thermometer which is what they were using and are still in use today for wall heaters.
I haven’t installed it yet. I was going to wait a little bit and grab a 24V transformer I can put into the wall so I can use c-wire capabilities. It’s my understanding that it can’t be added later with c-wire capability unless you take the tstat off the network then re-install it.
Installed it last night. Used a 24V transformer and ran two wires to C & RC, then connected millivolt t-stat wires to W & RH. It’s nice when you don’t have to worry about polarity.
