120volt thermostat

[topswage]

My home is heated with a gas fired hot water boiler. The system is presently controlled with a 1950's style bimetal thermostat. I'd love to replace the thermostat with an electronic set-back unit, but have discovered that the thermostat is directly controlling the hot water circulating pump--there's 120volt current running through the thermostat, enough to fry most electronic ones. I see though that there are electronic thermostats designed to control electric baseboard heaters, and will control 120 volt circuits--can I use such a thermostat to control my circulating pump?

[ransley]

I dought 120 is going to the thermostat, its likely 12v or so, to a relay. Do you have a Honeywell round thermostat.

[hallerb]

there are 120 volt and even 240 volt thermostats in use today.

ww grainger sells them

call a local HVAC company they should have the set back type, not usually sold in stores because of the hazards installing. line voltage heavy current etc

[Joe]

Honeywell makes ( or made) a kit with a relay, etc. for converting line voltage systems to work with 24 V thermostats. Installed a couple of these in a shop some years ago, so I hope they are still available. That would solve your problem very neatly. HTH

Joe

[Meat Plow]

How handy are you with electrics? Would not be much of a job to convert to a low voltage thermostat using a low voltage contactor like the kind you would find on an air conditioning outdoor unit. This way you wouldn't be limited to a baseboard type and could get as sophisticated or as simple as you want.

[jJim McLaughlin]

What did Honeywell recommend when you E ailed their support function?

Oh, you didn't bother to do that?

What was the result of your Google search?

Oh, you didn't bother to do that?

Why do you think several thousand amateurs on here in an anonymous Usenet newsgroup have an answer to your esoteric problem?

Please make an effort to do your own basic research.

[Big_Jake]

Any of you guys want to tell me why this wouldn't work, as a simple solution?

JK

[Pat]

It is not an esoteric problem. The exact same problem applies to everyone who has electric heat.

[RBM]

That particular model won't work because it requires a 240 volt power supply to operate. They have other models that require a 120 volt power supply to work as well, and they too won't work in his application. He has two wires , a 120 volt hot leg, and a return, no neutral. Honeywell/Aube does make 120 volt two wire models that possibly will work for his application.

[Nate Nagel]

yup, I'd think a doorbell transformer and a relay with a low voltage coil would solve your problem

nate

[RBM]

And it's all contained in a box called Honeywell R845 switching relay. They're also made by Taco, Argo, White Rogers, and a host of others