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?

On Feb 29, 5:54*am, topswage wrote:
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?

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

On Feb 29, 8:37�am, ransley wrote:
On Feb 29, 5:54�am, topswage wrote:

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?

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

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

On Feb 29, 5:54*am, topswage wrote:
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?

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

topswage wrote:
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?

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.

"topswage" wrote in message
. ..
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?

I don't see any reason why a digital electronic electric heat thermostat
wouldn't work. You have to be certain to get one for single pole, and one
that doesn't require a neutral. They're available, I've installed them.
There is another way you can go, which is how typical systems like yours are
wired. You need a switching relay like Honeywell R845, they cost about $50.
The 120 volts that's currently feeding the circulator and being broken by
the line voltage stat, would power the relay. The cable going to the
circulator gets connected to the switched load of the relay, and you can
either run thermostat wire from the TT terminals of the relay to any series
80 (standard 24volt thermostat) that you like, or even use the existing line
voltage cable for your thermostat wire

On Feb 29, 5:54 am, topswage wrote:
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?

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

http://cgi.ebay.com/Programmable-Lin...QQcmdZViewItem

JK

On Feb 29, 1:13*pm, jJim McLaughlin
wrote:
topswage wrote:
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?

* * 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.

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

"Big_Jake" wrote in message
...
On Feb 29, 5:54 am, topswage wrote:
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?

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

http://cgi.ebay.com/Programmable-Lin...QQcmdZViewItem

JK

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.

Joe wrote:
On Feb 29, 5:54 am, topswage wrote:

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?


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

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

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

"Nate Nagel" wrote in message
...
Joe wrote:
On Feb 29, 5:54 am, topswage wrote:

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?


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

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

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

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