Discontinued Boiler HELP with wiring.

Playtes

I have a hydrotherm gas boiler (Model GW-743). In contacting the manufacture they inform me the boiler was manufactured in Canada by a company who is not in operation. They also could not locate any manuals. I have purchased an electronic theromostat to replace my old mercury thermostat. In removing the old thermostat, I only have my blue and white wires for the heating system (no air conditioning in the house). My question and problem is in running a new wire from the new thermostat to the boiler, I can see where to connect the blue and white, but do not know where to connect the common wire to power the thermostat. Any suggestions?

NY_Rob

If you don't specifically need a programmable t-stat, you can still purchase simple 2-wire mechanical thermostats at the big box stores for under $20.

There are even programmable t-stats that run on batteries so you don't need to add a "C" wire for power.

Jamie Hall

There isn't a place. If you really want a thermostat which needs the C wire to power it, you will also need a 24 volt transformer and a relay.

Or stick with a nice two wire thermostat...

EBEBRATT-Ed

If that is a millivolt system @Jamie Hall is correct. Stay with a two wire stat or get ready to do some wiring, add a transformer, relay etc.

ratio

The blue & white go to the thermostat? The third terminal on the gas valve must be the common. The terminal with the white wire on it is the hot from the xfrmr (not connected to the gas valve, just for making the connection), the blue is the W terminal to open the gas valve, the last terminal is the common for the gas valve.

Playtes

Thank you for your replies. I was hoping to have this one installed as it is wifi compatible to control with my smart phone while away from home. I couldnt find a battery operated one.

Fred

What's wrong with setting the thermostat and letting it do its thing? Why do you feel the need to talk to it and/or the boiler when you're not home?

BobC

I agree with you Fred, the only thing I want connected to the internet is my computer. The internet of things opens us up to every wacko on the planet.

Bob

Playtes

WIth my old mercury thermostat it is set a specific temperature. With our energy costs in Ontario, Canada (highest in North America), I wanted a programmable thermostat that I could set to have lowered at times when we are sleeping and not at home. Also, since I travel frequently, the wifi option was an added bonus to increase the temperature remotely when I was an hour from home while on the road. All this was done to try and be more efficient in energy usage and more importantly to try and lower the utility bills each month. Hopefully that answers why I decided to change my thermostat. I will continue to look for a solution to my problem. I appreciate the helpful replies!

NY_Rob

If you still desire a powered t-stat... see Jamie Hall's answer in post #3.
In addition to the parts he mentioned... you'll need a new cable run to your t-stat.

Best to have a professional do that work IMO.

Solid_Fuel_Man

For just a simple programmable thermostat, just get a battery powered one and leave all else alone. I find the batteries to last around 2 years. Not an issue. It's just the WiFi thermostats which really need the common wire as they are power hogs, so they can communicate.

This is just what everyone else has said.

Taylor

Jamie Hall

I can understand why some might want a wi-fi thermostat -- particularly in Ontario (the hydro rates up there are a scandal). Only thing I would ask, if you do get one -- get a really good one, and please, please change the password to something really secure...

Leon82

I think they have a transformer that will plug into the wall for this someone posted here once.

Could have been amazon or eBay