Replacing a thermostat advice, wiring and what to get

[azzurribaggio]

Ok I took my thermostat apart (I can mail pics if this will help), so how can I tell I have a 2 or 4 pole thermostat here? This thermostat controls two wall heaters, only no cooling. So will the Honeywell T4700 work with my current setup? I'm going to just order it online, because none of the Home Depots around here have either, although I haven't checked any Lowes around here yet.

Basically the two red wires to the thermostat connect to white and black wires in the wall, and the two black wires to the thermostat connect to white and black wires in the wall:


---white----X---red-----O O----red----X---black

---white----X---black---O O---black--X---black


I assume one is power and ground to one heater and the other set to the other heater? I also have a pic of the diagram on the back inside cover of the thermostat.
So can my current setup handle 120/240???

Can someone please give me some advice?

[mattison]

Is this a line voltage t-stat you're trying to replace? Is it for electric baseboard heaters? If it is then this stat should work for you. here is the litrature if you haven't read it. http://content.honeywell.com/yourhome/ptc-thermostats/T4700.htm

[azzurribaggio]

Is this a line voltage t-stat you're trying to replace? Is it for electric baseboard heaters? If it is then this stat should work for you. here is the litrature if you haven't read it. http://content.honeywell.com/yourhome/ptc-thermostats/T4700.htm

What exactly is a line voltage t-stat? I know this thermostat is quite old (probably >20 years old). It controls two electric wall heaters.

Also I'm not sure what people mean when they say 2 or 4 pole thermostats.
I do know I have two white wires and two black wires comming out of the wall attaching to this current thermostat.

[Jay11J]

go ahead and e mail me the pic to jaymarking at charter dot net

[mattison]

Line voltage just means that the t-stat has high voltage running through it "220" as apposed to a transformer being involved and dropping it to 24volts.

It looks like you will want the T4700B which is a 4 wire. A 2 pole only breakes 1 leg of the electric and the 4 pole breaks both legs of the electric and that qppears to be what you have.

Send Jay the picks and he will comfirm it.

[azzurribaggio]

Line voltage just means that the t-stat has high voltage running through it "220" as apposed to a transformer being involved and dropping it to 24volts.

It looks like you will want the T4700B which is a 4 wire. A 2 pole only breakes 1 leg of the electric and the 4 pole breaks both legs of the electric and that qppears to be what you have.

Send Jay the picks and he will comfirm it.

Yup already did! Thanks

[Jay11J]

Got your e-mail

Here is the drawing (http://ww2.imagewiz.net/images/hvac1/184514_drawing.JPG)

The back side with wires (http://ww2.imagewiz.net/images/hvac1/184515_backwire.JPG)

And the back of the old t-stat (http://ww2.imagewiz.net/images/hvac1/184516_backside.JPG)

YOu have a double pole 4-wire t-stat. The way it was wired from your drawing does work, but not the way I would wire it. One question tho, is there two breakers controling this or one breaker for two base board?

[mattison]

I agree. From the schematic it looks like you are using 2 seperate circuits for 2 seperate heaters and only breaking 1 leg of electric to the heater. the T4700B is only rated for 16 amps @ 240 volts.

It will work that way but I think I would look into getting a higher rated t-stat.

I know the T498 is rated up 22 amps @ 240 volts

[azzurribaggio]

Got your e-mail

Here is the drawing (http://ww2.imagewiz.net/images/hvac1/184514_drawing.JPG)

The back side with wires (http://ww2.imagewiz.net/images/hvac1/184515_backwire.JPG)

And the back of the old t-stat (http://ww2.imagewiz.net/images/hvac1/184516_backside.JPG)

YOu have a double pole 4-wire t-stat. The way it was wired from your drawing does work, but not the way I would wire it. One question tho, is there two breakers controling this or one breaker for two base board?

By breakers do you mean fuses in the fuse box? If so then yes, I need to shut off two seperate fuses within my fuse box for the two wall heaters (not baseboards).

[Jay11J]

How many AMPS is each unit itself rated for?

These heater has a fan as well?

FYI, Not sure about your area, but here we get cheaper rate on home insurnace if you change from fuse to breakers. We were told that when we brought our house last fall. I'm planning on taking out my fuse box and upgrade the service amp as well to get a cheaper rate.

[azzurribaggio]

How many AMPS is each unit itself rated for?

These heater has a fan as well?

FYI, Not sure about your area, but here we get cheaper rate on home insurnace if you change from fuse to breakers. We were told that when we brought our house last fall. I'm planning on taking out my fuse box and upgrade the service amp as well to get a cheaper rate.

I have no idea how many AMPS each wall heater is rated for.

Yes they have a fan as well, but they only act as heaters, not a seperate fan.

So my question is, can I go ahead and buy the T4700 Honeywell thermostat to replace my current thermostat with the wiring I've shown you for the two wall heaters I have?

[azzurribaggio]

I agree. From the schematic it looks like you are using 2 seperate circuits for 2 seperate heaters and only breaking 1 leg of electric to the heater. the T4700B is only rated for 16 amps @ 240 volts.

It will work that way but I think I would look into getting a higher rated t-stat.

I know the T498 is rated up 22 amps @ 240 volts

Are there any risk for me getting the T4700b?

[mattison]

On your schematic you wrote "22 amps per circuit". How did you get this number?

If that is what you have the T4700 is only rated for 16 amps. You will more than likely burn it up eventually.

[azzurribaggio]

On your schematic you wrote "22 amps per circuit". How did you get this number?

If that is what you have the T4700 is only rated for 16 amps. You will more than likely burn it up eventually.

Oh I just copied word for word what was written on the inside cover of the current thermostat.

The T498's aren't digital though, I was looking to upgrade and bring my thermostat into the year 2005 :)

[mattison]

You would need to find out what the heaters draw amp wise. There should be a rating plate behind the heaters panel or on the heater itself behind the panel. Make sure the power is off when you start looking.

[azzurribaggio]

You would need to find out what the heaters draw amp wise. There should be a rating plate behind the heaters panel or on the heater itself behind the panel. Make sure the power is off when you start looking.

Ok gotcha....I'm inquiring from a local electrician how much it would cost just to have someone replace this thermostat for me, just so I know it's done right!

[azzurribaggio]

Ok gotcha....I'm inquiring from a local electrician how much it would cost just to have someone replace this thermostat for me, just so I know it's done right!

Ok guys here's an update:

The two wall air heaters this thermostat controls are

Raywall Model # RT2-24T
Volts AC: 240
Watts: 2400

Couldn't really find any AMPs reading

so based on this added info does the T4700 sound like my best bet?

[mattison]

Amps=Watts/Volts

2400W/240V=10Amps

Looks like you're ok.

[azzurribaggio]

Got your e-mail

Here is the drawing (http://ww2.imagewiz.net/images/hvac1/184514_drawing.JPG)

The back side with wires (http://ww2.imagewiz.net/images/hvac1/184515_backwire.JPG)

And the back of the old t-stat (http://ww2.imagewiz.net/images/hvac1/184516_backside.JPG)

YOu have a double pole 4-wire t-stat. The way it was wired from your drawing does work, but not the way I would wire it. One question tho, is there two breakers controling this or one breaker for two base board?

Which one below should I order then? And do you guys know of a cheaper place I ca get this one?

http://www.shop.store.yahoo.com/air-n-water/proghontherp.html