Latest Discussions : HVAC

rkalhan

05:23AM | 12/21/04
Member Since: 12/20/04
2 lifetime posts
Hello --

I am in the market for a programmable thermostat for my condominium.

I was reviewing the documentation of my furnace (TempStar), and it says that it is a 2-phase gas furnace.

I then looked at my existing thermostat which is a RobertShaw non-programmable (model 9500).

I don't think my current thermostat is designed for a 2-phase furnace and in fact there is only a single W terminal rather than W1 and W2. In addition there is a jumper from RC to RH and the wire is going to RC. There also is a G and a Y wire, the B and O terminals are left open.

That all being said, by heating works fine, and I have not had any problems in the 1.5 years that I have lived in my place.

So the question is can I get a similar thermostat that has a single W terminal? I don't even think that I have two W wires coming out of the wall.....

any suggestions are much appreciated.

Thanks.

JGRIZZ

06:19AM | 12/21/04
Member Since: 12/16/04
54 lifetime posts
It sounds more like you have a two STAGE furnace. IF its a two stage furnace, you should just pick up a two stage thermostat.

If you can find a two Stage thermostat, you may be able to order one on the internet.

A two stage furnace basically has two separate burner operations, low heat and high heat. Usually the burners will operate on a call for heat for about the first 15 minutes, then if the room temperature is not satisfied it will kick into the second stage burner operation. Just do a little more research to find that two stage thermostat, one thing tho-when you remove your existing thermostat you need to have an existing second stage wires to stat. You need a w & w1 or a w1 & w2 existing connection. If you dont have the extra wire you need a service tech outthere to connect the second stage in the furnace or possibly bring you a new cable with enough wires to power up the second stage operation. on some furnaces you can override the first stage internally but why.

rkalhan

07:31AM | 12/21/04
Member Since: 12/20/04
2 lifetime posts
even though things are working fine, do I need to get a 2 stage thermostat?

there is not a second W wire to put into the thermostat, and i'm not sure that i want to make the investment for a tech to come out and rewire things - do you really think it's worth it - my condo is pretty small, and heating needs are currently satisfied pretty easily.

thanks - your opinion is helpful.

JGRIZZ

05:36PM | 12/21/04
Member Since: 12/16/04
54 lifetime posts
If it works dont change it! There is no reason you have to change it out, unless the unit does not operate, I mean the furnace may have a built in overide that automatically changes it two a single stage unit with a simple flick of a switch on the circuit board. Again you may need a tech outhere for that, but hey if its wirking and there seems to be no problems, I would not fool with it. Good luck




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