Replacing White-Rodgers Thermostat, Help.

Dallas79

Hello.. Im trying to replace this old White Rodgers Thermostat with a new Honeywell digital thermostat. Easy enough Ive done this many times before in others houses, but now I have run into my first one that does not have the wire connection terminals on the old thermostat labled. I took it off the wall there is nothing on the back side either. so its a guessing game right now to me. the furnace is a simple 2 wire hookup, but im kinda stumped as to which wire goes were on the new thermostat.

Anyone have any experience with these ones or is it safe for me to just trial and error hook up the new one? id rather not.

here is a pic of the new one.

ben's plumbing

blue on rh white on w....good to go yes leave jumper in place

Dallas79

awesome thanks a bunch ill try it out tomorrow morning when i get back to the house.

ben's plumbing

ok let us know how you make out..

Dallas79

Hooked it up like you said, the furnace is not kicking in.....

ben's plumbing

check for 24 volts on blue to ground.....did you shut off power to furnace before you changed stat?....how old is furnace..may have blown fuse on control board..

Dallas79

I think I may have connected it wrong. Do you put the wires into the back of the little slots or up through the big hole and down in like were the jumper is, I can't get the screws to lock down the wires. So it wasn't working cause when I put the face plate on it just pushed the wires out the back......

Dallas79

Yea I turned the furnace switch and breaker off when messing with it. I tried with the jumper ,without the jumper coming through that little window and into the screws, in from the back. I even reversed the wires to see I that did anything, and nothing, I just put the old on back on the way and furnace is working fine.....

All I can thing is the prongs on the front plate are not getting to the wires. So it's probably and error there. I messed with it for a few hours.... Stumped????

kilosos2

You put the wires through the top where the Letters are. Your old tstat did not really say which is R power and what is heating based on the picture. How many total wires you have coming from the furnace?

how

All the new thermostat has to do to make the furnace work is to connect the R line to the W line. You've confirmed with the old thermostat that your furnace & thermostat wiring is good.
Does your new thermostat have heating modes or switches that are off or is on cooling rather than heating?

Dallas79

I only have those 2 wires coming up from the furnace. One thats almost blue and the other that is pretty much off white. That's all that's inside the black casing that's coming up through the wall. At the furnace I see we're they connect to a little terminal block.

The new thermostat has.( Heat off cool) For one switch and the other is (auto fan on).

When I set tr new one to heat and turn it up I hear the thermostat click but the furnace doesn't turn on.


I'm just not making connection, it's all I can think.

It's a Honeywell 5-2 programable... Model number rth230b

hvactech126

you may have bent the prongs on the thermostat. make sure they are all straight.

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Dallas79

Had a friend come over and he messed with it for a bit and all of a sudden the furnace started working with the blue wire in the Rc and the jumper there but loose on the Rh and the white on the w. then a couple hours later we decided to secure it and the wires came out and it has not worked since in any configuration.

We are thinking its a lemon thermostat so going to try a different one tomorrow.



The furnace is about 30years old, natural gas with electric ignition.

kilosos2

See if you can find a local hvac supply shop and pick up a toptech or pro1iaq tstat. They have nice big display screens. Just hook it up the same way again. Your blue wire to R and White wire to W.

Dallas79

Success!!!

I exchanged the new Honeywell rth230b for a white-Rodgers 750 comfort-set.

Blue into Rh and white into w, furnace fired up right away. All that trouble yesturday and it was the unit itself....

Thanks to everyone that helped no more mercury switch in my home.