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jimothy12 · Jul 30, 2009, 08:06 PM

My wife purchased a Honeywell rth230b thermostat. I have a gas furnace (bryant Plus 80). The old thermostat was laid out like this:

Red = R
Yellow = Y
Green = G
Blue = C
White = W

I have the rth230b wired like this:

Red = Rh
Blue = Rc
White = W
Yellow = Y
Green = G

I also took out the Rh to Rc bridge because I have a 5-wire system and the J2 jumper is set on HG.

The system has batteries and is switched to cool. The old thermostat worked great until my wife dropped the mother board while removing it to paint. Also the furnace is only a year old.

the fan, AC, or heat won't come on!! What's going on? My wife, 3 dogs, and I thank you.

wmproop · Jul 30, 2009, 08:10 PM

Put the jumper back

jimothy12 · Jul 30, 2009, 08:12 PM

Originally Posted by wmproop

put the jumper back

Why is that? The manual says to remove it for 5 wire systems. Worth a shot. I'll let you know

jimothy12 · Jul 30, 2009, 08:22 PM

Nope. No change.

I haven't set the clock on it yet. Still blinking. That wouldn't matter right?

wmproop · Jul 30, 2009, 08:27 PM

Did you kill the power to furnace? You may have fried the transformer, or blown the fuse in the circuit board

jim5588 · Jul 30, 2009, 08:35 PM

Like an idiot I didn't turn off the power. This has to be it because it looks like the batteries in the thermostat is doing all the work. I think I'll end up calling someone in the morning

jimothy12 · Jul 30, 2009, 08:38 PM

No idea why my user name just changed. Thanks for your help wmproop

KISS · Jul 30, 2009, 08:45 PM

RTH23b manual: http://www.honeywellcentral.com/ssi/...30B_manual.pdf

Turn off furnace!

Remove blue (C) - wirenut or tape and don't use
Put the Rc/Rh Jumper back

But I'm afraid the transformer or transformer fuse is history. Blue to red assured that. Hey, it's only money. Throw more money at it, it might work.

jimothy12 · Jul 30, 2009, 08:52 PM

The reason I connected blue to Rc is because the manual says Rc is Cooling power supply. My old thermostat manual says 'C' (where the blue cable was in) is 24 val com.

Damn it. How much can I expect to spend on a transformer and/or fuse? We are talking about the Furnace transformer or fuse correct?

KISS · Jul 30, 2009, 09:05 PM

Noooo. R is old stiff now. There is a two transformer system that requires Rc and Rh, when there are not two transformers Rch or Rheating and Rcooling. R is actually one side of the 24 VAC transformer and C is the other. Between R and C you have 24 Volts ALL the time. Hence, your connection SHORTED the transformer. (C) is now a needed terminal so that the electronics can be powered all the time.

If your lucky, there is a 3A automotive fuse on the secondary of the transformer, so you lost a buck. If your really luckly, the system has an energy limiting transformer in it. SHorts don't bother them at all. But, I'll bet that the transformer blew to protect the wire.

Transformer:Maybe $50

Rule 1: Muck with wires with unit unpowered.
Rule 2: If you don't understand,don't muck with the wires.
Rule 3: That manual is pretty good.

Three strikes and your wife won't lie it. That's your punishment for being macho. It doesn't work here.

Get a fuseholder and add the 3A secondary fuse if there is not one.

jimothy12 · Jul 30, 2009, 09:10 PM

When I opened the furnace I didn't see any fuses. :(

wmproop · Jul 30, 2009, 09:27 PM

Is hard to see,, on your circuit board, very small push-in automotive type usually a 3 amp
Not all have one,, but look close and carefully