My Cockatoo got out of her cage a few weeks ago and 'ate' our Honeywell non-programmable thermostat off the wall. She has done this before, but never down to the base plate. This time she got it down to the wires coming out of the wall and was lucky to not have been broasted in the process...

They have discontinued the model of thermostat and I tried a couple others but they dind't seem to work. At that time the Bryant unit still had the little red light flashing inside and it would power up.

With this cold snap down here in Florida we are desperate to get this thing working, but being school bus drivers, have little funds to do so. So it's a do it yourself world.

Anyway, I have found a replacement thermostat and have put this on correctly. Still nothing out of the Bryant. I had the power shut off to it from the breaker for over a week while I got through the holidays with some space heaters, but even before this, there was no more red light, no sign of life from the Bryant except that I do, when powered, hear a "hum". (There is a little safety switch in the front that when the face plate is off by the circuit board, it cuts power, but this has all been set up correctly.)

Possible bad news is the bird may have crossed wires in her play with the thermostat... or we did when trying to install the first two replacement thermostats. My nephew was able to get a power read off ithe red line on the thermostat with a multimeter at first. But there's none now.

Does anyone know about these units and what I might do to reboot it or.. Troubleshoot the problem? If some wires got hooked up incorrectly in a thermostat what would have gone wrong? How can I tell if the circuit board got fried? Is there some kind of reset button or process with this unit?

The Bryant is in the attic with a large air handler attached and a Trane air conditioner unit outside the garage. This Bryant apparently is the central part of the heating AC system. Also, noteworthy, is the unit was converted with a kit for use with propane gas by the prior owners of the house.

Guess that's all the information I have at the moment. Any ideas?

Tarey

Look for a blown low voltage fuse, typically an automotive type fuse on the PC board.

It will be a 3 or 5 amp auto fuse on the control board that will blow when the 24volts is grounded. You will need to find the short to fix the problem. If you did not turn the power off first to the system before trying to replace the thermostat that may be the reason for the blown fuse.

Thanks! - checking this out and will post the results asap.

Tarey

Ok. Changed fuse (breaker off). Put cover on. Breaker back on. Hum but no message light. I read something on the door panel that the warning light programming wipes out if power is removed for 48+ hours which is definitely the case here. So thinking it might still work, went to the thermostat to turn on first AC (waited 5 minutes, nothing turned on) and then heat (waited another 5 minutes - nothing). Any ideas as to what I might try next?

Quote:

---

Originally Posted by Tarey Wolf

Ok. Changed fuse (breaker off). Put cover on. Breaker back on. Hum but no message light. I read something on the door panel that the warning light programming wipes out if power is removed for 48+ hours which is definitely the case here. So thinking it might still work, went to the thermostat to turn on first AC (waited 5 minutes, nothing turned on) and then heat (waited another 5 minutes - nothing). Any ideas as to what I might try next?

---

Is there any way to analyze where the problem rests - ?:eek:

If you've changed the fuse, and there's STILL no solid red light (indicating power) then the fuse is open again, and you have a dead short. Look closely at the wiring and see if the R wire (regardless of color, I'm talking terminals here) is shorting out against the C wire.

If you have a meter, check for 24-26VAC between R and C at the thermostat. If none, check transformer at secondary terminals (pull wires off board to test-don't let them hit the cabinet or any metal!) If you have no power out of transformer, but you know there's 110volts to the system-it needs a transformer. 110 to 24VAC 40VA rating.

I'm not intimate with this furnace, but the Carrier units I am familiar with use a solid red diagnostic LED to indicate "Power On" to the board.

If you can't find the short easily, you may have to get a tech in after all.

Ps... some techs will use a 75VA transformer with a built in breaker to power units if they have nothing else on their truck. Look at the transformer and see if it has a little breaker button marked "3.2A". If it's tripped, reset it and try again.

I wish you luck, but I believe the problem is going to be out of your reach, and you will in all probablity have to find a technician. Best wishes.