I have 2 armstrong heat pumps. One for the upstairs and one for downstairs. They are both about 3-4 years old. The thermostat for the upstairs unit stopped working so I replaced it with a rightemp. The unit upstairs no longer will turn on... I switched the thermostat out with the one downstairs and it works just fine, so I know that the thermostat works. I have checked the power from the circuit breaker to the outside compressor and the inside unit as well and the both have power. I am at a loss. I have tried new wires from the thermostat to the unit and still nothing. Any advice would help a lot.

Thank you
Matt G.

Did you hook up a blue wire? Or put a jumper from rh to rc?

Yes there is a blue wire that I hooked up, in addition to the battery power. The new thermostat came with the jumper already attached. And I followed the instructions to the "t"

OK with the new stat on does the fan on or the heat work? Or is it just the ac that is not working?

Nothing works. No fan, no heat, no ac. Like I said I switched it out with the one downstairs, the old ones, made by armstrong are identical, and still doesn't work. I have placed the new rightemp one downstairs and it works fine.

Did you turn off the power while you were changing stats, may be you blew the little 3 amp fuse on the furnace control board.

The power was off but where is this control board, ill check the fuse anyway.

Should be in the bottom door of the furnace, fuse should be a small 3 amp car type.

I see no fuse in there... I followed all in going and out going wires and looked at all the components in side of the unit.

OK some unit do not have a fuse. Do you have a volt meter?

Check for 28 volts between r and c

Or put a jumper from r to g at the stat and see if the blower comes on.

No I have no voltmeter so I put the jumper between R and G. nothing happened...

sounds like you have a bad transformer. If you are gettting no power.

Other things to check=

Breaker to indoor unit, fuse at switch for indoor unit. Bottom door on good so the door safety switch lets power threw. If these are all good then the transformer is next in line. Inless the is a safety switch on the drain some where.

How can I check the transformer?

Well you said you saw no fuse on the control board. Is there a light on it? If it lights up then you probably have 24 volts if not then probably don't. No other real way to test with out a volt meter.

An LED? I see no light...

Also I see no cca, is that what the switch would be on?

Cca?

Circuit Card Assembly. I assume that's what the fuse and transformer would be on...

Yes a led on the circuit board, its like the fuse some units have them some not.

So I acquired a voltmeter... I checked the transformer, it has the ~220 going in but not the 24v going in. how/where can I get a new transformer?