Had a storm recently, power went off. When the power came back on, the AC wouldn't. I can't even get the fan to come on without turning on the blower switch on the unit. I have replaced the thermostat, I have replaced the wiring between the thermostat and the unit. The compressor will work if I manually hold the circuit closed. I checked during the cooler nights we had recently and the furnace will not come on by itself either.

WHAT DO I DO NOW???

 

I take it you have either Gas or oil heat... look in the control box, ( place where T-stat wires hook up) and look for a little fuse...

 

DUH...what a dummy I am.... you said you had a heatpump.... Look for a fuse in the fan coil section ...

 

quote:<HR>Originally posted by R-12guy:
DUH...what a dummy I am.... you said you had a heatpump.... Look for a fuse in the fan coil section ...<HR>

Okay, talk me through this, I'm a pinball mechanic, not a heat pump repair guy. Where in the "fan coil section" should I look? And to make sure I'm looking in the right place, which IS the "fan coil section", the sucker on the top behind the filters, or what?

And no, I won't call you a dummy, you're the only person willing to put your two cents worth in...

I'm REALLY glad I stuck this out. I'd feel like a total moron if this turns out to be a fuse and I called a service tech out...

 

the fan coil is the section inside, yes the filter is there... turn off the breaker and remove the panel where the wires are leading in to. there should be a control box, with all the electronics in it... look on the control board and there could be a ATO fuse on it...some thing else you will want to check is for low voltage power.
What brand is it?

 

The unit says Nordyne. Mobile home unit a little over 6 years old. Got one piece on top, I guess thats the inside heat exchange, triangular shaped job with the filters on it, and the blower motor with a junction box mounted in front of it sitting on top of another box, I figure the heater coils are in there. I pulled the cover off the small box in front of the blower and checked the continuity all through it a few days ago, all was okay, no fuses in that one.

 

The unit says Nordyne. Mobile home unit a little over 6 years old. Got one piece on top, I guess thats the inside heat exchange, triangular shaped job with the filters on it, and the blower motor with a junction box mounted in front of it sitting on top of another box, I figure the heater coils are in there. I pulled the cover off the small box in front of the blower and checked the continuity all through it a few days ago, all was okay, no fuses in that one.

 

do you have 24 volts on the thermostat side

 

Tell me where to check and I'l be happy to tell you what voltage I've got(which wires and where, remember I'm a pinball mechanic...)

 

pull the cover off your thermostat... check for voltage at R & G...should be 24V

 

I checked, got absolutely nothing...

Now what???

 

you will have to go back inside the furnace and check for power too and from the transformer

 

No problem, as soon as you tell me where&how...

 

ok...do you have 240 Volts at the furnace? do you know how to use a voltmeter? do you know what a transformer is, or looks like?

 

Checked power at furnace, no, but I did at the outside unit-IT has 240. Yep, I've got a multimeter and know the basics. Yep I know what a transformer is, big-@#$ed metal frame with paper wrapped core. Not exactly sure where to check for the power. Is this transformer inside the furnace itself or mounted somewhere around it?

 

it should be in the control box in the furnace, its not that big .... maybe 3"x3"

 

I know I'm the type you really love dealing with... The type that knows enough to REALLY screw things up...

Not sure where to check on transformer for power. Is it supposed to have 240? With only the breaker on and the thermostat set to have it running?(Yes, I know that last one is a pretty dumb question, but I like to be careful)

 

I know I'm the type you really love dealing with... The type that knows enough to REALLY screw things up...

Not sure where to check on transformer for power. Is it supposed to have 240? With only the breaker on and the thermostat set to have it running?(Yes, I know that last one is a pretty dumb question, but I like to be careful)

 

I know I'm the type you really love dealing with... The type that knows enough to REALLY screw things up...

Not sure where to check on transformer for power. Is it supposed to have 240? With only the breaker on and the thermostat set to have it running?(Yes, I know that last one is a pretty dumb question, but I like to be careful)

 

I know I'm the type you really love dealing with... The type that knows enough to REALLY screw things up...

Not sure where to check on transformer for power. Is it supposed to have 240? With only the breaker on and the thermostat set to have it running?(Yes, I know that last one is a pretty dumb question, but I like to be careful)

 

yes ... you will need 240 on one side and there should be 24 on the other

 

Sorry I haven't gotten back sooner, the desktop beast went down for a couple and I had to do some serious upgrading. Now as for the transformer. I had never seen a PLASTIC transformer before tonight! Voltage on the into side is reading approx 265-266(is that within the acceptable range?) Voltage coming out is pegged right at ZERO. I am taking for granted that this is a problem...

I checked the fuses too. I only found 4 HUGE things, the smallest being the size of my little finger. I haven't taken the upper unit completely apart to find a logic(circuit board). It's set in an inverted vee and I'm not sure how to take it apart without practically demolishing the thing.

I'm replacing the transformer in the morning, hope that's the problem.

If you can think of anything else I need to know about, I'd really appreciate the warnings.

And, THANK YOU FOR ALL THE HELP SO FAR!!

 

let me know how every thing goes...as far as the voltage...thats on the high end....could be one reason for failure

 

Well, if there isn't a way to step down the voltage, and the new one lasts as long as the old(6 years) I guess I can't complain too much...

Wish me luck! I'll tell you how it goes.

 

OK, installed new transformer. Made sure everything was off before I turned the power back on-thermostat, fan, blower, whatever.

Turned power back on. Heard "buzz...POP!"

Am in the process of figuring out what went. It isn't the big fuses, still have continuity. Haven't gotten much further.

Any ideas?

 

Transformer?