Ruud heat pump problem - Please help!

[crmont]

Still no further codes?

[TLHaddix]

At long last, it is fixed. It was the expansion valve. Has been fixed two weeks now. Thank God! Knock on wood.

Thanks to everyone who tried to help. I do appreciate it.

[surenuff]

Seems like a lot of work and wrong diagnosis to end up with a bad TXV.

[TLHaddix]

Hey, everyone. Guess who is back? Yep, me again.

So the heat pump worked perfectly after the reversing valve was replaced....until two months ago. Maybe three. Time flies when you're having fun, right?

Here's the new deal. It blew a low-voltage fuse on the outdoor unit. Aside from some very minor grunting, and I mean very minor, about a month prior to the blown fuse, it was fine. So my guy comes out, replaces the fuse. Then the fuse on the indoor unit blows. He comes out, replaces it, thinks there has to be a problem with the defrost board, because I think it actually blew a fuse while it was in defrost. Orders new ones. I switch to emergency heat, the boards come in (he replaced all the boards, just to be safe), and it runs for a few hours normally. Maybe even a couple of days. Then it blows the outdoor fuse again.

He comes back out, scratches his head, says it could have been the fan motor, as the fan didn't want to start back up once they replaced the first fuse. So we replace the fan motor. Didn't fix it. Blew another fuse. Back on emergency heat. He talks to his rep, and after that discussion, comes back out, replaces the blown fuse (what is this, five now?), and takes the defrost relay off line.

Unit runs fine for two weeks. We think we have it nailed. The night before he is scheduled to replace the relay, it blows another fuse. (Insert cursing here, his and mine.)

He replaces the fuse and the relay. It runs for a couple of days. Blows another fuse. He comes back out, replaces the fuse. It runs for two or three hours. Blows another one. That was today.

When it is running properly the only thing it does that is out of the norm is grunts. It grunts when it is running in the first stage, normal operation. I'm thinking compressor, he says no. But the grunting....I know it's the compressor making that sound, because that's the same noise it made when it was overcharged. It isn't as loud or severe, but it's the same noise.

So, any ideas? And is it time to just give up and replace the outdoor unit? Call the manufacturer and beg them to replace it? What?

Thanks, all.

[Rodney28334]

I dont see why compressor would blow low (24volt) fuse in either unit. Maybe the insulation on thermostat wire is compromised somewhere and is shorting or grounding out. Could be the boards but they have been replaced so that leans me toward one of the tstat wires. A thermostat wire has thick insulation covering several small wire which have thier on thinner insulation/covering which is easy to tear especially if its been exposed to sun for long period of time. If it runs a while in heat then blows fuse it could be aux heat wire shorted somewhere. As far as the compressor grunting sometimes; we can only speculate unless onsite. Did the tech check pressure or amperage to compressor? It is possible that it could be having issues running so long with bad TXV previously (you said TXV in one post and change over valve in other) What ever caused last txv (if it was txv) to fail could have done same to this one over time as in contaminated refrigerant. But again I think that is seperate from your low voltage fuse problem. Is the thermostat wire going to outdoor unit exposed or in a conduit (plastic sleeve). Ive seen people knick them with weed eater, dog chew on them or it could be rubbing against unit somewhere. I hope it works out as that is too nice a unit to replace this soon.

[crmont]

Previously you said the expansion valve was replaced to fix your initial problem but in your latest post you cited the reversing valve as having been replaced. .. which is it?

[TLHaddix]

Previously you said the expansion valve was replaced to fix your initial problem but in your latest post you cited the reversing valve as having been replaced. .. which is it?

Honestly, I don't know. It's the valve that switches it over into defrost and makes it go into the whoosh.

I called our local distributor for Ruud, explained the whole thing to them, and they think it's a wiring issue. Referred me to a local contractor who is both HVAC and a licensed electrician. I have a call in to them, but can't get them to call me back.

Still haven't heard from my latest HVAC guy who has been doing all the most recent repairs. He was pretty upset when I called two hours after he'd left the last time to tell him it had blown another fuse...but I'm getting pretty aggravated at having a heat pump that doesn't work. We won't even go into the $350 electric bill from running emergency heat the majority of last month.

This makes me wonder if there hasn't been an issue with the wiring all along. It certainly would explain the wonky thermostat.

[crmont]

The initial overheating without a call for heat (your description) could not be caused by a failed RV or TXV.

What I suspect happened was that the outdoor sensor wire was too close to the power circuit or compressor leads of the heat pump. Honeywell has determined that a flaw exists with your thermostat that causes the "running away" of the system and eventual failure of the thermostat when this condition exists.

While I've experienced This phenomenon first hand, I cannot remember if blown fuses were also part of the failure.

Separating the outdoor temperature sensor wires from any 220v circuit is a must with the 8000. If you find that the condition did indeed exist with your system then it's likely that the thermostat may have to be replaced as well.

[TLHaddix]

Okay, the latest - Very, very nice HVAC specialist came out. She is also the licensed electrician. Completely different attitude about getting this thing fixed, and I have hope!

She changed a couple of things around on the wiring (there were a couple extra wires not in use, leftover from install) and she switched the red wire to one of those. (Low voltage.) But then when we kicked on the heat pump, it kept shutting down with a high-pressure alert. (Yes, that is new.) We switched over to AC (as it's 80 degrees here today), and it is running smoothly. She's going to do some research and get back to me, and I'm going to monitor the unit for any changes.

Someone here mentioned something about a filter possibly being stopped up or a line being stopped up - there is a two-way cannister thing on one of the lines, and she is wondering if that could be causing the high-pressure shutdown. (The code for that was 23, in case anyone wonders.) Do any of you know if that can stop up going one way (heat) but not the other (cool)? She's going to do research and find out, but if someone here knows, I can tell her where to go to find the details....

The blower motor is fine, the filter is fine, coil is clear on both units, all the things the Troubleshooter guide said to check, check fine. So the obvious answers as to why we're tripping the high-pressure alert, thus shutting the outdoor unit down for safety, are al negative.

Anyhow, that's where we are at. Still haven't heard from my previous guy, and I'm going to call him, probably tomorrow, and settle up with him.

Thanks for your help, everyone.

[ga-hvac-tech]

I have not read the entire thread... however if it runs fine in AC yet not in HP, and the problem is high pressure shutdown... then there is something specific to the heat cycle.

First... I see either/or/both the reversing valve and TXV (was that the outdoor or indoor TXV) have been replaced. Please specify.

Either there is a restriction in the refrigeration circuit which only happens in heat mode... or there is not enough air going over the indoor coil to extract the heat being sent inside.

Tell you what: Count all the registers and their sizes (separate the supply and return registers), and post the counts... like this:
Supply:
4 vents with a 6" pipe behind them,
4 vents with a 8" pipe behind them,
etc...
Return:
2 vents with a 12" pipe behind them,
1 vent with a 16" pipe behind it.

How to tell what pipe is behind it? Look through the opening and you will see a round area... might take one or two covers off (remove the screws) to tell which size is which until you get the hang of it.

I should be able to give you a rough idea if there is enough ductwork from this.