Basement ac problem

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afchap

afchap

Well-known member
Joined
Dec 19, 2008
Posts
1,279
Location
...East TX, or on the road...
Developed a problem today with the basement ac. Came back after a few hours away to find inside hot and AC off. Found "ac circuit 1? breaker tripped. Reset it and turned AC off and back on. When it tried to start, the breaker again immediately tripped. My digital line meter briefly indicated "ground fault" as the breaker tripped. I disconnect from shore power and started the generator to try again. When the AC tried to start it killed the generator.  Neither compressor nor outside blower starts. In side blower will run if switched to "on". I opened the ac unit up and found some heat damage and oil on what the Svc manual identifies as the "fan capacitor". Also noted some points on the circuit board that appear to be browned from heat, though no other damage apparent.

I got a list of local certified service locations, but most/all likely closed for the weekend at this point. Any suggestions on where to get parts/capacitors in Ft Worth area?
 
Oh no!  No suggestions except to look for an AC or appliance parts house.  Might take a few phone calls to find one with the right parts and that's open on Saturday.  Good luck.
 
Paul, it sounds like damage that may have occurred from the AC trying to run on too low voltage over a period of time. Do you have any type of Surge Guard on your rig? I would hate for you to fix the AC problem and have it happen again.
 
Paul,

I would swap the wiring of compressor 1 and 2 on the circuit board. If problem persists on compressor #1 CB, it is probably the out side fan or circuitry involved with the fan causing the problem. If the problem moves to compressor 2 CB the problem is with the #1 compressor. However in this case you have at least one compressor to run on until you figure out what parts you need. Troubleshooting shorts is usually a matter of elimination either by trial or measuring resistance. Could be a bad start/run capacitor for the fan or compressor.
I am not that familiar with the AC wiring on the board to know if this is possible but this is what I would attempt to do to trouble shoot it.

I has to be a significant short, to stop the generator. I don't think the circuit board would do well handling that kind of current.
 
We have a hardwired TRC SurgeGuard ...installed in 2004 after low voltage damage to the AC system. The  SurgeGuard has cut power a couple of times in the past week. When watching the digital line meter I have not seen voltage less than 109 ---normally is 111 or higher. We had plans for the weekend so I opened and turned on all the ceiling vents  and opened the bedroom window a bit to vent the hot air, then got DW and the g-kids in the toad and left. We had a fun weekend at Lake Bridgeport in spite of the heat ...102 was the forecast for today!  Meanwhile I found an RVP certified mobile guy a few miles north of us who said he could help on Monday ...said he normally can get the parts locally if he doesn't have what is needed on hand.
 
If a capacitor is oily or swollen, it is highly likely it is bad. Might be shorted or just failing. Even if just failing, it will make whatever motor it is connected to pull locked rotor. Hopefully, that could be all the problem. It is not unusal for one to go bad. Kind of like light bulbs.
 
Also might mention, if the capacitor has 3 sets of terminals, it most likely is a dual capacitor for both the fan & compressor. Compressor locked rotor would be very high amp draw.
 
UPDATE  ... took all the capacitors to an AC tech today. He checked them and said all test w/i  specs but I did get a replacement for the one that is leaking oil. But it still doesn't work ...acts like frozen compressor. Local certified dealers are booked for weeks. I found a certified mobile guy who can make it tomorrow. If it looks like parts may take long I may just button it all up and drive the 150 miles home where I can deal with it on my own concrete pad. Looks like there are a few certified service place within a 50 mile radius there, OR I'll pull it out myself and have my house AC guy work the compressor.
 
Well, the "certified" mobile guy finally showed about 11am today ...started asking what all I had done so far "up on the roof" ...bad sign. After looking at the electronics, he admitted this is the first basement unit he has seen. How do these places get listed on the RVP service listing online when they have never worked on a basement unit?  The RVP site code indicates "UF" denotes a basement unit certified service center, but several I called told me right up front they don't work on basement units ...at least they are honest over the phone. Others say they do, but obviously don't have a clue when I talk with them, or they actually show up. This guy said he would do some research and get back to me but I have little confidence in his ability to help. Before he arrived today, I swapped compressor #1 and #2 wiring at the relays hoping #2 would start and run as #1, but no joy. I told him if he can't fix it in place, I'll pass. We need to be at home base 150 miles East on Thursday pm so will just plan on a hot drive.  I found a place about 45 miles from home that sounds like a good possibility over the phone ...hopefully they are what they claim to be.
 
Paul,  drive home and get it fixed there.. Open the windows while you drive and experience the wonderful trips we all had before AC's were available. Relive history..

  Obviously a geezer speaking here.
 
Paul,

If you end up getting it fixed at home, do you have a couple of nephews, or neighbors that can help you pull the unit out?  With the unit out, and the lid off, I think just about any a/c guy can fix it.  I had a mobile semi-truck refrigerator repair guy fix mine right at my house.  Less than 1 hour labor and the cost of the freon, I was a happy camper for just $115 out of pocket.

Since your rig is an '03, you have the metal squirrel cage outdoor blower.  I highly recommend changing it out to the composite plastic blower, if you haven't done this already.  Unit runs much quieter and pulls maybe 1 amp less power. 

Also, those sintered brass bushings on the two blower shafts should be replaced with sealed ball bearing ones...about $15 ea at Graingers. 

The procedure I wrote to pull the unit is available on my website and the link is on the left below my profile picture.

Good luck and hope you don't have to sweat too much!

Bill
 
afchap said:
... he admitted this is the first basement unit he has seen. How do these places get listed on the RVP service listing online when they have never worked on a basement unit? ...
Click to expand...

Unfortunately Paul, yours seems to be a common experience with our basement units ::). 

I think Bill has a good plan for you.
 
Open the windows while you drive and experience the wonderful trips we all had before AC's were available. Relive history.
Click to expand...
We have the two g-kids with us and have been telling them of traveling "in the olden days" ...not sure they have bought it yet, but they are about to have the experience!

I do have a nice  covered slab at home, and have thought about the do-it-myself option. My unit slides out the side, so all I need is a cart or table the right height ...may be a good excuse  for a tip to the local Northern Tool or Tractor Supply for a little addition to the shop equipment.  ;D. I've also thought about changing out the squirrel cages. The unit has not been opened since 2007 when the second blower motor was replaced. I'm a bit I comfortable with obvious heat damage to a few wires, and the numerous brown spots on the circuit board. Think I'll have a chat with RVP and my local home AC guys and go from there ...or maybe get the certified tech I found 40 miles away to make a house call (their plug does say "mobile available") so he can do his thing and I can clean up the unit and replace blowers, etc ...plenty of time before next scheduled trip in early September.
 
I reread your post & notice you said the circuit breaker tripped immediately. If that is, as in, instantly, I would suspect you have a dead short. If it hums for 2 or 3 seconds, then trips, I would suspect a compressor not starting.

Overheated wires are normally either bad connections or overloaded.

Many times a circuit board will have brown spots & nothing be wrong with it. Normally it is just control low voltage to relay coils, although some boards have relays plugged or soldered into them.

If you push in one of your main contactors with a screwdriver, you will be energizing one of the compressors, without any input from the circuit board.

If you disconnect your 3 wires from compressor 1 (at contactor, run capacitor, ?) and check with an ohm meter between each wire & the cabinet or ground, it should show open. If not it is shorted. If shorted, you either have a wire touching the cabinet some place or the compressor is gone to ground.
 
Sorry that didn't work Paul. Being the problem did not move to the CB for compressor #2, means there is a problem with the wiring/circuit board used for the #1 compressor. The only good part about that is that you will not be buying compressors. Hope it cools down a bit for you Paul.
 
Finally got the mh to a truly certified tech yesterday north of the little town of Alba TX.. (do NOT trust the rvcomfort website to tell you which places are certified to work on the basement systems ...many who it says are in fact are not, and some will be honest enough to tell you that while others will not...). He just called to tell me the #1 compressor is "burned up & shorted to the case." He has it running on #2 compressor and says all else appears to be good I spite of many brown spots around soldered connections on the circuit board. Don!t know why I could not make it run on #2 by switching compressor connections on the board... He said it would probably take about 2 weeks to receive the new compressor, and I told him to update the squirrel cages to the newer ones while he is at it. The unit has served us well over the past 7 years of full time use other than replacing both blower motors ...one in 2006 and the other in 2007.

I wanted to do this on my home RV pad, but he told me they are backed up apx 3 weeks on mobile calls ...they are located on Lake Fork Reservoir, and there are many RV parks and private sites around the area.
 
afchap said:
.. He just called to tell me the #1 compressor is "burned up & shorted to the case."
Click to expand...

I wonder how he determined the compressor motor is shorted to the case?

Don!t know why I could not make it run on #2 by switching compressor connections on the board
Click to expand...

That doesn't make a lot of sense to me either.

Thanks for checking back in Paul.  BTW - Texas?  Summer?  ???  What's up with that?
 
Guess the "shorted to the case" is his explanation for the immediate breaker trip on shore power, and killing the generator when on genny power ...no sound of anything attempting to start, just the immediate breaker trip.

Texas? Summer? What's up with that?
Click to expand...
That's where our new home base is, and we are between "on-the-road" commitments.  MOST IMPORTANT, the house does have a working AC!!  :)
 
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