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jnwhite · 06-03-2021, 07:36 AM

Well my motorhome is having sympathy pains with all the other motorhomes having basement air problems in these threads recently. I went to test the AC the other day and Compressor 2 is not working and drawing way too much amperage instead of the normal 12 to 13A. Uh Oh!! It was working fine last Fall at the last use. Amazing things break without use, but age and lack of exercise kills stuff too.

I opened the hatch and electric cover for the first time yesterday and the start device (PTCR and CAP) was melted to pieces and scorch marks all over the vicinity. See attached picture. I ordered a full set of caps and start devices due to the age of the unit. Will see if that fixes it, or if the compressor is locked up and I have to drop the whole unit. What a PITA. At least it is a well plowed road thanks to Duner and others who have had this before me.

Jay

Xmcdog · 06-03-2021, 07:44 AM

Before you drop the bucks on the starting electrics, I would check the compressor electrically. Test for each compressor terminal to ground and between each terminal for conductivity.

jnwhite · 06-03-2021, 09:48 AM

Yes, I will do that testing tomorrow after the rain storms pass. I have been wanting to replace all the caps anyhow and keep the old ones as emergency spares so not a waste. I also got a set of caps for the house HVAC as they are 22 years old and are rusting out.

My unit model number is 6537B871. It is a top intake, so will fixing rather than replacing. At least the unit is not rusty as some others have had.

I will add to this thread as I dig deeper.

Jay

spyderRV · 06-04-2021, 01:18 AM

I had a PTCR resistor burn like that and it caused the hard start cap to stay on, which caused the compressor to pull too many amps and blow the breaker. I replaced it with a Suppco SPP5 and it worked fine after that.

jnwhite · 06-05-2021, 08:23 AM

Thanks! I saw people using the SPP6 in another thread and ordered one. The SPP6 is $11 and the Airxcel direct replacement is $33. Since I am not sure the state of the compressor yet, I prefer to risk the less expensive part. Such is the economics of retirement :-)

The Supco one should be easier on compressor starting too. Parts due in a few days.

Jay

NeilV · 06-08-2021, 07:37 PM

To me its better to address the root cause which most times is long term marginally low voltage from poor campground wiring systems, worn receptacles at the power post and too much variance from the utility companies.

I stopped having these type of failures after installing a voltage correction device such as the Hughes Autoformer. I find that a better solution since if addresses every electrical component in the coach and not just the air conditioning compressor start circuit.

51chevy65 · 06-08-2021, 07:51 PM

I had issues with our 2008 Meridian with air conditioner drawing too much current and not coming on like it should so I replace capacitors issue was solved. It was the second unit that was the most problem and also with the blower motors but the capacitors did the trick. Since then we have traded for a 2012 36 M Journey with rooftop units they cool very well but make a little more noise then they basement air. I wish Winnebago would have kept the basement air but they said it was no longer feasible. Now it would make it tough to get new units I've even seen some with rooftop air on them that have the basement are also

Duner · 06-09-2021, 12:47 AM

Quote:

Originally Posted by NeilV

To me its better to address the root cause which most times is long term marginally low voltage from poor campground wiring systems, worn receptacles at the power post and too much variance from the utility companies.

I stopped having these type of failures after installing a voltage correction device such as the Hughes Autoformer. I find that a better solution since if addresses every electrical component in the coach and not just the air conditioning compressor start circuit.

NeilV X2!
I've had the Hughes Autoformer for 17 yrs on this coach and never had a start circuit for the compressors replaced yet. I did replace the start/run cap for the outdoor blower motor last Dec, $11 on Amazon. Since the Outdoor blower starts twice for each startup sequence, I figured that's why it only lasted 17 yrs (10 yrs fulltiming) while the indoor blower motor and the two compressors are still doing fine with all the original parts. I've been to many rv parks where the 30 amp voltage on a hot day is closer to 100 volts and drops a lot more on A/C startup. What a killer for all the A/C startup components and makes the induction motors run very hot too, shortening their life.

God luck,
Bill

jnwhite · 06-09-2021, 08:00 AM

Thanks for all the comments. I don't know the whole history of the motorhome as I bought it used a few years ago. The system was working fine in Fall during winterization and was dead when I tested it recently. It is plugged into my house and the voltages are fine here. Who knows what happened to it at various campgrounds, but I test voltages when I hook to pedestals.

All the caps seem to be original from 10/2006 so could easily be going bad. I am replacing them all. The last ones are due Friday and then I can get busy testing.

Jay

jnwhite · 06-09-2021, 08:58 PM

I thought just occurred to me. If I drop the whole AC unit to do bearing maintenance, is the secondary fuel filter accessible behind it?

I have been loath to change that filter through the bedroom hatch in case I manage to fumble finger it and spill diesel fuel on the carpeting. The DW would NOT be amused. Changing it while the AC is out, if accessible, would let me change the filter and add the primer punp I bought with less risk.

I saw FireUp's picture with AC out in another thread, but he doesn't have the secondary fuel filter. I have the C7 with two filters.

If anyone knows, I would appreciate it.

Jay

jnwhite · 07-10-2021, 09:54 AM

Well I had a break in the heat outside today and worked on the unit. Replaced the run caps (30uf) and the inside blower cap (7.5uf). I replaced the burned up start units and caps with Supco SPP6 start caps. That fixed my problem. Both compressors run fine now. 20 amps with both on and inside fan on high (Intellec shedder reading on Generator) Voltages on all legs (Home AC and Generator at 120V). Was 81 deg outside with the MH in full sun. 48 degs out of the registers inside with both comps on.

Supco SPP6 larger and a close fit. See pics.

Jay

kb2ztx · 07-10-2021, 06:04 PM

Any chance you have links for all your parts you replaced. Mine is a 2003 and figured if Im going to pull it to clean, lubricate etc Id like to replace all of them.

Ray,IN · 07-11-2021, 12:24 PM

Jay, if you ever need to replace your 6537, the 6535 air and heat pump is, I think, a direct replacement. I have both service manuals if needed.

Quote:

Originally Posted by Xmcdog

Before you drop the bucks on the starting electrics, I would check the compressor electrically. Test for each compressor terminal to ground and between each terminal for conductivity.

When we bought this MH #2 compressor would not come on, the fix was to clean the corrosion from the 120VAC wire terminal connections.

jnwhite · 07-11-2021, 07:54 PM

Mine is working good now. I believe the 6535 is a back intake and the 6537 (mine) is a top intake. There is another thread where a poster is trying to make duct adapters to swap the 6535 into a top intake MH as the 6537 is no longer available, but some structure is in the way.

Looks like my unit is currently still repairable with many parts still available including compressors. I am glad the caps fixed my unit. I was not looking forward to dropping the unit and finding someone to solder in the compressor.

Jay