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Ray,IN · 08-07-2022, 04:10 PM

There are actually two separate and equal cooling systems within the box. Their only connection is #2 will not run unless #1 is already running. Of course they share the same fans and refrigerant coils but you get the theme.
If you swap the caps and #1 does not run, you found the problem.

There is a caps testing method to determine good/bad.

MrMark52 · 08-07-2022, 04:18 PM

Quote:

Originally Posted by Ray,IN

There are actually two separate and equal cooling systems within the box. Their only connection is #2 will not run unless #1 is already running. Of course they share the same fans and refrigerant coils but you get the theme.
If you swap the caps and #1 does not run, you found the problem.

There is a caps testing method to determine good/bad.

A meter won’t load a capacitor in the same way as an inductive motor will.

You can try to measure, but i wouldn’t trust the results.

kkocan72 · 08-07-2022, 05:29 PM

Quote:

Originally Posted by Ray,IN

There are actually two separate and equal cooling systems within the box. Their only connection is #2 will not run unless #1 is already running. Of course they share the same fans and refrigerant coils but you get the theme.
If you swap the caps and #1 does not run, you found the problem.

There is a caps testing method to determine good/bad.

Yeah I swapped the run caps earlier today and #1 ran (but went up to 39amps at startup and I don't usually recall seeing a number that high) and #2 tripped the breaker. To rule them out I ordered two new run caps this afternoon (already put in new starter caps earlier this week). If both my run caps are bad and I'm at 14 amps with the 1 compressor (and fans) running then #2 comes on and it takes up to 39 amps like #1 did I guess it stands to reason that I'd see amps in the low 50s for a few seconds before the breaker trips.

Duner · 08-08-2022, 08:54 AM

Quote:

Originally Posted by Duner

The back of the black panel you took off has a schematic of the blower motors and the two compressors and the connections to the control board. I believe the board is clearly marked on the spade connection #1 compressor and #2 compressor. You could swap the #1 and #2 control wires to the relays for each of the compressors. If #2 starts up first and cools down, then at least you know the compressor and associated components are working. If it blow the fuse right away, then it points to the compressor or starting components.

Good luck,
Bill

This is my suggestion from Reply # 11 two weeks ago. Like Ray,IN said, the two compressor circuits are the same.
Did you do this already and found no difference???

kkocan72 · 08-08-2022, 01:38 PM

Quote:

Originally Posted by Duner

This is my suggestion from Reply # 11 two weeks ago. Like Ray,IN said, the two compressor circuits are the same.
Did you do this already and found no difference???

No I have not yet had the time to do this. The rig is parked only a couple minutes from home but it has been a busy couple of weeks. I did have time yesterday to swap the capacitors and that is when I noticed the one is bulging. Swapping power from the capacitors and relays to the compressors making compressor 2 the new 1 is my next project.

Ray,IN · 08-09-2022, 07:00 AM

Replace that bulged cap before proceeding, bulging is one telltale sign it has failed.
ref;https://sanbornsac.com/bad-ac-capacitor-symptoms/

kkocan72 · 08-09-2022, 07:36 AM

Quote:

Originally Posted by Ray,IN

Replace that bulged cap before proceeding, bulging is one telltale sign it has failed.
ref;https://sanbornsac.com/bad-ac-capacitor-symptoms/

2 new run caps on the way as we speak! Based on the #s I was seeing on my ems, the age of the caps and the bulge I’m hoping hey are the main culprit. I have a new fan cap on order as well just to be safe. Plan is to install new caps and pull, if needed, and check all the wiring/connections in the control panel as well.

joemcgin · 08-09-2022, 07:45 AM

Has anyone put together a list of the Cap types needed for both Run and Start Caps? Mine are so old I can't read any info off of them. Thanks.

kkocan72 · 08-09-2022, 11:06 AM

Quote:

Originally Posted by joemcgin

Has anyone put together a list of the Cap types needed for both Run and Start Caps? Mine are so old I can't read any info off of them. Thanks.

Here are the Run Caps rated the same as my original run caps:

https://www.rvupgradestore.com/Colem...-p/69-1226.htm

Here are the start cap kits:
https://parts.unitedrv.com/products/...pacitor-w-ptcr

MrMark52 · 08-09-2022, 01:33 PM

Quote:

Originally Posted by joemcgin

Has anyone put together a list of the Cap types needed for both Run and Start Caps? Mine are so old I can't read any info off of them. Thanks.

Locate the parts manual for your unit and work from that.

Run caps are more critical than start caps and PTC’s.

Most critical is the caps voltage rating. Even though the unit may be running at 120VAC, the cap rating may be either 370VAC or 440VAC. I will not go into the explanation “why” here. Just don’t skimp.

joemcgin · 08-09-2022, 04:48 PM

Thanks!

kkocan72 · 08-11-2022, 05:43 PM

Quote:

Originally Posted by Duner

This is my suggestion from Reply # 11 two weeks ago. Like Ray,IN said, the two compressor circuits are the same.
Did you do this already and found no difference???

Ugh, no luck with the run caps, same problem. So then since I had time I did swap the leads out of the caps/relays to the compressors making compressor #2 the new #1 and vice versa. Started it up and when the thermostat called for compressor 1 to come in the breaker in my house panel instantly tripped.

Took everything apart again and used my multi meter to test the ohms of the leads going to the compressors. #1 tested fine of course, # 2 when testing the 3 leads I did get a "1" on my multi meter which indicates and open circuit, so I definitely have a short in compressor #2, either in the connection/lead to the compressor (I hope) or in the compressor itself.

Looks like next weekend I'm pulling the air conditioner fully out of the unit.

kkocan72 · 08-13-2022, 07:24 PM

Quote:

Originally Posted by Ray,IN

Replace that bulged cap before proceeding, bulging is one telltale sign it has failed.
ref;https://sanbornsac.com/bad-ac-capacitor-symptoms/

Well, pulled the whole unit out. Tested the terminals at the compressor and none showed a short to ground (keeping one end of the MM on a terminal then the other on a part of the coil coming from the compressor.).

The only ting we did not try was seeing if it would start up if I bypassed the thermal protector switch (bottom part of the pic) by connecting the orange common directly to the terminal on the compressor. I checked the thermion protector with the MM and it had continuity so I assume it is good.

My neighbor is a retired electrician and he saw what I was into and came over. He knew his way around everything in the AC unit and felt it is just a bad compressor that is seized up and drawing too many amps.

kkocan72 · 05-15-2023, 12:28 PM

Update: There may be some light at the end of the tunnel.
Didn't work on the unit at all last fall. I was able to recharge the coach AC and between it running and the basement AC on 1 compressor it was more than adequate while traveling even during some 90+ degree humid days. When parked the unit did ok on 1 compressor as long as we kept shades pulled, didn't leave door open and so on.

Last week while at work we had our HVAC tech on site doing our PM work on our rooftop units. The tech and I got to chatting and I showed him a picture of the unit when I had it outside of the coach. He said he would be able to do it on the side some weekend and I could just pay him directly. He has the tools, gauges, access to R22 and just needs me to buy the compressor. He stated he'd come recover the existing refrigerant, remove the old compressor, change the filter, install the new compressor, charge it and vacuum test the system.

So I started looking at replacement compressors. Coleman Mach lists the part as # 1450-2149 but it is very difficult to find in stock and looks to be $7-800.

My existing compressor is labeled as a Tecumseh RKA5512EXA. I reached out to Tecumseh and they did provide me the new model # of the current compressor that will work and told me to get model # RK5EL1AC220J70 which seems readily available for around $450.

So now it looks like I'm going to bite the bullet and buy the new compressor, have the guy do the work and hope that works and saves me some money and I'm not near the $4k replacement cost.