Coleman Mach 3 Start Capacitor Burns Up

[A440]

My AC quit cooling yesterday. The fan runs and the compressor trys to start for about 3 seconds and stops and repeats the process again in about 30 seconds. I replaced the start capasitor and everything worked great for about 30 seconds and then the start capasitor started smoking. What can be causing the capasitor to burn up? Could the problem be in the start relay or run capasitor? Help! We are living in the fifth wheel this summer while between homes.

Gary

["007"]

Welcome A440 to irv2.
Sounds like you have to higher voltage feeding your AC. Could be something wrong back at your load center. You need a volt meter to read whats feeding the AC.
LINK info for start capacitor.

[RV Wizard]

A440, welcome to iRV2.com. We are glad to have you join us here and we look forward to reading of your adventures and experiences. I am sure you will enjoy this website and forums.
When you replaced the start capacitor did you also replace the the positive temperature coefficient resistor (compressor motor starter). If not and you find that the windings in the compressor check good and no shorts to ground, you should also replace the PTCR. It sounds like the start windings are staying energized and this will cook the start capacitor and eventually damage the compressor if it is not already.

[A440]

Thanks for the replies. I do not see a PTCR on the unit. All I can find is the start cap, run cap, fan cap and start relay. Is the start relay also referred to as the PTCR? It does not look anything like pictures on the net of the PTCR. The schematic does not refer to a PTCR.
I appreciate any and all help.

[Luv2go]

The start relay does the job of the PTCR on older units. The relay probably is stuck on and will need replacement.

Stewart

[Luv2go]

Our old coach we had a 13.5Kbtu Mach 3 which would draw 17A when running. I didn't think much of it until I decided to look and see if it had a hard start kit, because it wouldn't start on our 2500W inverter.

Well, it did and the relay was stuck on! It had been running this way for two years (since we bought it), and had not burnt out the compressor! I replaced the relay and start cap and the unit was still running when we sold it three years later.

Unit drew 13A with properly operating start relay, also started and ran just fine on our inverter after the repair.

Either we were just lucky or the 1993 Mach 3 compressors were built like tanks.

Stewart

[A440]

My unit is a 2001 if that makes any differrence. I am currently in Kansas and called several rv parts stores lookiing for the start relay and none knew what I was talking about. How do I go about getting one? The start cap is easy as it is a common part found anywhere. I have read on other posts about a Supco SPP6 that replaces the start cap and relay. Anybody have experience with these?

Gary

[Luv2go]

I found the manual for my unit at the manufacture's website:
RVP > Products > Rooftop Air > Standard Height Models

The technical information section hopefully has a manual and parts list for your unit. If you have the model number you should be able to find at least the service manual. The RV parts dept I went through did have to order the relay from the manufacturer. Sometimes they are called "Hard Start kits".

I have no experience with the Supco SPOP6, however I did research it while I was looking for a solution. I went with the OEM part because I could find it but would have used it if I had to.

Stewart

[AFChap]

Quote:

am currently in Kansas

The mfg'er (RVP) is located in Wichita ...you are not far from the ultimate source!!

[A440]

afchap, yes I am about 20 miles from RVP in Wichita. When I contacted them they were not any help. They do not sell directly to the public, telling me that I need to purchase from an rv parts dealer. Yesterday when I went to a dealer in Hutchinson, armed with parts numbers, the lady behind the counter had no idea what a start capasitor or relay was. I also asked about the Coleman Hard Start kit even had part numbers for that as well and she was clueless. She called another dealer who had no idea what I was talking about. Good grief. I think I may try the Supco SPP6. It appears to serve both as a capasitor and relay. I have lived in the Mesa Arizona area for 23yrs and am used to rv dealers seemingly on every corner stocked with knowledgeable people and parts. Does anybody know of a good parts dealer in the Wichita area?

Gary

[AFChap]

Gary

We had a problem with out unit a year ago and RVP refered us to Flint Hills RV at 1523 Ledgerwood Dr (159th St. E. & Hwy. 54) in Andover KS on the East side of Wichita. Their service tech (Darrel) was absolutely amazing compared to others who have worked on our unit. They even hooked us up to power for the night and gave us a key to the gate in case we wanted to go out after hours., AND they got the parts we needed from RVP even when the first answer was that the parts were on backorder! Their phone is 316-733-8300. We have had our basement unit worked on at several different places, and Flint Hills did the job much quicker and better than any place we have ever been. Next time it breaks, I hope we are near Wichita so we can go back to them to get it repaired!!!

[RV Wizard]

Quote:

Originally Posted by A440 My unit is a 2001 if that makes any differrence. I am currently in Kansas and called several rv parts stores lookiing for the start relay and none knew what I was talking about. How do I go about getting one? The start cap is easy as it is a common part found anywhere. I have read on other posts about a Supco SPP6 that replaces the start cap and relay. Anybody have experience with these? Gary

To answer your question the SPP6 will work but you will have to change some wiring to do so. I have been in the electrical and refrigeration/air conditioning business for 35 years so for me it would not be difficult. For those that may not understand how all this works together may not turn out so well. If you have access to the original parts or have a dealer that is to do the repairs; I would recommend this approach.

[MonacoMama]

Quote:

Originally Posted by RV Wizard To answer your question the SPP6 will work but you will have to change some wiring to do so. I have been in the electrical and refrigeration/air conditioning business for 35 years so for me it would not be difficult. For those that may not understand how all this works together may not turn out so well. If you have access to the original parts or have a dealer that is to do the repairs; I would recommend this approach.

I am going to totally disagree with RVWizard on this one if the Coleman works the same as the Dometic AC.
We have done the fix with the SPP6. Please read the complete post about the aftermarket part here.

Good Luck!

[RV Wizard]

To replace the PTCR with the SPP6 it is pretty straight forward. To replace the older starting relay and start capacitor re-wiring will be necessary, eliminating the start relay from the circuitry as the SPP6 has its own capability to isolate the starting capacitor section from the compressor.