Community Forums

RJay · 06-11-2011, 08:22 AM

My dash A/C is not working and has never worked. Last year I added some refrigerant with leak detector and although I saw some improvement it didn't last. I know it takes more than just a couple of cans to fill the system but I didn't want to fill it if I had a leak. I now know I have a leak, so before I go on a random search I'd like to start where leaks are most likely. I've verified the clutch is engaging the compressor and since I saw a slight improvement when I added the refrigerant I'm reasonably sure the compressor is working and all compressor connection show no signs of leaking. I'm assuming the two hoses that leave the compressor is a continuous run to the front of the RV so I'll save getting under the RV and tearing into all the coverings for last. Also the schrader valves don't seem to be leaking. So before I start taking things apart, what have I missed, where should I look and what should I look for? Thanks.

**Petro** · 06-11-2011, 08:55 AM

RJay;

I wish I could answer your question but I can't because I have had similar problems. Since I purchased my coach in 2005 I have had to add freon every spring. It would work all summer but need freon every spring. Last year out of frustration I replaced the evaporator coil and compressor. This spring it needed freon again. We have dyed it, sniffed it, and cussed at it and we can't find any leaks. The Tech thinks the seals in the compressor shrink in the cold winter months and it leaks out during the Dec - Mar period. I don't know how I can check for that. If I start it up in Jan and run it down to the shop by the time I get there and get it in the shop it will have warmed up and they still won't find anything. Let us know what you find and I will do the same.

Don

bigskymt · 06-11-2011, 09:18 AM

The 134 with dye is widely available and UV detectors are cheap at Harbor Freight as well as on-line. That might be the best way to go if you can't find any oil residue around fittings or lines.
You might look at/around the condensor. It's exposure to road hazzards, especially if the cooling fan is in front, increases it's failure rate.

RJay · 06-11-2011, 09:22 AM

bigskymt,
Thanks for the suggestion about the UV detector. I was just visually inspecting the system but the UV detector will be more revealing. I'll also be sure to check the condenser.

TXiceman · 06-11-2011, 04:06 PM

The UV leak detectors are for larger leaks in my opinion. Or you have ot keep looking and checking until you finally find a leak. It does require a UV lamp and it warks best in low light conditions,,,not mid day.

Your best bet is to get some one with an electronic leak detector (that knows how to use it) to go over the system and do not forget to check the evaporator and condenser coils.

Ken

Mike Canter · 06-11-2011, 04:26 PM

I have found small leaks in several cars and friends MHs using UV dye. It is important to also use the special orange/yellow UV glasses with the UV light source. I have found it almost impossible to see a small leak without using the glasses. I like search for the leak at night. The worst place to have one is in the dash evaporator coils and the only way you can see that is to check for dye on the condensation drain. Most of the leaks are in the schrader valves where you check the pressures.

Skip426 · 06-14-2011, 12:56 AM

RJay, I don't think it's advisable to assume the freon lines are one piece the length of the coach. Can you access a parts catalog to check that out ? I hope that all the freon isn't getting out, if the system is totally empty and humidity gets in , it will kill the compressor.

gbs2320 · 06-14-2011, 03:37 AM

Quote:

Originally Posted by Skip426

RJay, I don't think it's advisable to assume the freon lines are one piece the length of the coach. Can you access a parts catalog to check that out ? I hope that all the freon isn't getting out, if the system is totally empty and humidity gets in , it will kill the compressor.

I always heard it would kill the drier not the compressor. The drier is often automatically replaced whenever the system is open to humid air.

Mike Canter · 06-14-2011, 07:11 AM

Both my high and low freon hoses from the front to the back are one piece. A small leak is not going to let humidity into the system and you have to evacuate the system anyhow which removes the moisture. It it is highly recommended that you replace the receiver/dryer if you have opened the system up and the MH is a few years old. They vary is price from $25 to $65 so that is cheap. Humidity will not hurt a compressor because like I said you are going to evacuate the system anyhow.

I would believe that the highest probablility is that the leak is either in order of probablity a schrader valve, an oring at a connection or at a swedge fitting at the end of a hose. Not many times you will get a leak in the middle of a hose. Not impossible but not very probable

KJINTF · 06-14-2011, 08:11 AM

I went through something similiar. Found the "cheap" Delphi Clam shell designed compressor had a very small leak. Check under the compressor on top of the engine. They are prone to leakage at the "O" ring that seals the two halfs.

TQ60 · 06-14-2011, 03:50 PM

What did it have when new?

If it was R12 and upgraded to R134 and the hoses or seals were not replaced then this is normal.

The molecules of R134 are a lot smaller than those in R12, they actually seep through the hoses, there are special barrier hoses used for R134.

The O-Rings need to be green, if these were not changed then they may seep too.

Shaft seal on compressor is very common as it dries when not in use, but since winter is time when rig is sitting it has time to leak, it is leaking over the summer, but you do not notice and thereis still enough coolant to keep the compressor safety switch activated.

A leak detector may not help, clean everything with good degreasing soap, rinse well then install a coulple cans of dye, over time you may spot the dye, and have a clue.

Good luck!

Mr JP · 06-14-2011, 08:32 PM

I have had to chase the problem of no cold air. I thought I had leaks and vacuumed down the system then recharged & used a UV detector and found nothing. Still no cold air. I finally put a ball valve on the heater return line to isolate the hot water altogether. Now it works!!!! The inlet valve was even holding drip tight. I also have concluded the Evans Tempcon system is just an ok set up. Good Luck JP