Newmar AC repair

[DavidL]

While getting my coach ready for our annual trip in October, I ran the motor to air up the new airbags. The dash heat was hot, but it was set that way. I turned it to AC Max and it never got cold. So, looking at the AC compressor, the suction line was disconnected from the compressor (what?). So, I cleaned and put the fitting back on and evacuated the system for hours to get rid of any moisture from the system being open for what seems months (the fitting was seized a bit so it hadn't been turned for a while.

I fed in three 12 oz cans of R-134 and the compressor clutch engaged. A few minutes later and the low side gauge went into vacuum. So that's not a good thing. Indicates a clog on the lower pressure side so the compressor wasn't getting freon back to pressurize. So, it became obvious that crap got into the open system and it was time for a good spring cleaning. Ordered: Dryer (should always be replace when a system is opened to atmosphere), Expansion valve (the first thing that typically gets clogged as it's ports are very small), a compressor / clutch (just because they are relatively inexpensive and a high area of failure.

Parts came in and my buddy came over to lend a hand. Evacuated all freon. Opened up all fittings to all components. Removed the dryer, the expansion valve. Pushed AC flush solvent from a flush canister that is fed compressed air into all of the lines. White rag on the output side to trap any dirt. So, orange stuff came out (likely oil) but little dirt (that's a good thing. However inspection of the Expansion Valve shows the root problem. Dirt clogging the inlet...(see pic).

Dried out the hoses with dried compressed air. Attempted to install the new expansion valve and ...wrong part...so ordered the correct one now that I had the part number off (38901) the old one that was now in hand. Part arriving Friday. I will leave the system opened up to let the flush solvent evaporate and put it all back together Friday. To be continued...

 

[Rich W.]

Great information and good to know some people still fix things!

 

[DavidL]

All A/C parts installed (compressor, Dryer, Expansion valve, new ORings) and pulled a vacuum for a few hours and let it sit overnight with no sign of leakage. So, will turn Vac on for an hour today and recharge. Hopefully that will do it!

I did empty the oil out of the compressor to measure. 8 oz. I then replaced it with PAG46 that was in the system originally (same 8oz).

Put on Vac and an hour later, put 6 12 oz R-134 cans in. Pressures look good for 62F (25 Low / 155 High) but that's a bit cold to test AC. The good news is Low isn't negative (no more clogged Expansion valve). I will keep the gauges on for a bit and test once in a while. But tools are away, and the dash seems colder than ambient so we will call this one good for now!

 

[Rich W.]

All A/C parts installed (compressor, Dryer, Expansion valve, new ORings) and pulled a vacuum for a few hours and let it sit overnight with no sign of leakage. So, will turn Vac on for an hour today and recharge. Hopefully that will do it!

Put on Vac and an hour later, put 6 12 oz R-134 cans in. Pressures look good for 62F (25 Low / 155 High) but that's a bit cold to test AC. The good news is Low isn't negative (no more clogged Expansion valve). I will keep the gauges on for a bit and test once in a while. But tools are away, and the dash seems colder than ambient so we will call this one good for now!

at this point a thermometer stuck in a vent will tell the tale. Nice job! You're definitely a couple rungs above me on AC tools and skills.

 

[DavidL]

at this point a thermometer stuck in a vent will tell the tale. Nice job! You're definitely a couple rungs above me on AC tools and skills.

RV AC work isn't that hard. Much easier than auto as you can access all the parts easily. But exactly same tools and understanding as auto. Tools: yes, I have been doing this stuff a long time and always have my eye out for the tool that makes it easier. At some point I need to consider getting rid of stuff, but it seems the collection gets bigger, not smaller

Re: thermometer - more important is the ambient temp as that is what you use for what pressure settings apply for the time you are monitoring the system. If the pressures are good, then the dash temp will be what it is supposed to be.

The "only" thing the dash temp can see is if a hot water valve is stuck on, or if the system uses a blend air door (to mix cold and hot air to get mid temp) is stuck. But the freon side of the system is all monitored by gauges. An essential tool for a DIY'r to do ANY AC work. and relatively cheap (invaluable).