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SharDonnay

Chassis A/C Blowing Warm Air

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We have a 2007 Fleetwood Revolution 40E that we bought used last December.

The chassis AC is blowing warm air.

I bought some R134a refrigerant to charge up the system. When I started adding, the system pressure (at the low side port) started to increase.....it had been zero when I started adding. The compressor clutch was not engaging at first, but as I added refrigerant, it started coming on.....for just a second or two every 30 seconds or so.

I continued adding refrigerant, and then the clutch stayed on (stopped cycling). The pressure was building, but then it fell to zero and won't come back up. The clutch continues to stay on. The vents on the dash are still blowing warm air.

I've added less than 2 lbs. of refrigerant.......Fleetwood says the total is 3.38 lbs.......so I don't think I've overcharged it.

The pressure on the refrigerant can gauge never got above the very bottom of the green zone.

Ideas???

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Sounds like it got a leak. Pull a vacuum with a pump and it should hold for more than 30 minutes. If leaking put some dye in it to find out where it comes out.

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SharDonnay,

Like Ray said. The system has a leak at some point.

You mentioned that the system started cooling and reached a point where the compressor stopped cycling. Then it stopped cooling and the amount of freon was less the required.

From your description of events, it sounds like the system is freezing up internally. This problem is caused by moisture that has entered the system.

You will need to use a vacuum pump on the system, during this process you will see steam forming at the pump exhaust.
This caused by the water bowling off under low pressure.

Watch the reading on the low side gauge of the manifold - this level will start to increase one you stop the vacuum pump.
Watch it for a good 30 min. to see it the gauge drops and how far the gauge swings to to "0" point. the rate of increase kind of tells you how big a leak is in the system.

You will then need to run the vacuum pump, close the proper valve on the manifold set - connect a can of freon with dye and continua to add freon until the system stops cycling - at this point you need to start to watch the High Side Pressure on the high side gauge of the manifold.

When you near the proper operating high pressure = keep an eye on the sight glass and watch for the liquid to be clear of bubbles.

You are now at or near the maximum high side pressure, stop adding freon (you should be close to required amount.
Let the system run for a time, then turn off the AC, let it set and with a black lite, look for a green glow - at some point in the system hoses, connection points, the condenser or evaporator.
And YES finding a leak in the evaporator can be very challenging. This is a point where you might need to call in some help to disassemble the heater and cooling section of the Assembly.

Work safe when working with freon and especially when under pressure. Do not inhale it or make contact with skin. freeze burn is possible !!!

This job does require the proper equipment and a good understanding of AC systems.

Rich.

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If you have experience with an automotive air conditioner continue on a DIY basis. Probably a leak as already been said. Once you find and correct the leak, you will need to add the correct amount of refrigerant, but you will also probably have to add refrigerant oil in the correct amount. Leaks usually diminish the oil and I remember reading that compressors 2007 and newer are prone to seizing up because of the lack of oil. When that happens you could lose an important belt. Perhaps a tow truck to a repair facility? A/C is usually not worked on the shoulder. You might save a lot of trouble and $$$$$ if you took your problem to a pro. My two cents.

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If you are using a quick charge kit with only one gauge on the can you need to get an ac manifold with high and low side gauges.

Quick charge kits are fine until there is something wrong.

No or low low side pressure but high side pressure for example,equals plugged or stuck expansion valve, blocked line, other problems.

Charge r134 by weight only not sight glass as many 134 systems will have some bubbles in glass when fully charged by weight.

Many small cans are only 12 ounce cans so charge by ounces not lbs.

dave

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I remember where I read about compressors seizing up. Perhaps a bad run in 2007 for a bit. It was on tiffinrvnet.com. A poster even mentioned that he had a second shorter serpentine belt that could bypass the compressor pulley and still power everything else. 40 feet away would one even hear it?

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Sorry it took a while, but I finally got this fixed. I needed a new compressor.....it was leaking refrigerant badly. The drier/filter was also plugged and was replaced. But the main problem was the compressor.

Thanks for the advice!

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