AC

[showcrop]

AC would have been nice mowing this morning. it keeps cutting out then won't come back on for 30-40 mins. If I try to add refrigerant when it is running like instructions say it pushes some back into can. If not running it will take just a little. Yes, I am on the low pressure side. any ideas?

 

[Anonymous-0]

Kinda hard to say whats going on without knowing what pressures you have ? System may be over charged?

 

[cadet trooper]

There can be a lot of reasons i.e. plugged cab filter, low pressure cutout, moisture in the system blah, blah and blah was anything done to the system like a compressor change or any major component change? All info would be helpful to most on here I'm not an A/C specialist but I'm sure someone on here can help with a complete background of the system.

 

[showcrop]

I have just replaced the compressor, the system takes 6 cans total and I did loose a lot and I have put in only about 2 cans Is it possible to overcharge with the little 16 oz cans?

 

[mEl]

you said that you replaced the compressor, did you also change the reciever drier, did you have a vacuum pump pull the system down to a deep vacuum and hold it there for an extendede period to assure that all the moisture was removed, if there is moisture in the system it will freeze the expansion valve or orfice tube, however the system is equipped. As the other gent said, you need gages attached to the system to properly diagnose it, and the knowledge to know what they are telling you.

 

[bradk]

I totally agree with Bryan in Iowa.Alot can be told with both pressure guages on the tractor.

Until then,it's anybody's guess.Bad txv,orifice valve,over/under charged,oil logged,etc.

Did you evacuate sytem to deep vacuum(35hg) before charging? Won't ever cool very well unless it's done.

 

[Cummins 1955]

Did you get suction and pressure lines reversed? Identical compressors can have different porting.

 

[Brian Jasper co. Ia]

You did evacuate the system before charging right? Are you charging an R-12 system? It wasn't until the later years of R-12 that they changed the high side fitting so people who didn't know much about A/C would be unable to connect to the high side and explode the can. Original 134A systems are fool proof on their connections. If it's trying to pressurize the can you're on the high side. It's impossible to pressurize the can on the low side.
1. You need a manifold gauge to see what's going on. No way around it.
2. You need a vacuum pump to remove the air and moisture that enter the system with lines disconnected. No way around it.
3. When charging from small cans always purge your can tap hose each time before you connect it to your gauge. Air mixed in the refrigerant dilutes it and causes higher than normal pressures with reduced cooling performance. If the low side port is right on the compressor NEVER turn the can of refrigerant upside down to get liquid to charge faster. Liquid refrigerant entering the compressor can cause valve failure or a twisted off shaft.
4. Why did you replace the compressor? Just leaking or catastrophic failure? Did you check the expansion valve for debris? If it shredded itself, you need to flush the system or you'll destroy that new compressor and plug your expansion device.
5. When opening an A/C system you should always replace the dessicant. Some are receiver/dryers on the high side between the condenser and expansion valve. Others are accumulators on the low side between the evaporator and compressor.
6. You need lots of fan through the condenser. If the engine fan clutch is tired, you won't have enough heat removed from the refrigerant and have too much high side pressure with poor performance.
7. You need a leak detector to find small leaks. Soap solutions can find large leaks. Tracer dye and a black light work well for small leaks.
8. If you need more help, feel free to email me. I'm the primary A/C tech in the shop I work for.