Weak air conditioning

[sardillim]

uUnfortunately I think this is one of those situations where you need to know how much refrigerant is in the system and the only way to do that accurately is to evacuate the system with a machine so it can weigh the amount of refrigerant recovered I'm gonna assume you do not have a machine to do this. So my suggestion would be To completely discharge the system (safely) And recharge it You could get most of what you need to do this from Harbor Freight All you really need is a scale the refrigerant a set of gages and a vacuum pump my suggestion don't skimp on sucking the system down with the vacuum pump let it run for a while make sure you get everything out Then look up from Kubota the amount of refrigerant it calls for do not add any more do not add any less put the exact amount in overcharging is just as bad as undercharging the system and don't forget to add oil and I think you'll be fine

 

[Tx Jim]

Try adding a 12 oz can of R134A to the system (without the "sealer" ) and see if it makes a difference. If it does, then you can decide if you want to add more or just evacuate and refill. To do the job correctly, you need to know how much is in the system, just like you did with the R12 and only fill to the specification. Sometimes you don't have the luxury of doing it this way, so adding some slowly might be the best that you can do. On the R12 systems, you had the sight glass to assist in getting the charge close.

No way I will add refrigerant without monitoring both high & low gauges. A little too much refrigerant causes poor cooling similar to not enough refrigerant.

 

[chim]

A friend of mine is certified and has an HVAC business. I've seen him work and he has coached me through a few problems. He goes by what his gauges read with the ambient temperature and I doubt he ever pumped a system down as a starting point.

 

[jaxs]

A friend of mine is certified and has an HVAC business. I've seen him work and he has coached me through a few problems. He goes by what his gauges read with the ambient temperature and I doubt he ever pumped a system down as a starting point.

Your friend is doing by science and theory of refrigeration, not what he saw on utube or heard on some tractor forum. It's called superheat and subcooling when taught in trade school.

 

[lawnmower]

Update: I instaled the expansion valve and dryer then vacuumed and charged, the problem still there. I then ordered a compressor and another dryer, when they arived I removed the compressor and drained the oil out if it into a glass measureing cup. The oil was not clear it had a black tint to it. The new compressor instructions said the oil must be clear or the system needs to be flushed. I then ordered a flushing kit on line and got a gal. of flushing solvent from Autozone. I took the lines lose from the expansion valve, dryer and compressor, then flushed from the top down. I then added oil as per shop manual amounts to evaprator, condensor, dryer and new compressor. I vacuumed for 1 hr. then charged. This solved the problem. At 1500 RPM and 75 deg. F the low side reads 25 psi. and High side is 185psi. The vent temp at 1500 RPM is 46 deg. F PROBLEM SOLVED

 

[chim]

Update: I instaled the expansion valve and dryer then vacuumed and charged, the problem still there. I then ordered a compressor and another dryer, when they arived I removed the compressor and drained the oil out if it into a glass measureing cup. The oil was not clear it had a black tint to it. The new compressor instructions said the oil must be clear or the system needs to be flushed. I then ordered a flushing kit on line and got a gal. of flushing solvent from Autozone. I took the lines lose from the expansion valve, dryer and compressor, then flushed from the top down. I then added oil as per shop manual amounts to evaprator, condensor, dryer and new compressor. I vacuumed for 1 hr. then charged. This solved the problem. At 1500 RPM and 75 deg. F the low side reads 25 psi. and High side is 185psi. The vent temp at 1500 RPM is 46 deg. F PROBLEM SOLVED

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