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Discussion Starter #1
I had my compressor replaced on an older unit last June. Doesn't appear to me to be cooling as well as it did last year. I installed a thermometer in a main vent and it usually will blow anywhere from 60F on down to the mid to low 50's. I understand it should blow around 45F or even lower.

My colleague who happens to be HVAC says he will give me a can of R-22 and the hose to introduce it into the system. He does cars mainly but also handles his own home's AC system.

Just hold your hand on the cold line until it gets really really cold... Then you're done. But, he also said don't over fill it! With a dire warning...

Suggestions?
 

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Discussion Starter #3
By subcooling you mean I should run it full-blast for 15 min or so? Then turn off (breaker-switch) connect and charge?
 

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If you overfill the system the liquid refrigerant can flow back to the compressor causing damage. Get some gauges, and charge to superheat/subcool numbers and check the manufacturers procedures to optimize your performance.
 

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You should get a contrator to see if its low on charge before you damage your compressor.

If you don't have guages, and temp probes for line temps. Your really risking damaging your A/C.

Your friend. Is telling you the worst ay there is to add refrigerant to a system.

Also. Your system should not always blow 45°F air out the vent.

Your system. Risk it as much as you want.
 

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Discussion Starter #6
Yes, I'm very nervous about damaging such an expensive and vital part of my home! I may just call my AC company for a check-up instead.

This has been very good advice.

beenthere... so it is normal to have such a fluctuation in temps blowing out the ducts? I was thinking the coils might be dirty too. They haven't been checked since I bought the house a 17 months ago.
 

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Dirty coils do change the temp out of the vents.
How humid it is in your house changes the temp out of the vents.
How hot it is outside changes the temp out of the vents.
How clean or dirty your air filter is does too.

Plus, if you had a contractor do the compressor swap out. And the leak is at one of his braze joints. He should fix it for free.

If its at the indoor coil, or some other place. You may want to consider having it fixed, depending how bad its leaking.
 

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PURGING the hose is the biggest concern there...if you want to do it the system has to be running stat all the way down 50F.hook the hose up to the service fitting going into the condenser on the suction insulated line.hook the other end up to the tank but not tight open the service valve and let it bleed then tighten it ...keep the can in the upright position for GAS only.crank the service valve 2 CW turns to open the suction(not all the way CW it will shut the line off)you have the tank hooked up,purged..open the valve all the way on the tank....feel that suction and when it goes ice cold shut the TANK only.go inside and see what the split is on the evaporator section return air vs discharge air as the unit gets charged your split should widen your looking for 18F to 20F difference.let it settle and check the split 15 minutes if it did get coler on the air into the space repeat the outside again....chill that suction and shut the tank redo the temps.the temperature readings are at the filter rack RETURN then the duct on top of the furnace for the supply..follow that PURGING step it is critical when charging:eek: if you don't do it you will introduce hose air into the system.don't get too use to doing this because with the freon leak your loosing oil DROPLETS with the leak and the compressor is lubed by it...lockup or burnout might be in the future major $$$$$$$$$
 

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subcooling/superheat

Go buy a cheap temperature probe. Look up sub cooling or superheat on the net and check charge. OH! Ask your buddy for both hoses and gages and hook them both up. Be real careful of the small line it's very high pressure and it will burn you if you don't take it off fast or without gloves.

Now the real recommended procedure call a HVAC mechanic, you might not even be low on freon it might be something else.
 

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I had my compressor replaced on an older unit last June. Doesn't appear to me to be cooling as well as it did last year. I installed a thermometer in a main vent and it usually will blow anywhere from 60F on down to the mid to low 50's. I understand it should blow around 45F or even lower.
Depends on the room temperature. Been 10 years since I was doing field work but only expected about a 10 degree drop in temp at the vent.

My colleague who happens to be HVAC says he will give me a can of R-22 and the hose to introduce it into the system. He does cars mainly but also handles his own home's AC system.

Just hold your hand on the cold line until it gets really really cold... Then you're done. But, he also said don't over fill it! With a dire warning...

Suggestions?
Bad advice!

Get a professional to check your system. There are many possible reasons for air temp to vary. Could just be dirty filter or evaporator coil or...
You may not even have a problem.
 

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Discussion Starter #11
I made an appointment with the company that replaced my compressor last Summer. It'll run me $80 for the A/C or $125 to include a return in the fall for the furnace.

I think it'll be a pass on the furnace since I turned on the heat only a couple times last Winter- if that is what it could be called. Don't think it ever got much below 60 inside and I think 64F is the "sweet-spot" in cold months.
 

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Discussion Starter #12
The A/C guy just left... Everything's functioning properly. No need for extra refrigerant. I'm glad I didn't try to DIY this...

I may just take some HVAC courses at a local CC so I can do minor check-ups and buy refrigerant if I get licensed. Then I'll know more too.

Thanks guys. I could have made a real mistake!

rad
 

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ha ha ha rotfl almost fell out of my chair,so the biggest concern is purgeing????? hardy har har thanks for the entertainment
PURGING the hose is the biggest concern there...if you want to do it the system has to be running stat all the way down 50F.hook the hose up to the service fitting going into the condenser on the suction insulated line.hook the other end up to the tank but not tight open the service valve and let it bleed then tighten it ...keep the can in the upright position for GAS only.crank the service valve 2 CW turns to open the suction(not all the way CW it will shut the line off)you have the tank hooked up,purged..open the valve all the way on the tank....feel that suction and when it goes ice cold shut the TANK only.go inside and see what the split is on the evaporator section return air vs discharge air as the unit gets charged your split should widen your looking for 18F to 20F difference.let it settle and check the split 15 minutes if it did get coler on the air into the space repeat the outside again....chill that suction and shut the tank redo the temps.the temperature readings are at the filter rack RETURN then the duct on top of the furnace for the supply..follow that PURGING step it is critical when charging:eek: if you don't do it you will introduce hose air into the system.don't get too use to doing this because with the freon leak your loosing oil DROPLETS with the leak and the compressor is lubed by it...lockup or burnout might be in the future major $$$$$$$$$
 

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Nice post

ha ha ha rotfl almost fell out of my chair,so the biggest concern is purgeing????? hardy har har thanks for the entertainment
KENNZZ05, I loved your post it cracked me up . I wouldn't let biggles on my property with a truck that looks like his. :laughing::laughing::laughing::laughing::laughing::laughing::laughing::laughing::laughing::laughing:
 
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