A/C question - Steve Ebels

don_9

steve I forgot to mention that it also looks low on charge
I dont know what the temp or where you are at but here we at 90 so I am seeing around 75to85 low side 250 to 275 head
depending on what efficiency 25to30 split on outdoor coil and 15 to 20 at indoor coil. could have possible leak in ststem, sorry to say carrier known for leaking indoor coils.

Steve Ebels

A/C ???

Looked at an A/C system today and it didn't seem to be acting normally. 3 ton Carrier condenser with matching Carrier indoor coil. The split temp on the condenser was an avg of 17*. Suction pressure would run at 62#'s then gradually drop to about 54-55. Corresponding to this, the liquid line pressure would run at 185#'s then drop to about 165 when along with the suction. Both would then return to where they began and stay there for about 3-4 minutes before dropping again. When the pressure began to fall I noticed a sharp (6-8*) rise in the condenser split temperature which then returned to normal as the pressures came back up. HO indicated that the unit handled the load nicely last summer but can't seem to catch it's breath this year. Didn't find any leaks and both indoor and outdoor coils are clean. Amp draw was nominal. Am I looking at some non-condensable gas in the system?

BTW this is an orifice not a TXV system.

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don_9

ac

Steve it sure act like you have mositure in the system.
I would see if you can back charge in to condenser to make sure that the compressor is strong enough, IF it does go ahead in check the piston to make sure it the right one,
if all looks ok recover freon pull deep vaccum to about 500 microns, recharge unit also need to check superheat on piston system should be any where from 10to 15 degree for med temp system. door panel should have the factory chart
for superheat adjustment hope this help.

Dale

Sounds like a partial restriction

probably at the orifice inlet, I would also check for any house air bypassing the indoor coil. let us know what you find.

Steve Ebels

Ambient temp

Was 84* at time of test. Unit is on the East side of the house in the shade.

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don_9

T-P chart

Checking the temperature and pressure chart you should be
around 225 to 240 on the high side, check all above Its
definetly low on charge, I would ask if he ever had to add freon before, Sound to me carrier has yet to address the coil problem.

Wayco Wayne

Line temps

are needed to know whats going on. Both superheat and sub cooling are the window to what's going on. I like the suggestion tha says possible particles at orifice. Could be a clogged drier.

Greg Gurecki

If its a blockage Greg Gurecki

Steve if its a blockage you should notice a temp change near the blockage check the liquid lines temp near the oraifice if its cool there could be somethng in the orafice like solder or scale check the temps before and after the filter dryier and line dryer

Pat

AC

Pump the system down into the condenser(this will verify your compressor capacity. Open the orifice and make sure you don't have a bead of solder. Flush lines with nitrogen and and pressure test to check for famous leaking Carrier coils. Install a liquid line dryer, evacuate system, check the condenser for leaks with a Freon detector, refill the system with the freon in the condenser, run and check charge. (my guess is a non condensable gas - so you need the dryer and while the system is open check it out). Good Luck!

don_9

sorry

Mr Ebels
My son pointed out to me today at work that i gave you the wrong advice on my earlier post.To back the charge in to the condenser is a nono if it has a scroll compressor.That
scroll prohibit this Its has something to do with there no
resistance in a vaccum and that the winding in the motor will arch one to the other much like a set of eletrode in
oil burner.this some how burn the oil in the compressor.
I still pump down to about 20 psi and then recover the remainder. Old habit hard to break.Thanks Don jr and sorry mr ebels and to the wall also. don

GW

questions for the AC pros

I'm new at AC, always trying to pick up something new.
Dumb question #1- how can it be that the condenser has a leak? Wouldn't this be evident when you first charged the system- no r22 would be there??

What is the split at the outdoor unit? The indoor unit is supply air and return air, right?

If it's not a txv or an orifice, what else can it be? What are the basic ways to squirt the stuff into the evaporater? What is a piston, is this another type?

Thanks, Gary



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