Topic: R22 dry units are all gone...

...what are you all doing as far as replacement refrigerants like R424A? At roughly $5-7K per complete system, how are you handling replacements when compressors die or coils cannot be repaired? We've blown thru 3 condenser change outs in 2 days, along with a coil box. My guys are holding up, but options are quickly running out.

BTW...yes, long ago I knew this was coming down the pipe, in fact, I did everything I could to be out of apartments by now yet, here I am. Like Michael Corleone in "The Godfather III", I can only say, "Every time I think I'm out of it...they pull me right back in!" Where I work now simply has no means for this kind of thing, and the turnover rate for techs in the past rivaled McDs.

Robert, we have used 424A with success. Just make sure all 22 is out of system first. Pressures are about the same. We have noticed that on very hot days it does not seem to cool as well as R-22.

Any thoughts on M099 or R422? They seem to be more easily recognized in my area...

A complete change out. Or just the coil and condenser then flush the line out still time consuming

I would go with the M099. No oils change and it works well. Remove 22 and install M099. Works at a slightly lower pressure too.

With the Dry 22 units off the table, we still have the option to replace the compressor only. Some things to pay attention to:

-If the new compressor is pre-charged with Poly-ol-Ester (POE) oil, you can recharge with R-407C (Flush the line-set and coil, check the metering device). This refrigerant is considered to have the closest capacity (+/- 1% difference)of all the retrofits compatible with R-22 equipment.

-All retrofit refrigerants (refrigerants other than R-22 that will work in an R-22 system) decrease capacity. All retrofit's require removal of the existing R-22 before charging with the retrofit... DO NOT MIX REFRIGERANTS!!! Verify Oil compatibility as well.

-Be aware of your supplier. If someone comes along with a "New and improved, must buy right now, deep discounted price, short time only" refrigerant that solves all the problems... Buyer beware. Verify refrigerant with the EPA SNAP listing www.epa.gov/significant-new-alternatives-policy-snap to ensure it is legal.

-Proper use of HFC retrofit refrigerant is the same as the procedures with R-22; with one exception: All current HFC refrigerants are blends, requiring the refrigerant to leave the jug as a liquid. As the refrigerant should be a gas before it gets to the compressor a charging adapter is recommended. If the compressor sound changes when charging, the technician is allowing liquid to get to the compressor; this is bad and will shorten the life of the compressor. (especially if the compressor is a reciprocating type.

Paul. I have a question that you might can help with. I have a friend that is a maintenance supervisor at the apartments I live at. He replaced an outside R-22 unit with a 410A. He said the airhandler was alseady rated for 410A so no need to change. The problem is it is running all day at 90+ outside temp and not freezing up. As soon as the sun drops it freezes inside and out. I put my SMAN 360 gauges on the unit and it read 124.5 low side pressure, 411.1 high side. The wet bulb inside was 64 with outside temp of 91 which gave me a Target SuperHeat of 8.7. So I now have my target superheat of 8.7 and actual superheat of 43.2 indication low on freon. At this point we start installing freon and before we have 1 pound in the compressor starts loading up. The low side goes to 144 and the high side to 465. The super heat never came below 38.7. I asked him if he was sure he changed the expansion valve ( not a TRX ) and he said he did change it out with the one that came with the compressor. Any thought on the direction we need to go with this?

Shot in the dark since we aren't at the system. If you mean by saying that the "compressor is loading up" that the sound of operation has a drastic change, that could indicate a restriction in the line.

When the new condensing unit was installed, was the lineset correctly sized for the distance? if not, then the lineset is acting like a metering device and throttling down the refrigerant causing the compressor to have to fight too hard to move any additional refrigerant that is added.

Another possibility is moisture in the system. Did your friend pull a 250 micron vacuum, and hold it below 1000 microns? If there is moisture in the system, it can give the symptoms you describe. Due to the extreme affinity that POE oil has for moisture, even if he pulled this deep a vacuum, it is possible that the filter drier is full and clogged, providing a partial restriction as well. Check the temp before and after the filter dryer when the system is operating. A 5 Deg or greater difference indicates the dryer needs replacement. For best results the liquid line filter dryer should be installed right before the metering device inside the apartment.

These are the two areas I'd investigate....

Paul. I just found out that he did not change out the air handler unit. It is only rated for an R22 system. Would that cause what seems to be a restriction problem?

According to Goodman, if the evap coil was made after 1992 and he changed the metering device to match refrigerant and system size, he should be OK.

Based upon all of the information you have shared, and he for sure flushed the line and coil as directed to remove the mineral oil and brazing debris before installing R-410A as well as removed all moisture before charging the last guess I have from this distance is that the metering device is either clogged or stuck.

To repair that issue he'll need to recover the refrigerant, open it up and verify both it and any screen present is clear of debris. It would be a good idea to install a filter dryer 6" from the metering device after blowing the lineset with at least nitrogen as well. (be sure there is only one filter dryer per side.)

If you would prefer to discuss this more directly, feel free to message me through my profile.

Hope this helps...

Paul