What happens if you convert an R410A system to R22?

[man from trane]

My senior tech called it a "horror show" in the back of this little supermarket.

I opened up a newer Lennox Signature XC21 5 Ton condensing unit to see why the compressor wouldn't start. Someone had put a hard start on the run cap and the hard start was fried. The run cap was good but compressor still locked so I replaced the hard start. Started fine then and pulled 24.5 amps.

Liquid line felt hot, found the fan upside down (cupped downward, blowing upward). Re-installed it correctly. Seemed to run much better but I put my gauges on just to check. 190/80. Suction temp at compressor was 48 Deg F. Wtf. All data says R-410A. I recovered some gas and got the superheat up to about 5 Deg, just enough that the compressor stopped sweating. I would have recovered more but was taking out a lot of oil with the gas. The amps came down to 18. Better.

What do you figure the hacknician who got thrown off the job did? Nothing is off limits for this guy. He had a 2 HP reach-in cooler running for months on dual evaps with no orifices or TXVs installed. Orifices still in the bag next to where he sweated in the liquid lines. He was using the liquid service valve as the expansion device!!

Anyway, do you suppose maybe the AHU still has the R410A TXV in it and that is why the SH is low? If it is a 410 TXV it's going to stay open. Evap is running about 43 Deg now so that's not bad. I'm just baffled as to what the heck this Frankenlennox is. I did not look at the AHu yet. Might not even be a Lennox.

BTW, ambient was 82 F so I know it's not just R410A with a severe undercharge. No way it could be only 190 head pressure with a 48F suction temp.

[DavyB]

This is a job for PHM.

[Shophound]

Are you saying someone converted an R410a split system Lennox to R22? Or you think they might have...or did it half-*ss, i.e. part 22, part 410A, and you're wondering which way you need to go to get it working correctly?

I'd start by looking at the nameplate on the condensing unit, and, if possible, the data for the coil in the air handler. Look at the data on the compressor as well and then look it up. You need to figure out what the thing is SUPPOSED to be, and then make decisions based on that. If it is completely FUBAR Frankenmonster and can only be corrected by swapping out with the correct components, then you can advise the customer likewise.

[man from trane]

Got the story from the owner today. Three year old compressor died so the hacknician replaced it with one from his spare parts that was R-22 and he did not change the TXV. It's a ZRD49 so at least it's Ultratech. Second stage doesn't change anything when it calls so the solenoid might be shot. It actually kept the store cool today without using the other AC so that's an improvement. What a cluster!