Sticking TXVS

[frostmonkey]

Hey Guys ran across an unusual situation today. Meat manager complained of several sections of his fresh meat cases warm. When I arrived at the store I found a total of 8 3 ft sections warm spread out through 16 cases ( Each case has 3 seperate coils). Checked subCooling at the inlet of the TXVS to find it at 15 Deg F,checked Superheat to find it at 25-30 Deg F. A small adjustment of the valve(1/8 to 1/4 turn open) would cause the valve to open and begin to feed. I'm thinking its caused by wax in the seat, mainly because there has been a history of pluged valves in this store since it was built 5 years ago. The rack that these cases are tied into is refurbished, so I suspect I will be experiencing this problem more in the upcomoing weeks. Anyone have any suggestions on how I can clean up this wax? And has anyone ever experienced waxing of this magnitude. This is a R-22 rack,with Zerol 200td oil.:confused:

[hvaccop]

Liquid line driers at TXV and strainers in the TXV

[cyro]

I have even put external stainers before the valve with a drier and a shut off.

[Dowadudda]

Oil changes on the rack. New Drier Cores. Pop out each TXV screen and clean with brake cleaner. That's just a start.

Why do you have the wax? High Discharge Temps?

[jat2020]

"Checked subCooling at the inlet of the TXVS to find it at 15 Deg F,"



i have never checked subcooling at the inlet of a txv is this a common practice for most of you guys, to make sure you got a full column of liquid? and is 15 deg f what temp your looking for? thxs for the replies

[Dowadudda]

what is the definition of subcooling? And why is a full column of liquid so important to the operation of a TXV.