Depending on the load you either have an undersized evap or over sized c/u. That is a 3000 btu evap with a 8000 btu (w/30° evap @ 90° ambient) c/u that was never designed to operate in the temperature range for wine storage.
You want your system to have about a 10° TD @ 45° SST.
Currently your coil is way to cold and if it isn't creating a dry environment it's only because of the short run times due to over sizing.
What is the size of the room and what kind of insulation is there? What size is the TXV?
There is absolutely no reason for a defrost cycle.
Perhaps an EPR may solve your issues but if the client has a valuable collection I'd rip it out and start from scratch.
A wifi enabled tstat should be an easy up sell on this job.
My WAG is the system has always had high head pressure and that's why the first c/u only made 5 years.
All good points...especially the undersized evap and possibly oversizing (and misapplication) of the condensing unit.
The problem I see here is this customer appears to be happy with his system, so it's going to be a tough sell for a complete redo after only a bad fan motor.
I appreciate all the replies. well I cant say this guy is cheap he did give me a 40 dollar tip after replacing the evap fan motor. once I went back our company did not charge for me to go back and recheck everything he said he is willing to pay again. is rare he wanted to tip again but I told him no I cant take it because I don't feel comfortable taking the money when its not operating properly, its for his collection, he collects wine pretty big collection he tells me he has 4,000 bottles that's crazy, it doesn't look that big but they are crammed in there. one thing that some one posted could also play a big role he is adding more bottles overtime increasing the load, he would probably purchase a new unit if it was the ultimate fix. from what I know sizing the cellar is tight since your dealing with humidity and temp control. ive installed a big wine cellar but someone else sized it up so I did the easy part. I don't feel our shop is sharp enough on the refrigeration side to really size it correctly, based on a few previous job discussion but im no expert myself, but im always up for knowledge . so once we replace it we have a new issue and its my face that's going to be seen everytime. as far as the drain line loosing its prime the evap coil is a forced air style. so it doesn't pull the air up the drain line. my split across the evap coil is 12 degrees. seems a bit high
The key to any walk in wine cooler is the construction as a wine cooler. Without a proper vapor barrier problems, repairs, replacement and maintenance is going to be high.
If you walk in does not have a proper vapor barrier, insulation and seals around the openings such as doors you will be fighting an uphill battle all the time especially during season changes if the wine cooler is subject to an unconditioned space.
The proper refrigeration system, hand built and sized properly, is the next step in keeping to a good running system for temperature and humidity control.
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