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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.

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

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.

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.

If the customer has had some type of change of use as in overloading the wine cooler or the insulation anywhere in the walls or at the gaskets for the door(s) create humidity infiltration then you can get a frozen coil even if the refrig unit is working correctly.

I also put in a 8 to 10 degree differential on the controlling thermostat to allow the coil to defrost. And, at times, I will wire the fans to run all the time for a much better defrost. The coil itself can get gummy and hold on to the condensate. Or the drain line may have lost it's prime and is sucking humid air back through the coil and that will definately freeze a coil.

All things to check but make sure the unit is cycling off on temperature and not short cycling.

No corrections factors were used for what I posted. I only came up with a quick estimate of how the condensing unit and coil you have "should" balance out for a 56ºF box.

If you were to take into consideration your measured evap temp of 25ºF, then the TD would be 56 - 25....or 31ºF TD. This "could" be due to a high evaporator superheat, or possibly a significant pressure drop in the suction line...since I assume your suction pressure was taken at the compressor and not at the coil.

Also, I've found that many commercial evaporators don't perform up to specs in the real world. I was told by a factory engineer many years ago that these coils, unlike A/C coils, are not AHRI tested and rated, so the manufacturers fudge the number a bit...up to 35% or so. It's called "commercialized" ratings.

Originally Posted by icemeister

If the replacement motor isn't dimensionally the same as the OEM motor so the fan blade isn't in the correct position, the airflow will be affected significantly. I suggest getting the proper OEM replacement from Heatcraft. A low airflow will tend to cause loss of capacity and the coil will run colder than design.

I assume you're talking about a GE cast iron unit bearing motor. They usually go from a 9 watt size to 16 watt....I've never seen a 14 watt.

Look up the capacities of the condensing unit and the evaporator and you'll find they balance out at about 6500 Btuh with a rather large 22ºF TD. This means that if all is to specs, with a 56ºF box temp, your evap temp should be 56-22 = 34ºF...or above freezing. (Your stated suction pressure of 22 psig corresponds to a 20ºF evap temp.) This is a medium temperature condensing unit with an operating envelope which tops out at 25ºF SST. It really should have been a high temp unit for this application.

Also, the Copeland specs for the FTAM-A075-IAA R134A condensing unit shows a compressor RLA = 11.8 Amps and at 90ºF ambient and 25ºF Evap temp the condensing temperature should be about 122ºF or around 175-180 psig.

If it freezes again I'll have to order the original evap fan motor. I'm sure it was a 14 watt no one stocked it so I had to to with the 16 watt. That could be my issue. Even though to me it feels like the same air across both fans but that's the answer I'm looking for so I side more with that. also almost and reality are two different things. But my 22 Psig corresponds to 25 degrees. On my pt chart. you've stated a lot of useful info as usual, maybe the numbers got crossed or u calculated in some correction factor your capable in doing that. Either way I'm stil off by 10 degrees td! So my input didnt make a difference thanks for the info

If the replacement motor isn't dimensionally the same as the OEM motor so the fan blade isn't in the correct position, the airflow will be affected significantly. I suggest getting the proper OEM replacement from Heatcraft. A low airflow will tend to cause loss of capacity and the coil will run colder than design.

I assume you're talking about a GE cast iron unit bearing motor. They usually go from a 9 watt size to 16 watt....I've never seen a 14 watt.

Look up the capacities of the condensing unit and the evaporator and you'll find they balance out at about 6500 Btuh with a rather large 22ºF TD. This means that if all is to specs, with a 56ºF box temp, your evap temp should be 56-22 = 34ºF...or above freezing. (Your stated suction pressure of 22 psig corresponds to a 20ºF evap temp.) This is a medium temperature condensing unit with an operating envelope which tops out at 25ºF SST. It really should have been a high temp unit for this application.

Also, the Copeland specs for the FTAM-A075-IAA R134A condensing unit shows a compressor RLA = 11.8 Amps and at 90ºF ambient and 25ºF Evap temp the condensing temperature should be about 122ºF or around 175-180 psig.

Originally Posted by carmon

195 is to hi..... what controls the compressor.....hopefully temperature control

it's a pump down system. And of course a low pressure control in the condenser shutting down the compressor. It has an external thermal overload to protect it. Wasn't sure what your question was reffering too

Originally Posted by EEAllen

the high pressure is okay if it's hot, well it's hot at miami. Your thermostat is set to 56 degree, it shouldn't frost at all imo. Check your thermostat, see if it's working properly, check the position of it. Best bet is thermostat failure.

It's an electronic thermostat Johnson control a419, I Was playing with it testing it. Seems to work properly. It had a feature that if it had an issue with the sensor you can allow the unit to continue to run. It was set at that so maybe intermittently its screwing up so I changed the setting to if it has an issue it shuts down the unit!! So if he was to call now and say his cellar is hot then sounds like the thermostat is acting up so I'll have to wait and see

the high pressure is okay if it's hot, well it's hot at miami. Your thermostat is set to 56 degree, it shouldn't frost at all imo. Check your thermostat, see if it's working properly, check the position of it. Best bet is thermostat failure.

195 is to hi..... what controls the compressor.....hopefully temperature control

Originally Posted by trippintl0

195# head seems high, unless it was really hot that day... Make sure condenser is clean!

Superheat 27 degrees, at compressor or evap? If that's compressor superheat then that's perfect. But if thats evap superheat then way too high. Don't choke the TXV to control amp draw. Use a CPR valve for that if necessary. Set the TXV for proper evaporator superheat (10*).

Yep it's compressor superheat sorry I don't add that part I try to give as much as possible thanks

Originally Posted by ECtofix

Two things come to mind from what you said:
1. Evaporator fan shroud should bisect the blade depth. Easiest way is is to line the blade's hub up with the shroud. If not done properly, airflow isn't right.
2. TXV setting should be desired superheat at desired temp setpoint. So...superheat is way off for 55 degrees.

That's my two cents. I've never worked on a W/I wine cooler. Somebody here will certainly give you more feedback.

Thanks for the input about the fan blade position I believe I understand what u mean! Basically the center flat area should be even with the shroud pretty much 1/2 the blade will be on one side and 1/2 on the other???? Hopefully I'm explaining it smooth

195# head seems high, unless it was really hot that day... Make sure condenser is clean!

Superheat 27 degrees, at compressor or evap? If that's compressor superheat then that's perfect. But if thats evap superheat then way too high. Don't choke the TXV to control amp draw. Use a CPR valve for that if necessary. Set the TXV for proper evaporator superheat (10*).

Two things come to mind from what you said:
1. Evaporator fan shroud should bisect the blade depth. Easiest way is is to line the blade's hub up with the shroud. If not done properly, airflow isn't right.
2. TXV setting should be desired superheat at desired temp setpoint. So...superheat is way off for 55 degrees.

That's my two cents. I've never worked on a W/I wine cooler. Somebody here will certainly give you more feedback.

walk in wine cooler

this walk in wine cooler the evap section has been in place for about 10 years and the condenser was replaced about 5 years ago. according to the home owner pretty nice guy. last time our company serviced his wine cellar was about 1.5 years ago. I went like mid last week found evap coil frozen unit has 2 evap fans the left one was bad. hmmm pretty straight forward bad fan motor, the original motor was 14 watt suppliers only stock 16 watt so I used that. its the little black motor usually seen in condensers. its about 1/2 inch fatter so the blade sticks through the shroud about 1/2 or less than originally I don't think it makes much of a difference because the cutting edge of the scoop stick out more in turn will scoop more air, the higher end of the blade where the air flies off still sticks up through the shroud so it is moving the air. now about 5 days later on the weekend on call guy gets aa call unit is frozen. he doesn't do refrigeration he defrost it and fired it back up it was Saturday I went back today Monday unit was at 53 degrees and not frozen it was off on temp. evap. heat craft m#c30af s# d01j07619 condenser Copeland m# fatm-a075-1av-020
s# 11a10608u r134a sight glass at the condenser is clear 22low/195 hi psig unit has a receiver I forgot my subcool. superheat was 27 degrees. nameplate specs comp rls 6.9 actually I was drawing 7.5amps so even if I opened my txv my amps will climb higher. box temp was 55 degrees. 27 degrees superheat I feel is good because basically this is a cooler setup just operating at a higher temp. thermostat is set at 56 degrees cut in cut out was 53 degrees. im worried its going to freeze again. looking for some input