Walk in Freezer

[vzenuh]

Here is another of my adventures of the week. I get the call that a walk in freezer is not functioning properly. I arrive onsite and speak with the manager to find some history on the unit. He informs me that they have been having problems with said unit for quite sometime and that their "corporate" maintenance man had said that the compressor is prob shot and needs to be replaced.

The box is at ambient and I grab my ladder and hop up on top. Condensor fan motors are running but compressor isn't. I check voltage on both sides of the contactor and at the compressor terminals. Voltage is fine. I kill power to the unit and find that the compressor has open windings. Cool the compressor down and ohm it out and it ohms out correctly. Restore power to the unit and it fires right up. Pressures seem fine. As I wait for the the coil to cool down so the fans come on, I notice that after five mins that they are still off. Pop the cover off and see that the fan cycle switch is just hangin there not attached to anything. Fix that and notice that I have about 80 degrees of superheat at the sensor bulb, remove bulb and hold in hand to see if any change, none. Need to replace TXV.

Return the next day with new parts and proceed to recover the refrigerant. I weigh the jug before and after and see that I have recovered 14 lbs of 404. Hmmmm,,,,change out filter dryer and txv and evacuate system. I then start weighing in my charge. It only takes me 8 lbs.

I am guessing that their maintance man is thinking like he is working on a residental unit. If the suction is low,, just add more freon. If their wan't an accumulator in the system he would have taken out that compressor a long time ago.

Once I find my memory card I need to upload some pics to the wall of shame for two other units that I found onsite.

[trippintl0]

The sad thing is, the compressor probably has sustained damage from repeatedly tripping internal overload and will likely fail a few weeks after your repair, and maintenance man will say, "SEE, I TOLD YA!"

[basprofessional]

That's typical corporate america paying the lowest wage they can for refrigeration mechanics.And Corporate america is getting exactly what they pay for. I guess it's called job security...

[vzenuh]

The sad thing is, the compressor probably has sustained damage from repeatedly tripping internal overload and will likely fail a few weeks after your repair, and maintenance man will say, "SEE, I TOLD YA!"

This isn't the first time I have delt with this fast food chain in our area. From what I heard from the other techs that I work with, is that "he" will attempt repairs, and usually when things don't get his way, we get called.

He does all their HVAC work, it seems that once he gets into refrigeration is where his shortcomings are.

Is there a possibility that that compressor may crap out in a month or two? Possible. But I know that when I left, I did the best possible job that I could.

The biggest problems that I have found going behind the maintance man is, loose txv sensing bulbs, and improperly adjusted txv's.