Can True GDM-10 soft drink coolers that operate at 33-42 degrees have a replacement temp stat control that would make them run at 55 degrees to sell collectable red wine . This, True GDM-10 operating temps, can they be changed to run at 55 degrees

[olivero]

As a server of the cold and hot side of life, The compressor might also just operate like it always has when it was originally SET UP to run it below 45* which is what the thermal expansion valves and the refrigerant charge, and type of refrigerant was put in for, it will be for specific temperatures and the TXV along with superheat will be calibrated for it to be bringing it that low.

 

Now you raise it by another 10-15 degrees and throw your superheat way out of whack for the original purpose, now your gas is coming back hotter than it was (increase in superheat) and you will lose effeciency but then again, it will probably run just fine, not as efficient but really should not do any major damage.

 

Seems to me like the worst that will happen is that it will be ineffecient in terms of operation which I guess does not matter since you want it higher than the original setting anyways…

[alnelson]

I don’t think running a gdm at 55 degrees will kill a compressor within a year or two.

[olivero]

It won’t there is no reason for it.

 

The only thing that will change is its performance which is insignificant because it is wanted that it keeps a higher temp than what it is designed for. It should not hurt anything.

[fixbear]

al contraire my friend. If you take a ammeter and check the compressor at start-up with a hot box, you will notice that it is in a overload condition for some time before the system settles down and the amps drop to full load rating and then down to a much lower load as the box reaches the bottom of the cycle. If in it’s designed temp. Now the thermal  protection doesn’t trip in this circumstance because the compressor is cold and there is no residual heat. As well as a thermal time lag to the case.

Once running the system is hot and the restart under the high load starts a short cycle situation if the box is kept at a high temp. You also will lose suction line cooling for the compressor allowing even more heat build-up in the compressor. How long does a compressor last if the condenser  is plugged? Or the fan is not running to speed? Basically the same end result.

     If I’m wrong on this thinking, tell me why.

[fixbear]

This is a Cap tube system. they require a much closer operating design than a TXV does. With a TXV we could tweak if to run without killing the unit. (bypass TXV and charge design)

[olivero]

Well, what you are saying is not wrong but think of it in a way of load.

 

The compressor only has to run until it reaches the set point, the superheat increases in the suction line and reduces the amount of cooling the compressor gets, true. But the supply air coming off the evaporator coil will be maybe 32-35 degrees currently if the superheat is correct.

 

That puts your delta D at 20 degrees and as I am sure you know, the larger the DT the faster it goes so the compressor will not have to work as much and definetley not for as long as it currently does. I doubt the compressor will even get very warm bringing the temp down from (if it was my case) 75 degrees to 55.

 

If it’s bringing down the temp to 35 or 36 degrees like normal fridges, the less heat is in the box, the longer it takes to get it out and the longer its on for. Its like scraping the bottom of the barrel compared to bucketing out of the barrel.

 

I really don’t see an issue with it. But then again, I am just guessing based off of what I know, if you really want to make sure, you would check the temp of the compressor now when its on. and after you put in your thermometer.

 

Having the super heat all out of whack by making it operate in a higher temp will cause you inefficiency, that inefficiency could cause it to run for longer as your refrigerant might just turn into gas very early in the evaporator which will slow down the cooling but without knowing  what your pressures are, I can’t do much but guess. IT could also be just fine but 100% certain that you will lose efficiency, just not sure how much, your air coming off the evaporator will be warmer but the system should be able to cope with it.

 

IF you can tell me what the pressures are supposed to be on the high and low side, I might be able to get a better idea of how much. This thing uses HC-290 refrigerant (propane interesting.

[fixbear]

I think that we have forgotten about the use of the latent heat of solidification. and how we use it in a cooler. Buy taking the coil down to 17 to 19 degrees we create a form of heat storage to lengthen the cycles out and increase efficiency. Remember how many BTU’s it takes to freeze or thaw a pound of ice vs. a pound of water. All 32 to 40 degree coolers use this principle. Get more that 15 degrees above 32 and it is lost. Most walk in and beverage coolers actually go to 28-29 degrees, just for the efficiency. This creates a micro ice layer on the product surfaces. Remember, that the start inrush is about 17 times full run current. It’s not the long running time that kills a power bill, but the short starts and stops. A well balanced and designed cooler will run 22 to 23 hours a day. Unfortunately, where I live the temp varies to much to achieve this all the time. Hence why we all overdesign capacity. The reach in cooler companies have to design for Alaska to  New Mexico, to Rocky mountains high. And do it with cap tube systems that are much more sensitive to precise conditions..

     Again, can’t say enough that one should talk to True engineering before making a change or decision. Parts or sales won’t know the answers, only the design or engineering people do.

[olivero]

True,

 

I do agree it be more expensive, shorter run times, more starts and stops but the original question was regarding damaging the unit. I think the unit will survive, and it may be more expensive but maybe selling wine makes up for that

 

Designing walk ins and larger systems definetley takes up more variables and factors and I really doubt you could revert a walk in cooler to a wine storage, too many things would get messed up in the process.

 

I also think you should call True Engineering and speak to them regarding it, If the unit goes down due to the fact and you don’t have valid proof of it being okay from the Manufacturer, all warranty will be lost (if any is there still)

[john]

Any response from True on this smithd? I’m curious to find out what they recommended!