2 techs cannot figure it out

[Stephanita]

hello,

I purchased a new walk in cooler, and it was professionally installed. When powered up it cooled perfectly and continued to cool. when we came back to the restaurant the next morning it was up to 60 degrees. It stayed at 60 for about two hours, and then began to cool perfectly again. two techs looked at it and checked it and could not find a problem. the next day it happened again. almost like a pattern. (Please note that I mean Degrees Farenheit and Not Celsius)

[frank]

Possible the defrost time too long or defrost termination not working correctly

[Stephanita]

also there is ice on the copper coils inside the walk in

[rbartlett]

also there is ice on the copper coils inside the walk in

post some pictures if you're able

cheers

richard

[Stephanita]

here are the pictures. Cooler is cooling fine now, but I do not see any water dripping from the condensation pipe. Condensation coils have ice.

[Deejey]

Not enough information provided to be able to provide any sort of assessment other than wild guesses as it could be a number of things.
What product/s are you storing? What temperature is the room supposed to be at? what refrigerant is it on? What type of defrost?

[Andy W]

Definately a defrosting problem probably electronic, re programming required may also be hot gas defrost and evap fan starting too early or running with defrost.

If the equipment has been selected individually and a control panel "custom" built the problem will lie with the panel controller or the way it is wired, I have come across similar panels before with evap fan on with heaters/hot gas valve, compressor and heaters on together, termination stats wound up to the max trying to cure ice up problems.

Are you losing a lot of product or is the product still ok when you probe it, is the temperature display and oblong shaped electronic item or a dial thermometer.

Sounds like you need a more experienced engineer.

[Stephanita]

It should be around 35 degrees F , I am storing food in it. The refrigeration is r22.The thermometer is a dial. A third tech looked at it today, and said that it needed more refrigerant. It seems to be doing fine. there was some ice on the coils, but the compressor went off and the ice went away. But if all it needed was more refrigerant, then why did the other two techs not recognize that? I am leaving for mexico in the morning, and I hope the problem is solved.

[headgasket]

you are short of gas, you have a fan delay on the evap with a klixon on the coil, short of gas the evap fans will cycle off and on, and will balance out untill you open the door and it will go off for some time. get the cow boys back to fix it pronto

[Toolman]

Look at the size of the TX valve !! Geez must have been left over from a larger job . I guess its capacity is right if its working now . Lucky half the inside of that fan coil is for the TX valve. Is that a liquid line soleniod in there as well? Why bother its medium temp isnt it not a freezer ?

[TopMechanic]

Yeah, sounds like a defrost cycle problem, a longshot would be water in the system freezing at the TXV, after running for a while. Probably low on refer to boot.

[John Wood]

Brand new system on R22!!!! There is no hope is there.

[Snowman123]

Looks a bit short on refrigerant or the valve size is wrong. Get a Danfoss TEV on it with a no2 orifice to start off with and see how she goes.

[abdulazman]

Hi Stephanita,

Appears to be defrosting problem but when you describe of undercharge then it could probably be the system leaked. After installation have the pressurization and evacuation test properly done up?

[ernestlin]

hello, stephanita, is the 1st and 2nd photo which you posted taken in system defrosting time, and 3rd taken in working time?(BTW, I regard the dispenser is too near to the TEX), That's OK from observing the frost on the tube. I think the problem may be at the defrost control, the temprature is set too high, or the defrost time is set too long. I dont know which type is your defrost control? Can you tell me?

[Rob S]

Who ever keeps coming out isn't staying there long enough.
Theres no reason to have frost on the evaporator of a cooler. I dont see the fan running in the 4th pic.

Issue is either.. Defrost (would need couple of defrosts for a 35F box), Air flow (fan is shutting off maybe), TXV superheat isn't set right.

[Hanle]

The problem happened in the morning maybe the ambient temp. was cool and the low pressure cut-in setting could be too high.
Hope it helps.
Han Le

[ben_harper]

Han le might be onto something...

I assume the Unit is running on LP, and the T/stat is operating the liquid line solenoid.

Perhaps set the LP on the unit for safety (cut in at 25PSI/diff 20PSI)

[dogma]

Hi guys.

I've come across a similar prob with display freezers using carel pwr splits. The evaporator and cabinet probs were wired ass about. Defrost termination was dependant on cab temp not coil temp.

I'm guessing it's a controll fault.

???

cheers


dogma

[leftjobrunning]

Just a stab in the dark, do you shut off the electricity at night? Or do you have some kind of timeclock on this circuit that does it for you?

Do I get the prize??? no... ah well.

[Abe]

hello,

I purchased a new walk in cooler, and it was professionally installed. When powered up it cooled perfectly and continued to cool. when we came back to the restaurant the next morning it was up to 60 degrees. It stayed at 60 for about two hours, and then began to cool perfectly again. two techs looked at it and checked it and could not find a problem. the next day it happened again. almost like a pattern. (Please note that I mean Degrees Farenheit and Not Celsius)


Theres nothing wrong with the refrigeration system
You have a control problem
Check your sensors

[slingblade]

Theres nothing wrong with the refrigeration system
You have a control problem
Check your sensors


I am inclined to think that there is a 24 hour mechanical timeclock for defrost and a group of pins around the 2-3 hour mark are set ON whilst the other 21-22 are OFF.
I may be wrong, but the problem here sounds like it is begging for a stupidly easy answer.