Need Help to Trouble Shoot DN5591 Refrigeration Problem

[fhamann]

I have a DN5591 bottle drop vending machine.  Recently I noticed that the evaporator was clogged with ice about 75% (iced over, mostly at the top).  I unplugged the compressor to allow it to thaw out and plugged it back in.  The evaporator fan was blowing normally.  The door seal looked fine and the product delivery door was working normally. The next day, the ice had returned and was covering the top 50% of the evaporator.  The sodas were cold to the touch (seemed to be at normal temperature). I listened to the machine for several minutes and noticed that the compressor would not cycle off (it was on all the time).  I adjusted the thermostat.  It was originally set to the 1/2 way setting.  With the product door closed, I turned the thermostat counter-clockwise slowly until the compressor turned off.  It would not turn off until it was almost completely (within a few degrees) of full counter clockwise, possibly in the "off" state.  I allowed the ice to melt, and rotated the thermostat slowly clockwise until the compressor started, just a few degrees CW.  I listened to the compressor for several minutes, and it remained on, not cycling.  I came back the next day, and the ice had returned, 50% coverage, product was cold.

 

Is this a thermostat problem or a refrigeration deck with low Freon?

Should I replace the thermostat?  (This machine does not have the defrost circuit.)

If the refrigeration deck has low Freon, can it be refilled or must the entire deck be replaced?

What else can be wrong?

 

Thanks for your help.

Regards,

Frank Hamann

Orange, CA

[AZVendor]

It sounds like it's low on freon.  You can have someone recharge it on location for you.  Your thermostat should always be at 3 1/2.  

[fhamann]

Hi AZ,

Thanks for the tip.  Would my local vending repair guy be able to recharge the Freon, or do I need to ask a refrigeration repair person to do this?  How much should I expect to pay for the Freon recharge service?

Regards,
Frank

[ABCVending]

Having the same issue with a 5591 - pretty sure it is low on refrigerant, had a tech take a look at it on location - he put a bullet piercing valve on because there were no service ports and tried adding a bit of R134 but it didn't seem to want to hold pressure so recommended deck replacement.

Bought a new deck (they are not cheap) and have it on hand, have not replace yet because A.  looks like a big project for a ham & egger like me, can do it but will probably take me a couple hours at least. and B. it's still operating, cabinet temp holding around 45 which is kind of high, but not enough to generate complaints from the account.

Plan to take the old deck out in the coming weeks and see if I can get someone to service the old deck and get proper service ports soldered on and re charged properly.

 

ABC

[AZVendor]

2 hours ago, fhamann said:

Hi AZ,

Thanks for the tip.  Would my local vending repair guy be able to recharge the Freon, or do I need to ask a refrigeration repair person to do this?  How much should I expect to pay for the Freon recharge service?

Regards,
Frank

If he's a good repairman and is trained to do refrigeration work then yes.  My service call to add a line tap and freon is less than $200.  I wouldn't go over that.

[fhamann]

My regular repairman recharged with freon the unit and the icing problem has gone away.  He says that if it lasts 6 months it was successful.  If it  dies before 6 months it has a "find-able" leak and can be repaired.  If it starts acting up after 6 months the leak is too slow to find, and the deck will need to be replaced.  He changed me $150,  I hope it lasts a long time.

[orsd]

For the slow leaks UV dye is the answer.

[AZVendor]

Your repairman is mostly correct as that is what I tell my customers with the exception that the longer a recharge lasts the smaller a leak is and when it's a small one we have to again recharge it but with the addition of UV dye.  Then when it leaks down again we can use a black light to find where the dye leaked out.