View Full Version : Delfield 6151 Freezer problem
12-24-2008, 05:14 PM
I hope I can get some help, I work in the trade(5+years), and have a Esco Universal recovery card. Problem is a Delfield freezer, model 6151-S with a Copeland compressor, 17.5 ounces R404A. Owner said the door was left open over night, and when unit was restarted it would not pull down below 45 F. I checked the door seal, Box light switch, defrost timer & contacts, and condenser airflow. Compressor starts fine, no odd noises. Gauges show 175/190 psi on the high side, 10/5 psi on the low. Suction line temp. was 55 F There is a "Crankcase press. regulator in the Evaporator box with 2 fans (operational). I did replace the cap tube filter, and confirmed that the lines were not plugged. The CPR is a Sporlan CR0-4 0/50,which I opened and cleaned, and confirmed flow with nitrogen. I have never thrown the gauges on a properly operating unit, so I am not sure what the normal operating pressures should be, but the 10/5 psi. on the suction side with a 70 F box temperature sounded low to me, but hey that's why I'm here looking for info. Will anybody take a stab at this?
12-24-2008, 05:43 PM
Did you take a reading before the CPR.
12-24-2008, 06:03 PM
How long did you allow it to run?
Typically units with CPRs pull down slowly because they tend to keep evap temp up in order to reduce load on the compressor.
If it was at room temp, you could have an hours long pulldown on your hands.
5/10 seems a bit low on the low side for R404. I'd expect about 15-17 in general, but have not worked on that unit specifically.
12-27-2008, 10:09 PM
sounds like you have a partial plug in the system to me
12-28-2008, 12:09 AM
Is it possible to have the suction valve stick? Ya, I know it should be blown off the seat with suction pressure entering the compressor, but I am at a loss here for another idea. I did install a new liquid line filter at the cap tubes, but I confirmed flow with N2 at the compressor hi side service valve, and the cap and piston removed from the CPR. I placed my finger over the cap port of the CPR, and felt N2 pressure build rapidly. Maybe I could put N2 at the inlet port of the compressor, and listen for valve noises with a stethoscope. Can anybody else pull up some experienced advice?
12-28-2008, 05:52 AM
Let's move this to the proper forum!
12-28-2008, 05:55 AM
CPR, can't be tested by just feeling pressure build up quickly.
12-28-2008, 07:22 PM
Do you have air flow across evaparator coil
You did say that the door was open all night
It could be a block of ice up there :confused:
12-28-2008, 07:43 PM
Another thing to consider is alot of times when a small reach in freezer is down for any reason on start up a shortage of refrigerant in the system or a partially plugged cap tube wont allow the unit to pull down to temp. When it was running and down to temp full of product it had the capacity to some what maintain cold enough temps with extended run times and what not. With that little refrigerant in the system it wouldnt take a big leak to make it unable to pull down. Head and suction look low to me. I would assume you checked the evap and its most likely melted by now.Thats what ive experienced.
12-29-2008, 06:27 AM
if you weigh in the charge after installing a new drier i would replace the cap tube on this unit or try to clean it
the unit has poly oil and over time when the condenser gets plugged the oil breaks down and plugges the cap tube
i haven't had good luck cleaning but cutting off an inch on both sides has worked
12-31-2008, 09:45 PM
Assuming you evacuated to below 400 microns and not undercharged(add a couplemore oz.. to see if you can get abetter head press.) if this doesnt work, most likely cap tube partially restricted. How long does it take for press; to equalize during off cycle or are they, comp. could of overheated when cust. left door open, reason for cap tube to resrict flow, blame the cust...lol,just kidding, but i would let him/her know that a overheated comp. has been compromised and could lead to pre-mature failure.. good luck and cover all your bases,dont forget to check s.h and subcooling
12-31-2008, 09:59 PM
Probably been overheated condensor. Captube time.
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