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jammy23
22-06-2014, 12:37 PM
Hi, I've been working on an Osborne bottle cooler which hasn't been achieving temperature.... suspected it to be short of refrigerant due to high internal temperature and lack of cooling back to compressor. There was no service point to add my gauges to and the service point too short to add a temporary one to check unit pressures. I used a quick release type service tap and reclaimed what was in and was a tad short so added a braised service point and regassed after leak checking.

When I ran the unit the temperature began to drop , although seemed a little slow and seemed to take a little longer than would probably be expected. The temperature only came down as far as 11 degrees yet the pressures seemed reasonable I.e not running in a vac or any signs of possible blockage etc, the condenser is clear and both condenser fans are running.... also both internal fans are running yet the compressor is ridiculously hot. After around a hour to hour and half the compressor temperature got up to 94 degrees, I know compressors on some bottle coolers can run a little warmer than other systems but not as hot as this is. I checked electrics on it and everything seems good but was suspecting perhaps it isn't pumping as efficiently as it should be and just generating huge amounts of heat.

Any ideas what could be causing it, and best method of checking pump quality? I thought about removing charge and running it with nothing in to see how low of a vac it can pull but not sire what would be a good result, should it be strong enough to pull my gauges into complete vac as low as they will go and if not then that's the issue?

Don't really want to condemn it if it isn't faulty but I can't see what else it could be....I've only had one compressor that's needed pump testing before and that had rotarlock valves on so could do it with charge in system and when tested it barely moved.

jdunc2301
22-06-2014, 08:16 PM
Compressor IMO

install monkey
22-06-2014, 08:20 PM
usually the pot will cook itself, dirty condenser, running its nuts off due to doors left open and usually jammed under a counter next to the glass washer, only way to prove this is to degas it, cut the suction line, where you can re joint it if req, pinch off the suction stub as you have a gauge connected to the charging stubb, run the pot to see if you can pull over 12 in vac

install monkey
22-06-2014, 08:20 PM
could be discharge valve leaking

charlie patt
22-06-2014, 08:35 PM
also prone to blocked capiliary/ run it switch it off and sea how quick pressure equall up if not not getting enough suction comp will run hot to test comp i would reduce preesure and sea what vac it will pull not ideal but what else can you do also had issues where comp been changed or reevap coil made bigger and just a little more than base charge required check the above put on a clampmeter and run it also a lot of those osbournes came out with 290 then converted and the new gas levels they put on the labels where undercharged

jammy23
22-06-2014, 08:36 PM
There is no information on the actual compressor....must be the original though as there was no service point on it. One door gasket needs replacing but nowhere near bad enough to cause it to draw in enough heat to prevent temperature being achieved. Condenser coil is clear as a whistle, if you shine a light through to can see both condenser fans...it is tucked in under a counter so airflow isn't great as it is in a bar, but even being out in the open where airflow is perfect it still creates far too much heat. The discharge temperature feels hot as expected and you can feel the temperature change from the top of the condenser to the bottom, I have had the back off to see if the unit is cooling all the way across the evaporator which it is.....the only thing I can put it down to is an issue with the compressor.

jammy23
22-06-2014, 08:43 PM
Blocked capillary was my first thought but pressures run around 20 psi ish....the actual running temp on gauges was -2 degrees and when switched off equalises out fairly normal not slow as you would expect with blockage. The gas charge on it is 240g and is on R134a...I checked windings and capacitor just in case anything was amiss there but all spot on. Think best bet might be to de-gas and run on empty and see what it pulls just not sure what is a good bench mark to aim for. It does pull the pressure down when starts up from around 60psi down to around 20psi and then stays around there until switched off then goes back to original standing pressure.

cadwaladr
23-06-2014, 12:21 AM
clean the condensor with mr muscle what looks clean may not be ?

jammy23
23-06-2014, 12:05 PM
Reclaimed refrigerant today and ran with nothing in and compressor would only pull -9 inHg on gauges and took it around 5 minutes just to do that so pretty safe to say it's had it.

Cheers for advice though guys much appreciated.