How cold should the refrigerator get?

weightless

Super Anarchist
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These things likely draw more current as the voltage drops. Yeah, check all the connectons. "It's always the connections."
They do. They also have a low voltage cut out which might be an issue but should show an error on the LED if it is installed and working properly.

I'm thinking that more specifics about how the system is behaving might make speculations on the problem a bit less random.

FWIW, the thermostat is easy to test. I don't recall the voltages on the circuit so be careful. The thermostat can be shunted out at the switch inside the box or at the controller. Short the connections, leave the box shut for a while and see if it keeps getting cold. If the thermostat is working but can't be set cold enough it can be adjusted (there's a set screw) or, as a short term hack, by moving the sensor to a warmer part of the plate.

Okay, googled it. Here's some official looking stuff.

http://files.danfoss.com/TechnicalInfo/Dila/06/bd_compressors_04-2007_pk100c802.pdf

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Pilott

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Just had a thought: another thing that can cause high amps & no cooling is air/ moisture contamination of the refrigerant

 

Coolerking

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LBC
Just had a thought: another thing that can cause high amps & no cooling is air/ moisture contamination of the refrigerant
This is correct, and it is for this reason that we really try and get those who are not trained in HVAC and especially these types of systems to NOT try and "just add a little to it"

The site linked above to Richard Kollman is a great place to start.

The non-condensables introduced by incorrect procedures occupy space in the condenser and stay there, thus decreasing capacity and eventually they acidify the oils, which in turn eats the coatings on the windings. 

Heat kills compressors.

 

weightless

Super Anarchist
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FWIW, standard refrigerator temperature is 4°C for food safety.  Or 39°F, 312°K, etc.    
The OP reported ~40-45F and 45F. That might be overly warm but when and how he sampled the air temp is a mystery and could matter. I suspect the OP has a system that regulates the air temperate indirectly and with quite of lot of hysteresis. FWIW, as I read the OP's reports I'm not sure there is a problem with the system. I think it'd be interesting to know if the compressor runs continuously and at what speed. I wouldn't mess around with the refrigerant or even put gauges on it without knowing a bit more about the details of operation.

 
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Zonker

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Is it air cooled? If so have you cleaned the cooling fins of dust and cat / human hair?

Is it water cooled? Is the sea water pump pumping lots? Is the strainer clear? Is the thru hull free of lots of barnacles?

when the compressor kicks on, it can also give me a low voltage alarm.
Check the wiring!

 

Reference

Member
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Thank you everyone this very helpful. To the question of temperature sampling, I used a an IR non-contact thermometer. It sounds like I will need to monitor temps and current/rpms over a longer period, before determining if there’s really anything wrong with this or not.  I will follow up here after this weekend.

 
I would follow Coolerkings advice above.  It's very easy to mess one of these up and they are not that forgiving.  It sounds like a combination of non condensables and incorrect charge, but who knows.  I would call a tech, does not have to be marine someone who works on small resturant chillers cool displays, ice makers etc.  Have them evacuate, pressure test with nitrogen, if needed flush pull a vacuum and recharge.  If the unit has service valves on it all of this will be fairly quick and easy.  If you are in the boondocks or remotely cruising then yes pursue further advice for trouble shooting, but start with someone like Richard Kollman he is great and usually is fielding a huge volume of free advice.

 
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