Fridge problems

[Rigger]

Having worked perfectly since for the past 5 years my fridge has chosen this heatwave to pack up on me!! It may well be as old as the boat (1990) and from looking on the web I think it is a frigomatic model K with a holding plate and a now discontinued keel cooler which consists of the bronze pipes carrying coolant, simply covered with a stainless steel plate (as opposed to the modern one piece keel coolers).
As I understand it the compressor simply pumps the coolant around the pipes which cools the holding plate ,which is designed to maintain its coldness for several hours when the fridge is switched off. What I don't understand is why the holding plate gets considerably colder when the engine is running- is this just a simple case of increased voltage from the alternator,rather than the domestic batteries??
Am I correct that the pipes carrying the coolant are self-sealing and therefore can simply be disconnected at the compressor?
Looking on-line it appears that this is a pretty ancient set-up and I'm wandering whether I would be better aiming to replace the whole lot or try to rectify the current fault by simply replacing the compressor which I reckon is the knackered bit.
Any thoughts much appreciated.

 

[charles_reed]

Almost certainly it's due to loss of refrigerant. Have a look and check on the unit the type of refrigerant - if Freon (12) it might well be less of a problem to replace the whole unit. The replacement to chlorofluorocarbon (22) is expensive and corrosive.
Best done by a refrigeration engineer on site, without taking out the unit.

 

[Bosun Higgs]

repair dont replace. you have an excellent upmarket system with the holding plate and keel cooler - much better than the standard small boat fridge.

why do you say its knackered? whats the problem?

 

[abraxus]

I have recently had a similar problem on an old (1990 ish) Norcold fridge. My batteries got discharged by the fridge due to a power outage at the marina and since then the fridge didn't work on 12v. I could hear the compressor starting but it would cut out after a few minutes.

I too was about to replace my fridge but after reading a lot online became aware that they can pretty sensitive to the voltage they're receiving. It also gets a bit warm in the compartment behind the fridge which doesn't help. So after a fitting a 12v computer fan behind the fridge and replacing the old batteries and getting them fully charged the fridge seems to work fine now.

I'm also considering fitting a 12v to 12v DC converter behind the fridge as this will take the voltage from the batteries, even if a little discharged, and pass a constant voltage to the fridge.

Anyway, my point being that as the frdige seems to work fine with the engine running it may be worth checking batteries and charging first before replacing the fridge or compressor.

 

[Rigger]

repair dont replace. you have an excellent upmarket system with the holding plate and keel cooler - much better than the standard small boat fridge.

why do you say its knackered? whats the problem?

Basically nothing happens when I switch it on!! Initially there was a very quiet "beep" every 30 secs or so from somewhere,now even that has stopped.The compressor is mounted in a cockpit locker and looks a bit rusty. I think at one time there was a quiet humming sound coming from it (like an electric motor wanting to start but stuck) but now all is quiet. Believe it or not I only found out recently there should be a control unit for it. I don't think I've ever seen it and am not on the boat at present to go searching.Is it possible it has been fitted without a control unit, previously I just used to switch it on and off at the circuit breaker on the main control panel, I believe the control unit has a fuse so this may have gone which would explain the complete lack of any life.

 

[Rigger]

I have recently had a similar problem on an old (1990 ish) Norcold fridge. My batteries got discharged by the fridge due to a power outage at the marina and since then the fridge didn't work on 12v. I could hear the compressor starting but it would cut out after a few minutes.

I too was about to replace my fridge but after reading a lot online became aware that they can pretty sensitive to the voltage they're receiving. It also gets a bit warm in the compartment behind the fridge which doesn't help. So after a fitting a 12v computer fan behind the fridge and replacing the old batteries and getting them fully charged the fridge seems to work fine now.

I'm also considering fitting a 12v to 12v DC converter behind the fridge as this will take the voltage from the batteries, even if a little discharged, and pass a constant voltage to the fridge.

Anyway, my point being that as the frdige seems to work fine with the engine running it may be worth checking batteries and charging first before replacing the fridge or compressor.

It doesn't work at all now,with or without the engine running.

 

[MAURICE]

Hi Rigger
I too had a problem with my fridge whilst in Spain. Firstly check out the web site fix my fridge which you probably have done.
The next stage is to take off all electrical connections and clean them up. Make sure they all fit tight if still no go then take a feed directly from the battery as you are aware the voltage is a bit sensitive. lastly check the small electrical box of tricks that checks out the voltage for the fridge etc. This happened to be my problem a fridge engineer put in a new one and all was then well. Apparently if the compressor works it works so if yours is starting and stopping its electrical. Hope this helps
Maurice

 

[nigelmercier]

Am I correct that the pipes carrying the coolant are self-sealing and therefore can simply be disconnected at the compressor?...

No, they have a lance which pierces a cap when screwed together, you can't dismantle without loss of coolant.

 

[vyv_cox]

No, they have a lance which pierces a cap when screwed together, you can't dismantle without loss of coolant.

My son Owen, who had a yacht refrigeration and A/C business in Mallorca, tells me that these always leak over time. When installing systems with them he would remove the fittings and braze up instead. But he has the equipment to gas up without needing the simple connectors.