Onboard fridge stopped working - any ideas?

[tony_lavelle]

The Danfoss fridge in my Westerly Corsair was installed in 1988, so it's 28 years old. The cold compartment is in the galley but the compressor etc are in the cockpit locker. Last weekend it just didn't get cold, though the compressor motor was whirring and felt hot. I can therefore assume the thermostat and thermal cutout are OK.

Before I consign the thing to the marina skip, is there anything I can do to see if it can be resuscitated? My guess is that the gas has slowly leaked out and there's now not enough left.

 

[Richard10002]

Mine did the same a few weeks ago. The compressor ran almost continuously, but it didnt get as cold as usual. I suspected gas, but had it looked at and the diagnosis was the thing inside the compressor that did the compressing was worn, so not enough compressing going on. He had a gizmo that smells for leaking gas, and it registered nothing leaking.

The engineer couldnt find a replacement compressor, so I bought a new fridge. £515!!!

 

[PaulRainbow]

Mine did the same a few weeks ago. The compressor ran almost continuously, but it didnt get as cold as usual. I suspected gas, but had it looked at and the diagnosis was the thing inside the compressor that did the compressing was worn, so not enough compressing going on. He had a gizmo that smells for leaking gas, and it registered nothing leaking.

The engineer couldnt find a replacement compressor, so I bought a new fridge. £515!!!

Hmmmm If it had a leak and all of the gas had gone, how would his leak detector detect any gas ? Besides which it isn't filled with gas it is filled with liquid refrigerant.

 

[Richard10002]

Hmmmm If it had a leak and all of the gas had gone, how would his leak detector detect any gas ? Besides which it isn't filled with gas it is filled with liquid refrigerant.

I have no idea how things work, other people use the word gas, so I do. He had a good look, listen and feel, waved an electronic wand gizmo around, and made his diagnosis. It seemed to make sense. He wasnt selling me a fridge and, if he had been on some kind of make work scam, he could have offered to fill it with refrigerant, and charged me more.

 

[Adethefridge]

Hmmmm If it had a leak and all of the gas had gone, how would his leak detector detect any gas ? Besides which it isn't filled with gas it is filled with liquid refrigerant.

refrigerant is in a liquid state in certain parts of the system and a vapour in other parts of the system
The engineer should of attached a set of gauges , if the system was low or out of refrigerant the low side would probably be running on a vacuum , if the compressor was not pumping the low side would be showing a higher than normal suction pressure
Ie
normal running pressure = 5 psi
Low refrigerant = 0 psi or a vacuum
Comp not pumping = 20+ psi
Also if the compressor isn't pumping correctly the compressor runs very hot and often a hissing noise when you switch the compressor off ( refrigerant leaking through the damaged valves )

 

[NickRobinson]

Ditto folks... not having huge battery resources afloat I’ve not bothered sorting the boat's fridge. When I power it up by moving the thermostat dial off the stop the compressor runs for a few seconds then that stops and a computer sized fan in the external fins cuts in. No heating externally or cooling in the fridge. I guess this is a 'failed start' mode due to the refrigerant being long gone?

 

[PaulRainbow]

It could be that it's out of refrigerant.

Being fitted in 1988 your system will have been filled with R12, that's the one that eats holes in the ozone layer. R12 systems don't require periodic servicing, unlike modern systems that use the like of R134a, so if it's out of refrigerant you have a leak.

A crude way of checking is to find the service port, brass cap with a valve under it close to the compressor, and depress the valve. Should be under a bit of pressure. Take care not to squirt yourself in the eye and don't let the refrigerant near a naked flame. Don't be smoking when you do it. Be careful.

 

[superheat6k]

The refrigerant fluid is both a liquid and gas according which part of the system it is in. It is by changing its state that produces the refrigerating effect. In the fridge industry refrigerants are commonly referred to as 'the Gas' rather than 'the Liquid'.

A unit from 1988 will almost certainly be using R12, the ubiquitous 'Freon' and long since banned. If you manage to find someone who has any you would be breaking the law if you charged your system with it. There were some direct replacements such as MO49, but even that will be difficult to find now. Most systems that came after R12 used R134a but this needs a different oil so you can't simply just change the gas, you need to change the oil as well and these small compressors were never intended to have an oil change.

The other issue is where has it gone. If the leak isn't found and fixed then a re-charge may only last a few weeks. You suggest it not working is a recent situation, so either a leak has developed recently or perhaps a valve inside the compressor has failed. I doubt it would be worth even a fraction of the cost a fridge engineer will charge to see if it can be fixed.

Regrettably likely time for the skip as muted.

 

[Adethefridge]

Ditto folks... not having huge battery resources afloat I’ve not bothered sorting the boat's fridge. When I power it up by moving the thermostat dial off the stop the compressor runs for a few seconds then that stops and a computer sized fan in the external fins cuts in. No heating externally or cooling in the fridge. I guess this is a 'failed start' mode due to the refrigerant being long gone?

Unlikely your fridge a low pressure switch detecting low refrigerant
More likely a compressor fault either siezed of winding fault,
Compressor tries to start draws too much current and goes out on its thermal overload resets 2/3 mins later and tries again
Buzz click-----buzz click

 

[FulmarJeddo]

Tony,
Not sure where you are moored on the Medway, but there was a refrigeration engineer on Gillinham Pier. I can't remember the company name and can't find it on Google, but he shared the workshop with A&B sails. He was very helpful when I messed up the installation of my Waeco fridge and lost all the gas in a few months. I was going to take the boat alongside the Pier for him to have a look but the weather turned bad the day I had arranged to go there, so had to cancel.
I ended up refilling the fridge myself with a car air con top up kit, although it seems that option probably isn't available to you. There is a very good article on refrigeration on Forum member Viv Cox's web site.http://coxengineering.sharepoint.com/Pages/Refrigeration.aspx

David

 

[Heckler]

The refrigerant fluid is both a liquid and gas according which part of the system it is in. It is by changing its state that produces the refrigerating effect. In the fridge industry refrigerants are commonly referred to as 'the Gas' rather than 'the Liquid'.

A unit from 1988 will almost certainly be using R12, the ubiquitous 'Freon' and long since banned. If you manage to find someone who has any you would be breaking the law if you charged your system with it. There were some direct replacements such as MO49, but even that will be difficult to find now. Most systems that came after R12 used R134a but this needs a different oil so you can't simply just change the gas, you need to change the oil as well and these small compressors were never intended to have an oil change.

The other issue is where has it gone. If the leak isn't found and fixed then a re-charge may only last a few weeks. You suggest it not working is a recent situation, so either a leak has developed recently or perhaps a valve inside the compressor has failed. I doubt it would be worth even a fraction of the cost a fridge engineer will charge to see if it can be fixed.

Regrettably likely time for the skip as muted.

There is a bottle of Freon R12 in my garage, left over from the late 80s. Must be a couple of kilos if any one wants it.
Stu

 

[windrose]

look on the compressor it will tell you what gas it uses, and how much....normally about 65grams....

 

[tony_lavelle]

So many excellent and helpful replies in such a short time. Thanks everyone - what a great forum this is!
Tony

 

[Jabs]

There was someone selling a compressor/condenser and an evaporator in the 'For Sale section.
It's plug and play so could be an option!

Tony.

 

[owen-cox]

Unlikely your fridge a low pressure switch detecting low refrigerant
More likely a compressor fault either siezed of winding fault,
Compressor tries to start draws too much current and goes out on its thermal overload resets 2/3 mins later and tries again
Buzz click-----buzz click

This wont happen if it is a 12/24V fridge as they do not have a thermal overload or a pressure switch. they are protected electronically. the only way to know what reason it has stopped for is to connect the LED indicator as per manual and then see which fault is shown. I would suggest that the batteries could be low and that may be the problem.

 

[owen-cox]

There was someone selling a compressor/condenser and an evaporator in the 'For Sale section.
It's plug and play so could be an option!

Tony.

I had a look at that and the kit is at least 20 years old and so I would not buy it as they have obsolete compressors that havent been made for at least 15 years. the indel B compressor ( which that one is) was notoriously bad for starting as well. That one would also be best consigned to the skip.

 

[Richard10002]

You could just buy a new compressor but, as it would need fitting, and gassing, and you would still have a 1988 fridge, it might be worth buying new.

 

[PaulRainbow]

The real answer to this one is to get someone to look at it.

If it's a mechanical or electrical failure, you need an engineer.

If it's out of "gas", you need an engineer. Fix the leak and recharge.

I think a leak is the most likely suspect. Get someone to come and check it. It needs connecting to a proper setup, if the guy gets a "gas sniffer" out throw him overboard. Proper equipment will confirm or deny a leak in minutes. UV dye pumped through the system will locate the leak and if it can be sealed an update to R134a will see you up and working again.

A new system will cost you from about £400 plus fitting, so to me it makes sense to spend a few quid determining the fault in the one you have.

 

[owen-cox]

The real answer to this one is to get someone to look at it.

If it's a mechanical or electrical failure, you need an engineer.

If it's out of "gas", you need an engineer. Fix the leak and recharge.

I think a leak is the most likely suspect. Get someone to come and check it. It needs connecting to a proper setup, if the guy gets a "gas sniffer" out throw him overboard. Proper equipment will confirm or deny a leak in minutes. UV dye pumped through the system will locate the leak and if it can be sealed an update to R134a will see you up and working again.

A new system will cost you from about £400 plus fitting, so to me it makes sense to spend a few quid determining the fault in the one you have.

As already said by another above it is not possible to update to R134a as they use ester oil for R134a and mineral for R12. they are only interchangeable in compressors that you can dismantle to get the old oil out. Drop in replacement gasses were available for a time but now the change to R134a is well established they are not available any more.

The dye is not good to add to a system of this size as the quantity needed to find a leak is so high there would almost need to be more dye than refrigerant considering that the total volume of refrigerant in these little circuits is about 38 grams. Finding a leak is in my experience a case of using soapy water as the amount is too small for a refrigerant sniffer as well. I tried everything to find leaks with my 15 years experience of yacht refrigeration in mallorca and it was soapy water that found more than any other especially if I pressurised the system with dry nitrogen first. I would imagine from experience that a sudden loss of gas is due to corroded pipes running through the bulkhead to the fridge cabinet. The piping at this point is usually enameled aluminium and is very prone to rotting away with the sweating of the pipes. this will be about £50-£100 to change and then a couple of hours labour to vacuum and refill the system. there may be travel time for an engineer to get there and refrigerant and nitrogen maybe so for a more than 20 year obsolete system I would suggest the outlay of probably £200 is not cost effective when you take into account the fact that the compressor may fail tomorrow and be then completely wasted money. Personally I think if you cannot do all this yourself it is uneconomical to repair. I would buy a new system and fit it yourself which will save quite a bit of money and mean you get a fully guaranteed working system that can be repaired in the future if needed.

 

[PaulRainbow]

As already said by another above it is not possible to update to R134a as they use ester oil for R134a and mineral for R12. they are only interchangeable in compressors that you can dismantle to get the old oil out. Drop in replacement gasses were available for a time but now the change to R134a is well established they are not available any more.

That is simply not correct. It is perfectly possible to retrofit R134a. R134a uses PAG oil, not ester. R12 mineral oil can be replaced with POE oil (which is an ester oil) and will mix with small amounts of mineral oil. I've done several retrofits and every single one has worked perfectly well.

The dye is not good to add to a system of this size as the quantity needed to find a leak is so high there would almost need to be more dye than refrigerant considering that the total volume of refrigerant in these little circuits is about 38 grams.

A small amount of polyol oil with dye in it finds leaks easily.