Do fridge compressors degrade over time?

[[2574]]

I've had my fridge compressor regassed a couple of years ago but its performance is not what i'd call good. The boat is ten years old and the compressor is original. It seems noisy to me and the fridge is cool but not cold. And it seems to take a lot of 12v juice. Are the more modern units (ie recently manufactured) much more efficient than ten years ago? Or are the units just knackered after ten years and need binning?

I can't add more insulation around the fridge without dismantling the boat interior - (and I'm not about to do that) so my only perfomance gain I think can be by upgrading the compressor. Is it worth a try do you think?

TIA

Rob

 

[Jonny_H]

If you've had to have it regassed then original gas must have gone somewhere - I therefore suspect you have a gas leak and if you didn't fix this before you regassed the unit then the gas you put in 10 yrs ago will have leaked away too.

If you have no gas then yes, the compressor will run too hard for too long and the fridge won't get cold.

The modern units are slightly quieter and possibly more efficient, but I suspect if you get the gas leak fixed then yours will be fine. A new compressor without finding the leak (probably in the pipes or the plate) won't make any difference.

The trouble will be finding the gas leak - often at an inaccessable point in the pipe - in which case putting in a new one becomes an easier option!

Jonny

 

[Piers]

This degradation happened on my previous old 1989 car. Each year, the air con would be less efficient and I would have to have it re-gassed. At the last place I took it to, I asked the owner of the garage why this should be. He responded that older air con systems were designed for gasses which are now banned. The new gasses have a smaller molecule which can leak past the original gaskets. This is why older systems become less efficient with new gasses and need topping up.

Can someone verify whether this sounds true, chemically?

 

[Skyva_2]

I have also heard that it is sensible to run the frig or aircon regularly to help prevent the seals from drying out.

 

[TonyS]

I have just had mine re-gassed today. It is a Waeko unit. They have special connectors between the compressor and the pipes to the evaporator to allow the pipes to go through a small hole in the fridge cabinet before connecting up. The engineer told me these connectors (steel edge into copper) need tightening every year or so. He was amazed to take a whole turn on mine, which explains the leak. He said he would be out of work if boat owners regularly retightened them!

 

[Bav34]

Tell more Tony. Who? Where? How much?

Good to know for when mine needs doing /forums/images/graemlins/frown.gif

Cheers

 

[SimonJ]

A tight system should not need regassing. If you have to top up you have a leak. The leak will get worse as when you regas the new gas will not contain the lubricant for the pump seals which will then wear even faster. If the leak is on a joint it will still be there.
A modern sealed unit (eg a Danfoss which has most of the market) is more effficient than its 10 year old predecessor and if it is similar to your home fridge it will be hermetically sealed. If so encapsulated leaks can only be at the joints and are not likely to suddenly happen unles somehow interfered with. Such a unit should have a very long life.
All fridge units like to be run regularly to get the oil contained within the circuit to the seals so they do not dry out and wear. (Particularly important on car ac units which should be run at least wekly for along life.)

 

[Pete735]

I think there is some confusion here. Vehicle a/c systems have seals or more precisely o rings. If system is not run regularly (10 mins a week is enough) then these seals dry out and contract. Refrigerant leakage then occurs. O rings are used to join pipes as they have some "give" in them and there is a lot of vibration under a car bonnet, especially with diesel cars.

Fridges cannot travel under their own steam so do not need flexible joints, they have hard or solid joints - typically brazed . So you do not need to worry about running a fridge every week.

Yes, refrigerants did change for cars in the early 90's. R12 did have a larger molecule than the current R134a. R12 is an ozone depleter so was banned. The current refrigerant R134a is not so effective in an R12 designed system- but there are virtually no R12 systems around now.

Hermetically sealed danfoss compressors are more efficient than 10 years ago (as they will be in 10 years time no doubt) and if looked after will run for years without trouble. Where it can be a problem is if leaks are not fixed and a fridge is frequently regassed then compressor failure can follow as everytime refrigerant escapes a small quantity of compressor oil will go with it. Eventually it will overheat and seize.

I hope the above helps to put things in perspective.

 

[Norman_E]

Obviously, and as others have said, you need to get any leaks fixed, and the unit fully gassed, but there is another reason why some fridges never seem to get cold enough.

What a fridge is actually doing is pumping heat out of the interior, and dispersing it outside. To work properly the fridge needs to be able to get rid of the heat it generates as well as the heat it pumps out. If the motor, compressor and evaporator are enclosed so that the airflow over them is poor you are unlikely to get efficient cooling. Sometimes a little fan arranged to blow air over the evaporator will turn a marginal fridge into an acceptable one.

 

[TonyS]

Hi Steve,
I rang Waeco who gave me some names but these are listed on their site under Hampshire. I got an offer from Simon Ford of NF Refrigeration who was helpful but busy. However, the first I rang and was recommended on my previous post, reporting the problem, was Penguin Refrigeration. Their roving agent is Rob Wells. He knew the problem, it is common on Waeco units, and had the whole thing fixed in 5 minutes. He took rather longer to test the thermostat and fix the fan that was noisy. Both quoted under £100. The kit required is a small cylinder of gas (about a foot long and 3 inch dia) and a manifold with a couple of gauges. Penguin have a resident refrigeration engineer at Hamble Point Marina.
Have you tightened your couplers?
When are you leaving for South Brittany?
Best wishes,

 

[Bav34]

Thanks for the info. Tony.

We'll go south when (if) the weather settles. Such a rubbish year last year that we came back after 10 weeks instead of 5 months /forums/images/graemlins/frown.gif

If you remember our prop fell off in The Morbihan because the fridge needed re-gassing /forums/images/graemlins/ooo.gif /forums/images/graemlins/ooo.gif /forums/images/graemlins/ooo.gif /forums/images/graemlins/ooo.gif /forums/images/graemlins/ooo.gif