New fridge freezing pipe to fridge

[tawhiri]

My fridge stopped working this year and I had a company take a look at it.
After a couple of visits to the boat they replaced the compressor and the evavorator plate in the fridge.

I had it running over night, and the contents of the fridge is now 12 degrees. However the theromstat did not kick in at any time, even though I had it set to 50%, but the pipe from the compressor is a frozen ice block 30cm before it enters the coolbox.

I have now reduced the theromstat to 30% and the compressor did switch off for a minuet before starting up again.

Is it normal that the pipe before entering the coolbox should freeze to an ice block.

By the way, the boat is in Croatia so ambient temperature is over 30 degrees.

Thanks Andrew

 

[RichardS]

The pipe will normally freeze on the outside. Mine always did in Croatia where there was no insulation and where the fridge is working hard so I bought foam some pipe insulation in B & Q and covered over the missing sections, although mine is a freezer and fridge so runs below zero.

Richard

 

[Yngmar]

Sounds like the system was overcharged with refrigerant and isn't working efficiently because of it. For more information, read here: http://coxeng.co.uk/heating-and-refrigeration/recharging-marine-refrigeration-systems/

If you're still in the area, the company that installed it should be able to remove some refrigerant in a eco-friendly fashion. If not, see section 3 in the above link.

 

[<152587>]

Air in refrigerant?

 

[Heckler]

My fridge stopped working this year and I had a company take a look at it.
After a couple of visits to the boat they replaced the compressor and the evavorator plate in the fridge.

I had it running over night, and the contents of the fridge is now 12 degrees. However the theromstat did not kick in at any time, even though I had it set to 50%, but the pipe from the compressor is a frozen ice block 30cm before it enters the coolbox.

I have now reduced the theromstat to 30% and the compressor did switch off for a minuet before starting up again.

Is it normal that the pipe before entering the coolbox should freeze to an ice block.

By the way, the boat is in Croatia so ambient temperature is over 30 degrees.

Thanks Andrew

Is it the pipe FROM the evaporator BACK to the compressor? If so, then the system is overcharged. What is happening is that the liquid gas is too much, and not all evaporating in the evaporator. It is continuing to evaporate in the pipe back to the compressor. In a worst case scenario, as the temp drops in the box then you will get the frost line going back to the compressor and liquid gas entering the compressor on the suction side. Not good!
If it is on the pipe GOING to the evaporator then you have a problem with a blockage in the pipe to the evaporator and the gas is evaporating at the blockage before it hits the evaporator, very unlikely by the way.
By the way, a very simplistic way of explaining, there are a lot of pedants on here!

 

[<152587>]

Is it the pipe FROM the evaporator BACK to the compressor? If so, then the system is overcharged. What is happening is that the liquid gas is too much, and not all evaporating in the evaporator. It is continuing to evaporate in the pipe back to the compressor. In a worst case scenario, as the temp drops in the box then you will get the frost line going back to the compressor and liquid gas entering the compressor on the suction side. Not good!
If it is on the pipe GOING to the evaporator then you have a problem with a blockage in the pipe to the evaporator and the gas is evaporating at the blockage before it hits the evaporator, very unlikely by the way.
By the way, a very simplistic way of explaining, there are a lot of pedants on here!

Which made me suggest air/moisture in the system, the moisture freezes in the expansion valve causing a blockage.

 

[Heckler]

Which made me suggest air/moisture in the system, the moisture freezes in the expansion valve causing a blockage.

In most of our systems we dont have an expansion valve, just a capillary tube which acts as a restrictor, liquid on one side and it starts to expand in to gas on the other side. Normally, if moisture is present, then it usually freezes there and blocks the capillary tube (hence Vics post for a timer elsewhere) You didnt mention moisture by the way, just air. Air causes its own problems. Mostly high condensor pressure, see here https://www.achrnews.com/articles/83925-get-the-air-out-of-that-refrigeration-system

 

[superheat6k]

What refrigerant ?

Is there an ice build up on the evaporator plate inside the fridge too ?

 

[Pasarell]

I had a similar problem on my new (to me) boat last year. Engineer checked pressure and said it was overgassed. Let some out and it has all been good since then. Total time on site for the engineer was about 15 minutes!

 

[sailaboutvic]

In most of our systems we dont have an expansion valve, just a capillary tube which acts as a restrictor, liquid on one side and it starts to expand in to gas on the other side. Normally, if moisture is present, then it usually freezes there and blocks the capillary tube (hence Vics post for a timer elsewhere) You didnt mention moisture by the way, just air. Air causes its own problems. Mostly high condensor pressure, see here https://www.achrnews.com/articles/83925-get-the-air-out-of-that-refrigeration-system

Hi Stu
The problem with mine is mosture , I know that , as when I heat up the plate it all works again , I found last year the timer stop this happen , but taken note of the last engineer who I ask to vacuum it ( no point in asking for advise then not taken it ) I removed it , now off cas it happen again and the timer has stop working .
Any way back to problem , I read a good article by a well know fridge AC guy , and it says deep vacuum a lone it no guarantee, and to fit a filter dryer , which now I think I do .
That's not to say the op has the same problem

 

[sailaboutvic]

Which made me suggest air/moisture in the system, the moisture freezes in the expansion valve causing a blockage.

I no expert as I wouldn't be asking for help with mine else where ,
but it seen it don't have to be a leak , the DB35/50 compressor which most of us got all have a small amount of oil in them ( no matter what anyone says here ) and the smaller amount of mosture will at some point collet with the oil and cause a blockage , ( this is why works fine once I put heat to it ) this as also been confirmed by danfoss and the way to stop this happening is to fit a filter dryer , what get me is why don't their fit filter dryer as a standred part on these thing in the first places if they know there going to be a problem at some point , by the way all domestic fridges have them it seems

 

[<152587>]

In most of our systems we dont have an expansion valve, just a capillary tube which acts as a restrictor, liquid on one side and it starts to expand in to gas on the other side. Normally, if moisture is present, then it usually freezes there and blocks the capillary tube (hence Vics post for a timer elsewhere) You didnt mention moisture by the way, just air. Air causes its own problems. Mostly high condensor pressure, see here https://www.achrnews.com/articles/83925-get-the-air-out-of-that-refrigeration-system

But does not air contain moisture? I take your point as to the capillary tube, but it still acts as to allow expansion,

The whole point as to a small amount of air left in the system due to possibly not a thorough evacuation prior to re-charging.

 

[macd]

The whole point as to a small amount of air left in the system due to possibly not a thorough evacuation prior to re-charging.

Whenever I've seen a boat fridge recharged (always in Med waters), I've never observed any attempt at evacuation, nor even the means to do so. Of course it's routine with cars, but then with them you don't have to lug the kit aboard and down a companionway.

 

[<152587>]

I no expert as I wouldn't be asking for help with mine else where ,
but it seen it don't have to be a leak , the DB35/50 compressor which most of us got all have a small amount of oil in them ( no matter what anyone says here ) and the smaller amount of mosture will at some point collet with the oil and cause a blockage , ( this is why works fine once I put heat to it ) this as also been confirmed by danfoss and the way to stop this happening is to fit a filter dryer , what get me is why don't their fit filter dryer as a standred part on these thing in the first places if they know there going to be a problem at some point , by the way all domestic fridges have them it seems

One of the first tools in a good fridgies tool bag is to look for the wet patch, oil is carried around the system in gas and exudes with the gas in the area of the leak. Years ago we used old fridge compressors in an attempt to spray paint small motor bike parts, it was always a problem to keep the air oil free.

Guess it is all down to competitive pricing, a bit like wind gennys. That will e £xxx for the genny, oh you will need this regulator at £xxx to prevent the batts frying.

 

[<152587>]

Whenever I've seen a boat fridge recharged (always in Med waters), I've never observed any attempt at evacuation, nor even the means to do so. Of course it's routine with cars, but then with them you don't have to lug the kit aboard and down a companionway.

Not only with cars, when we were doing chilled water systems on ships the vac pump would be running for a couple of days.

 

[PaulJS]

Years ago when I was at college a somewhat crusty Marine Engineering lecturer said "There's two types of contamination in a fridge system, one's inescapable -oil - and the other's f******g unforgivable - water".
We did ask about air, but he said that unless it was in massive quantity, it was the moisture introduced with it was what would cause problems...

 

[sailaboutvic]

One of the first tools in a good fridgies tool bag is to look for the wet patch, oil is carried around the system in gas and exudes with the gas in the area of the leak. Years ago we used old fridge compressors in an attempt to spray paint small motor bike parts, it was always a problem to keep the air oil free.

Guess it is all down to competitive pricing, a bit like wind gennys. That will e £xxx for the genny, oh you will need this regulator at £xxx to prevent the batts frying.

Mine don't have a leak for sure , both times I have mine check the gas as never been low , no damp patch , no sign of any thing .
what happen is the oil (POE) which are in all BD compressor pick up little part of moncue of water ,
, even dirt over the years and this is where the blockage happen , this as been confirm by danfoss them self so it not always leaks that cause the problem ,
Like mine it's been vacuumed twice now over the last year both time I been told that all it needed of cause as time as shown that's not the case , now I going to ininsis to have a filter dryer fitted this time and if the engineer who come out this time tell me other wise I just tell him to forget . I can get it working myself for nothing .
The real problem with us liveaboard is we always on the move so you just can't call th same guy out , it just pay pay pay .

 

[<152587>]

Years ago when I was at college a somewhat crusty Marine Engineering lecturer said "There's two types of contamination in a fridge system, one's inescapable -oil - and the other's f******g unforgivable - water".
We did ask about air, but he said that unless it was in massive quantity, it was the moisture introduced with it was what would cause problems...

Which it is essential to vac the system, moisture boils off at low temp in a vacuum.

 

[owen-cox]

This fridge the OP is talking about is 99% sure an overcharged system. This often happens if the engineer doesnt stay on board after recharging to see it cut off on the thermostat and get fully down to temperature. This is why when i work on small fridges I like to do the job then come back the next day after having it run all night to check they still work and are correctly charged.
The issue with moisture is that if nobody has connected gauges to the system there is no way any moisture can get in the system. With small danfoss compressor systems they often have quick fit connectors for self installation of the components. Unfortunately they all leak. If they are inbthe siction side of a system they often end up in negative pressure and so suck air( and moisture) into the system and cause freezing issues at the evaporator end of the capillary tube. The only way to solve this is to vacuum the system out and while most systems have a filter drier installed just before the capillary they are a very small volume and will only take ancertain amount of moisture out of the system before they become saturated.

Vacuuming of the system should only be carried out with a sensitive vacuum gauge fitted which will allow the engineer to see exactly when the moisture content is down to the required amount. This indicates when boiling of moisture has completed and there is no more moisture present. Around 500 mocrons is the minimum vacuum a system a system should be taken down to. This can take 12 hours wven on a very small boat fridge due to the hygroscopic oils used for lubrication.

 

[tawhiri]

I also suspect it is over charge with gas. The company asked me to make a photo of the ice and send it to them.
I will do this tomorrow when the solar panels are charging.
Even when the thermostat is turned down to 30% there is some ice on the pipe. The plate is only frosty with a littly ice but not much.