Fridge cooling issue

[Caladh]

With a partially freezing Frigoboat letterbox I found this video. I tried the solution and amazingly it seems to have worked. Can anyone ascertain why this works and for how long it might continue to do so? Also assuming no leaks I’m guessing I’ll need a purge at some point.
https://www.google.com/url?sa=t&rct...usg=AOvVaw3AsYD3YIcomu6WI5gJ0LTl&opi=89978449

 

[Refueler]

Interesting ... but cannot help but consider the increased amps shown after the pot of hot water is put in - may be simply the increased cooling action needed ?

At the end of the vid - the door of the fridge is seen to be loose and unreliable ... mmmm

But you say it worked for you .. interesting ...

 

[vas]

bolleaux (imho)
he may be right in that particles do clog the system, hence why you have a filter somewhere in the circuit, look for a finger sized barrel somewhere at the back.
I'd wait for one of the knowledgeable lot of the forum to comment, but what he says and does overall don't really make sense.
not sure how a fridge that flow is compromised stops pumping (or rather trying to), maybe there's a way.

In my case and for 40euro (iirc) took the fridge to proper fridge mechanics after spending a few months trying to persuade them to work on it (were too busy with real work to deal with a game fridge - their words!) who removed the freon, replaced the filter with a larger one, vacuumed and refilled. Works fine now for 2-3yrs.
V.

 

[Caladh]

Interesting ... but cannot help but consider the increased amps shown after the pot of hot water is put in - may be simply the increased cooling action needed ?

At the end of the vid - the door of the fridge is seen to be loose and unreliable ... mmmm

But you say it worked for you .. interesting ...

Yes - I was surprised myself. I’ll leave it on for a few days to see if it stays frozen. I posted because I’m interested in the theory of why it might have worked?

 

[lustyd]

he may be right in that particles do clog the system, hence why you have a filter somewhere in the circuit, look for a finger sized barrel somewhere at the back.

*not an expert but spent a long while investigating last year*

The filter is a dessicant to remove moisture, and this issue is probably that moisture in there freezing as ice preventing gas flow. Melt the ice and the issue clears temporarily. Likely cause is a bodged re-gas where someone just pumped more juice in without pulling a vacuum. I suspect the more permanent fix is to replace that filter, pull a vacuum for long enough to fully evacuate all the moisture and gas, and then refill with good gas.

Worth noting that most of the world will no longer just sell you the gas, and regs now require capturing the stuff you suck out with a more sophisticated vacuum pump. As such it's usually now easier to get a pro to do this. It's probably cheaper to buy a new unit, but those may develop a leak anyway due to the way they connect.

 

[Boater Sam]

Snake oil of the best kind. A waste of water and gas.

 

[vas]

*not an expert but spent a long while investigating last year*

The filter is a dessicant to remove moisture, and this issue is probably that moisture in there freezing as ice preventing gas flow. Melt the ice and the issue clears temporarily. Likely cause is a bodged re-gas where someone just pumped more juice in without pulling a vacuum. I suspect the more permanent fix is to replace that filter, pull a vacuum for long enough to fully evacuate all the moisture and gas, and then refill with good gas.

Worth noting that most of the world will no longer just sell you the gas, and regs now require capturing the stuff you suck out with a more sophisticated vacuum pump. As such it's usually now easier to get a pro to do this. It's probably cheaper to buy a new unit, but those may develop a leak anyway due to the way they connect.

agree, but otoh, same would work if you turned off the fridge for a whole morning or a day and fire it up again, everything will have melted and ready to freeze again
no need to boil water and anyway if it's the filter (or inefficiency of it!) then you'd need to thaw outside not in the evaporator...

 

[lustyd]

agree, but otoh, same would work if you turned off the fridge for a whole morning or a day and fire it up again, everything will have melted and ready to freeze again
no need to boil water and anyway if it's the filter (or inefficiency of it!) then you'd need to thaw outside not in the evaporator...

If you do that the food would be ruined, this way it's sorted quickly, but yes quite right it should also work.

The filter may well be saturated, leaving moisture to freeze and build up in the cold bit, hence this works. Really it's probably frozen at the end of the cappillary tube as it enters the evaporator but that would be more complex instructions for people who don't know how it works. If the filter is saturated the water will just keep doing this every now and then, there's nowhere else for moisture to go in a working system.

 

[superheat6k]

Haven't watched the video , but can likely explain how putting a pot of hot water on the condenser resolved the problem (very much short term BTW ! ).

Increasing the condenser temperature de facto increases the pressure within the condenser. This increases the pressure difference across the capillary tube that controls the flow of refrigerant from the high pressure (hot) side to the low pressure (cold) side. This in turn increases the flow of refrigerant and this in turn improves the cooling effect achieved.

But it will not cure the real problem, which is a shortage of refrigerant - likely a small leak somewhere, and until this is properly resolved neither will your base problem be resolved either.

 

[Refueler]

mmmm water .... filter (separator ?) seems logical

Its funny actually as my fridge on board is not freezing ... only dropping temp and pulling more amps than I expected. I was considering getting a gas recharge done ...

Might give it a try ...

 

[Caladh]

mmmm water .... filter (separator ?) seems logical

Its funny actually as my fridge on board is not freezing ... only dropping temp and pulling more amps than I expected. I was considering getting a gas recharge done ...

Might give it a try ...

Let us know if it worked for you too.

The fridge is still frozen today and I’ve turned it down a little. I’ll monitor to see if it eventually fails. Even if I have to do the necessary hot water trick every couple of months in season I can then save for a rare marine fridge engineer to attend!! FYI - this time last year a local engineer did attend, replaced seals in couplings, vacuumed out the system and re gassed. It was only when I started using the fridge in earnest did I discover the partial freezing issue - and I was in France by then. The hot water MUST do something because the fridge had been turned on and off many times before I tried this “fix” however temporary it might be.

 

[lustyd]

marine fridge engineer

Fridge engineers are just fridge engineers. Boat fridges are as simple as it gets provided there's reasonable access so don't feel you need a marine one. There's only maybe three things you'd do to fix a marine fridge - brazing and gassing, regassing, or replace the electronics box. Sometimes the blinkenlights break on the electronics and you can bypass the blue light, but really there's not a lot else in there.
If you get a re-gas just make sure the engineer asks what temperature you want to run at as this affects the pressure of gas.

 

[vas]

I remember them being impressed by how little freon the system needed (a typical 80lt fridge)
No idea how they figured it out though, wasn't by the amount they extracted as there were no connectors and they had to cut and braze pickup points, so all freon I assume was lost when cutting the pipework.

 

[Caladh]

Fridge engineers are just fridge engineers. Boat fridges are as simple as it gets provided there's reasonable access so don't feel you need a marine one. There's only maybe three things you'd do to fix a marine fridge - brazing and gassing, regassing, or replace the electronics box. Sometimes the blinkenlights break on the electronics and you can bypass the blue light, but really there's not a lot else in there.
If you get a re-gas just make sure the engineer asks what temperature you want to run at as this affects the pressure of gas.

How do I know what temperature I want to run at ???? it’s no.5 or 6 on my thermostat.

 

[lustyd]

How do I know what temperature I want to run at ???? it’s no.5 or 6 on my thermostat.

Relative to ambient temperature do you want a fridge or a freezer? Will you be sailing in Sweden or the Caribbean? Makes a difference to efficiency and the running of the system. To a good fridge engineer it's simple stuff but if they don't ask then maybe they don't know...

 

[Caladh]

Relative to ambient temperature do you want a fridge or a freezer? Will you be sailing in Sweden or the Caribbean? Makes a difference to efficiency and the running of the system. To a good fridge engineer it's simple stuff but if they don't ask then maybe they don't know...

I have a frigoboat letter box freezer. See my original post but thanks for the heads up.

 

[Caladh]

Fridge engineers are just fridge engineers. Boat fridges are as simple as it gets provided there's reasonable access so don't feel you need a marine one. There's only maybe three things you'd do to fix a marine fridge - brazing and gassing, regassing, or replace the electronics box. Sometimes the blinkenlights break on the electronics and you can bypass the blue light, but really there's not a lot else in there.
If you get a re-gas just make sure the engineer asks what temperature you want to run at as this affects the pressure of gas.

Tbh the last time a home fridge engineer visited my previous boat he was phased by the compressor and the correct bar to gas it to, and ended up over gassing it by a huge amount. Someone else (a marine fridge engineer) had to sort it out.

 

[Refueler]

Tbh the last time a home fridge engineer visited my previous boat he was phased by the compressor and the correct bar to gas it to, and ended up over gassing it by a huge amount. Someone else (a marine fridge engineer) had to sort it out.

Its not only boat fridges .. pal of mine had his Car AC regassed ... it then stopped working ... had to go to another service to have the pressure released back to correct - then AC worked perfect !

 

[superheat6k]

The possibility of moisture in the fridge system means someone has incorrectly attempted to fix the fridge previously, likely by not evacuating it properly. Any moisture (all air holds moisture) will freeze at the coldest position in the capillary tube, where it can build up as ice until the fine tube is almost completely blocked, but warming the condenser will not fix this. When it does melt the water will then circulate until it builds up again.

But this effect is less likely to affect capillary systems, but can affect systems with TEVvs, where the position of the high to low pressure drop is a specific and very tiny orifice.

 

[Caladh]

TEVvs ???