Poor Fridge Performance

[bigtwin]

Do the aluminum fins inside ice up, or just condensate?

There is a small amount of ice at the top left but it’s mainly condensate.

What is the ambient temperature?

Currently it’s high (28.9 inside) but I’ve been monitoring it over the past week when temperatures have been lower.

Internal temperatures are no better first thing in the morning when it’s cooler and been running all night.

Ian

 

[bigtwin]

Ok, I’ve been running a USB fan inside the fridge for more than 24hrs with no discernible effect on temperatures.

I’ve also taken some temperature readings (with a laser/infrared gun) both inside and around the fridge door with the following results:

Ambient - 28.9

Freezer Door Outside (checking for seal leaks):
Top 29.2
LHS 26.2
RHS 25
Bottom 22.9

Freezer Inside:
Fins -20.5
floor -15
LHS Wall -10.8
RHS Wall -9.2

Fridge Door Outside:
Top 27.4
LHS Top 25.6
LHS Middle 25.9
LHS bottom 25.1
RHS Top 23.7
RHS Middle 23.9
RHS bottom 24.3
Bottom 22.2

Fridge Inside
fins 6.2
floor 8.8
LHS Wall 9.3
RHS Wall 6.7

Clearly, the refrigeration cct is working as evidenced by the freezer temperatures.
However, equally clearly, the effectiveness of heat transfer in the fridge is degraded. This all points to the heat transfer between the fins and the refrigeration pipe work but, given that I’ve replaced the thermal paste it’s a mystery!

While The readings around the door show a temperature gradient (this is to be expected) the difference (5°C) doesn’t suggest to me that the seals are defective.



Ian

 

[Coastal Cruiser.]

That’s very extreme

Yes that’s why if I buy a new one I am going Stealth nobody will know it’s me if I buy a Carthargo people will drive/walk the other way to avoid me,could be a plan

 

[Richard n Ann]

There is a small amount of ice at the top left but it’s mainly condensate.

Currently it’s high (28.9 inside) but I’ve been monitoring it over the past week when temperatures have been lower.

Internal temperatures are no better first thing in the morning when it’s cooler and been running all night.

Ian

Take the aluminum fins off the fridge and see if the evaporator pipe behind will frost up in an unloaded state. It should be a very hard frost you can't scratch off with your finger nail

 

[bigtwin]

Take the aluminum fins off the fridge and see if the evaporator pipe behind will frost up in an unloaded state. It should be a very hard frost you can't scratch off with your finger nail

There’s ice on the freezer fins and It’s a single refrigeration circuit so no reason to doubt the refrigeration circuit.

I’m a little loathe to take the fins of the fridge again having just replaced the thermal paste.

If I get sufficiently exasperated I might try your suggestion.

Nobody has yet answered this question that I put in my OP:

Would too much, as well as too little, paste be detrimental to performance?

Ian

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[rosalan]

Too much paste will NOT work, I know, I tried and the cold gets lost in the paste. Only the finest layer works. The freezer pipe should be clean before applying the paste. Last year mine was not working too well and I tried tightening the screws on the fins and luck was with me, it worked again.

 

[Richard n Ann]

There’s ice on the freezer fins and It’s a single refrigeration circuit so no reason to doubt the refrigeration circuit.

I’m a little loathe to take the fins of the fridge again having just replaced the thermal paste.

If I get sufficiently exasperated I might try your suggestion.

Nobody has yet answered this question that I put in my OP:


Ian

I put lots on mine and it fixed the problem, the extra is just wasted I suppose but it worked for mine

 

[Richard n Ann]

There’s ice on the freezer fins and It’s a single refrigeration circuit so no reason to doubt the refrigeration circuit.

Has it suddenly stopped working or has it been getting worse gradually? It could be a small refrigerant leak, still enough in it for the freezer but by the time it gets to the fridge evaporator there's no liquid left. That's why I suggested taking the aluminum fins off, if there's no frost it's probably scrap

 

[Flairy]

Very close to your home there’s motortech Dometic fridge repairs he’s very knowledgeable 07528 784180he might have the answer he was very helpfull on the phone to me.

 

[Cush]

Nobody has yet answered this question that I put in my OP:


Ian

Are you by any chance accidentally ignoring rosalan , post #7

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[bigtwin]

Are you by any chance accidentally ignoring rosalan , post #7

Oops. I did ‘Like’ the post but must have forgotten about it.

Ian

 

[Wee Bold Davy]

I came across this video a while ago, some may find it useful. He's an Aussie who regularly has to deal with 40+ degrees

 

[Cush]

I came across this video a while ago, some may find it useful. He's an Aussie who regularly has to deal with 40+ degrees

I’m sharing that with my copilot! And will be testing her on it

 

[Googlebot]

If it helps, we have an RMDT 8505 and in the hot weather this week it has been awful!

I don’t think I helped by pitching on the slant and we had just done a big shop and filled it. It was however 15 degrees in the fridge and the freezer was about 2 degrees. Better now ambient temp has dropped again.

I would change it to a compressor model if I had £2500 spare.

 

[Sedge5]

Wrong thread!

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[Two on Tour]

We’ve been to a sculpture exhibition at Doddington Hall and Gardens today

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I know that you get thread creep, but this one is maybe more than a bit off the thread subject.

 

[1967bowesj]

If it helps, we have an RMDT 8505 and in the hot weather this week it has been awful!

I don’t think I helped by pitching on the slant and we had just done a big shop and filled it. It was however 15 degrees in the fridge and the freezer was about 2 degrees. Better now ambient temp has dropped again.

I would change it to a compressor model if I had £2500 spare.

We found the same in France last year, on a slope and fridge throws a wobbly
New compressor one ain’t dometic or thetford but it was not £2500

 

[Sedge5]

I know that you get thread creep, but this one is maybe more than a bit of the thread subject.

Ooops . . . apologies!

 

[bigtwin]

It could be a small refrigerant leak, still enough in it for the freezer but by the time it gets to the fridge evaporator there's no liquid left. That's why I suggested taking the aluminum fins off, if there's no frost it's probably scrap

I do now have ice forming along the top half of the fins but the internal temperature has only gone as low as 5°C. I shall have to see how we get on at Malvern this weekend.

Very close to your home there’s motortech Dometic fridge repairs he’s very knowledgeable 07528 784180he might have the answer he was very helpfull on the phone to me.

I had a chat with Ian and, based on the symptoms he thought that it was probably the thermistor (temperature sensor) that had failed.

Initially, I thought that made sense but thinking about it further I’m less sure for two reasons:

1. the cooling circuit is working (it must be being demanded by the thermistor) as the freezer is well frozen.
2. the manual suggests that a thermistor failure would be indicated on the display panel.

It may be that, having replaced the thermal paste, I’m expecting too much from the fridge. Anyway, we’ll see how we get on at Malvern this weekend.

Thanks to all who have chipped in, it is appreciated.

Ian

 

[Richard n Ann]

I do now have ice forming along the top half of the fins but the internal temperature has only gone as low as 5°C. I shall have to see how we get on at Malvern this weekend.

It's not doing too bad at that then. My 3 way fridge was a rare good one and even sometimes froze things, but lots of people say they're useless

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[Barriesimpson]

I came across this video a while ago, some may find it useful. He's an Aussie who regularly has to deal with 40+ degrees

Excellent video, thanks for sharing.

 

[DavidG58]

5C is a good beer temp

 

[Barriesimpson]

5C is a good beer temp

But 3ºC is better

 

[bigtwin]

But 3ºC is better

That’s for lager, we’re discussing beer!

Ian

 

[Barriesimpson]

That’s for lager, we’re discussing beer!

Ian

Sorry, my bad

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[rosalan]

I am sorry if replacing thermal paste has not worked but unless the freezing pipe behind the fins is not cold, it more or less has to be the physical cold pipe is not touching the alloy fins. That is what makes the fridge cold, if the freezing pipe is making the freezer cold.

 

[OldAgeTravellers]

There’s ice on the freezer fins and It’s a single refrigeration circuit so no reason to doubt the refrigeration circuit.

I’m a little loathe to take the fins of the fridge again having just replaced the thermal paste.

If I get sufficiently exasperated I might try your suggestion.

Nobody has yet answered this question that I put in my OP:


Ian

I think your only solution will be to take the fins off again, carefully and recover the peste as it probably hasn’t dried out yet. As you say the freezer is working so the fridge should as the fridge controls the freezer.
I suspect you have some debris between the cooling pipes and the fins so you are getting a bad heat transfer. Or your screws are not tight enough. There must be something holding the fins away from the pipes. No other explanation.

 

[bigtwin]

I am sorry if replacing thermal paste has not worked but unless the freezing pipe behind the fins is not cold, it more or less has to be the physical cold pipe is not touching the alloy fins. That is what makes the fridge cold, if the freezing pipe is making the freezer cold.

The fins are screwed fully onto the pipework but I can double check that they are really tight.

Ian

 

[Googlebot]

Just checked ours again, I have decided it is simply that it can’t cope with high ambient temps.

As soon as the internal temperature goes down to about 23 degrees, fridge is back to normal. Any hotter and it rises inside.

I didn’t help with pitching wonky.

All seems fine now it’s raining and cooler.

 

[bigtwin]

I suspect you have some debris between the cooling pipes and the fins so you are getting a bad heat transfer.

I fully cleaned the pipe before applying the paste.

Or your screws are not tight enough.

I tightened the screws reasonably tight but will check them again.

The heat transfer appears to be working as there is ice forming on the fins so the contact must be reasonably good.

Ian

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