3way fridge thermal gel replacement ? (1 Viewer)

[Chris+Tracy]

Hi Chris,
I did exactly the same as you, even letting the fin plate slip in the freezer compartment. I don't think it matters as i am now getting -20°C in the freezer and 3°C in the fridge, although it does depend where you place the temp sensor and i have 1 small fridge fan.

 

[Mr Chrysalis]

Not sure it has solved the problem as the fridge is only around 6. But it is completely empty which is never a good test, and every time I open the door of course I lose all the cold air
I’m filling it up with a dozen cans of beer to see if that helps, but I’ve ordered some more paste as I may have wiped more off when the plate slipped

 

[WESTY66]

Not sure it has solved the problem as the fridge is only around 6. But it is completely empty which is never a good test, and every time I open the door of course I lose all the cold air
I’m filling it up with a dozen cans of beer to see if that helps, but I’ve ordered some more paste as I may have wiped more off when the plate slipped

Oh dear, that doesn’t inspire my ability to do the same job tomorrow, I think ill
Make a mess of it and it would be worse than it is now

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[Mr Chrysalis]

I’ve been keeping the fridge under test following my thermal grease addition at the weekend. The temperature is good on some levels but very variable across the fridge, so I am experimenting with a small internal circulation fan. Overnight I got a pretty steady 2-3 degrees with the fridge set on electric 5 bars ( full on). I’m using full beer cans and bottles to give the inside some heat capacity and I’ve just turned it down to 4, so I’ll see how it gets on today. I think this shows that the thermal grease replacement has worked but that circulation is the real issue

That wire comes out through the door seal and plugs into the socket designed for the TV, I don’t really want to drill a hole through the back of the fridge if it becomes a permanent fixture!

 

[Charlie57]

Try spreading those bottles on the bottom shelf, a full shelf results in blocking air flow

 

[Hettie's Crew]

Two on Tour
Can I ask, do you have the baffle in your gas flue/chimney as well as your extension mod.
I’ve just put a baffle in our Dometic RMDT8505 flue after I cleaned it and discovered it didn’t have one, though I’ve not tried it yet to see if it’s better.

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[Mr Chrysalis]

Try spreading those bottles on the bottom shelf, a full shelf results in blocking air flow

I see where you are coming from but the worst circulation and highest temps I got were in an empty fridge. The row of cans on the top shelf are effectively increasing the size of the aluminium heat sink. The ones at the bottom are effectively providing heat capacity , helping to cook air entering when the door is open and effectively reducing the volume of air to cool. If I spaced them out, they would roll back and forth in transit, so I would need to spread them apart with small packs of butter or cheese!

 

[Two on Tour]

Two on Tour
Can I ask, do you have the baffle in your gas flue/chimney as well as your extension mod.
I’ve just put a baffle in our Dometic RMDT8505 flue after I cleaned it and discovered it didn’t have one, though I’ve not tried it yet to see if it’s better.

Yes, I kept the the baffle as I I'm trying to retain the heat in the chimney longer for it to be transferred to the boiler section of the system.

 

[Hettie's Crew]

Yes, I kept the the baffle as I I'm trying to retain the heat in the chimney longer for it to be transferred to the boiler section of the system.

Thanks, I might give it a go, what’s the internal diameter of the tube you used, it’ll save me scuffing my forearms and scraping my knuckles to get in there again to measure it.

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[Two on Tour]

What’s the internal diameter of the tube you used, it’ll save me scuffing my forearms and scraping my knuckles to get in there again to measure it.

Not off the top of my head and we are on the road in Italy at present.
I found the size by trial and error by offering up verious off cuts of ally tube I have knocking about. I can tell you when we are back home in a weeks time.

 

[Two on Tour]

Thanks, I might give it a go, what’s the internal diameter of the tube you used, it’ll save me scuffing my forearms and scraping my knuckles to get in there again to measure it.

Hettie's Crew, the internal diameter required is 21mm, so 25mm aluminium tube with a 2mm wall thickness should do the job.

Available from this seller on the drop-down list.

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[gwyntaxi]

Finally my Thermal grease has arrived from China... £1.30 for 30gm tubes, bought 2 just in case.

Just done mine, used 1 tube. Old stuff was quite dried on so scraped it all off and put on new..
Fridge now hooked up to the gas and lets see how it goes..

Pics attached if they help anyone to understand it more..



View attachment 420269View attachment 420270View attachment 420271View attachment 420272View attachment 420273View attachment 420274View attachment 420275

Thanks Tonka really useful photos.

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[Lenny HB]

I took my wire out through the hole the sensor cable goes through.
I did my tests with plastic containers in the fridge, I've found in use it runs a bit warmer but we always have our fridge crammed full.
One of the biggest differences I found was the time the fridge tales to recover after opening the door, about 20min compared to an hour without the fan.
If does use more gas a small price for cold beer.

Lenny's Modding the new Gin Palace

@Lenny HB how's the fridge fan modification performing, especially inconsideration of the higher French temps your are currently experiencing? Sorry missed your post, when we were in France it was 31, with the fans ruinning performance was just about acceptable, 8 deg at the bottom 4 at the top...

www.motorhomefun.co.uk

 

[Mr Chrysalis]

I’ve been keeping the fridge under test following my thermal grease addition at the weekend. The temperature is good on some levels but very variable across the fridge, so I am experimenting with a small internal circulation fan. Overnight I got a pretty steady 2-3 degrees with the fridge set on electric 5 bars ( full on). I’m using full beer cans and bottles to give the inside some heat capacity and I’ve just turned it down to 4, so I’ll see how it gets on today. I think this shows that the thermal grease replacement has worked but that circulation is the real issue
View attachment 781244View attachment 781245
That wire comes out through the door seal and plugs into the socket designed for the TV, I don’t really want to drill a hole through the back of the fridge if it becomes a permanent fixture!

When I did this before, the finned plate slipped whilst I was putting it back so I was concerned that I might have scraped the grease off. We used it at Pickering and Malton and it was OK, but a bit high, around 6 deg.
So at the weekend I did the job again. This time I wedged some timber immediately under the plate ( supported by the drip tray) so that when I put it back, it could not slip down. Also I tried a magnetic screwdriver, which did not work as the screws are alloy/ ss but not magnetic, but a blob of blue tack held them on the screwdriver tip ok.
I did not scrape off the paste that I had put on a few weeks ago, as it was still in the right place but spread about 5-10 mm above the pipe as well. I added. 2 more tube fulls of the same paste , making it 4 tubes in total, then reassembled it. Much easier with the timber wedge and the Blu-ray.
I cooked it on gas yesterday ( the only contents are about 8 bottles of beer and 2 frozen dog foods) then turned it to 240v overnight and monitored it for 24hrs

With the fridge set at 4 bars ( 5 is the max) I achieved a max of 4 and a min of 2 in the fridge, and -9 to -16 in the freezer.
Dead chuffed with that!

 

[JockandRita]

Nice one Chris.

Our older rotary style controller is set between a third and half way, and we are getting a reading of 5° - 6°C, which is ideal for Rita's meds............and my beer when the cool box isn't on.

I never tested the freezer temperatures when I last did the job, as the freezer always seemed to work fine, and still does. It was the fridge temperatures which really mattered, and the difference after the paste replacement, was immediately noticeable for the better.

BTW, when transporting chilled and frozen foods, the temperatures are normally 5°C and -25°C respectively.

Cheers,

Jock.

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[Mr Chrysalis]

Nice one Chris.

Our older rotary style controller is set between a third and half way, and we are getting a reading of 5° - 6°C, which is ideal for Rita's meds............and my beer when the cool box isn't on.

I never tested the freezer temperatures when I last did the job, as the freezer always seemed to work fine, and still does. It was the fridge temperatures which really mattered, and the difference after the paste replacement, was immediately noticeable for the better.

BTW, when transporting chilled and frozen foods, the temperatures are normally 5°C and -25°C respectively.

Cheers,

Jock.

I assume that is in 12V when transporting Jock ? -25 is excellent

 

[JockandRita]

I assume that is in 12V when transporting Jock ? -25 is excellent

I meant commercially Chris.

Cheers,

Jock.

 

[Mr Chrysalis]

I meant commercially Chris.

Cheers,

Jock.

Oh sorreee! I thought you meant in your MoHo

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[Toskana75]

The stuff is designed to bridge microscopic gaps between two flat surfaces clamped together. It enables heat transfer where the two surfaces don't actually touch. In our application the gaps are neither microscopic nor between flat surfaces. However the principle is the same: wherever the two surfaces (the finned heatsink and the pipe mounting) are designed to make contact a film of thermal paste, thick enough to bridge any gaps, should be applied. Too much does no harm other than wasting whatever is squeezed out when the heatsink mounting screws are tightened.

I wouldn’t say that this is liberal, surely your only point of contact of a flat surface on round one would be minimal. So the job of the compound is to increase the surface contact and increase the thermo transfe. So you’d want enough Togo round half the pipe. ?

 

[Toskana75]

Maybe this will help answer some confusion or miss information.
My concerns with using the wrong mastic is it may dry up through time and become in affective, and the stuff used computer CPU’s is usually between to flat surface with very little surface area exposed to the air.

 

[tonyidle]

I wouldn’t say that this is liberal, surely your only point of contact of a flat surface on round one would be minimal. So the job of the compound is to increase the surface contact and increase the thermo transfe. So you’d want enough Togo round half the pipe. ?



View attachment 875694

The pipe in question has a "flat" plate welded to it to which the finned casting attaches.

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[Lenny HB]

The pipe in question has a "flat" plate welded to it to which the finned casting attaches.

Never seen one like that, on all the Dometic ones I've seen it's just a round pipe.

 

[tonyidle]

Never seen one like that, on all the Dometic ones I've seen it's just a round pipe.

I've only done a couple. How are the fins attached to a round pipe?

 

[Lenny HB]

I've only done a couple. How are the fins attached to a round pipe?

They don't attach they just rest against the pipe.

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[tonyidle]

They don't attach they just rest against the pipe.

It's a long time since I did the two. They were small caravan fridges and both had a crudely welded and not very flat plates on the pipe.

 

[Lenny HB]

It's a long time since I did the two. They were small caravan fridges and both had a crudely welded and not very flat plates on the pipe.

 

[tonyidle]

View attachment 876093

I'm not surprised that decent heat sink compound makes a real difference!

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[Lenny HB]

I'm not surprised that decent heat sink compound makes a real difference!

That was just after I took the heat sink off the crap stuff Dometic use, it goes hard after 2 or 3 years and then doesn't transfer heat. That photo is deceptive it was quite hard.

 

[Toskana75]

The pipe in question has a "flat" plate welded to it to which the finned casting attaches.

Not on my Dometic fridge or others pictured in this post? The only flat bits are some lugs for the screws to attach. The major contact is round pipe on flat plate and that’s where the Thermal mastic is applied.

 

[tonyidle]

Not on my Dometic fridge or others pictured in this post? The only flat bits are some lugs for the screws to attach. The major contact is round pipe on flat plate and that’s where the Thermal mastic is applied.

Agreed. The ones I did were small caravan fridges in the early '90s.

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