Fridge area developing freezing area of ice by fins

[PRW]

Recently the Thetford N3000 Fridge has started developing ice in the top right hand corner only though.
The campervan is level within 3 degrees. Fridge is working fine and is on EHU, just keeps developing this layer of ice. It's been removed a couple of times and keeps coming back.
Could it be the cooling fluid from behind the finds leaking? Or is it something else. Strange that it just appears in the top right corner and keeps coming back. If it was ice I can't understand where the moisture is coming from to keep forming the ice. Anyone seen this before?

 

[Figaro]

I don't think that is unusual, it is frozen moisture / condensation from the atmosphere in the fridge. I think the fridge does a cycle where it will defrost periodically, the ice melt and the water drain into an evaporation tank behind the fridge.
It may be iced only in one area as that is the coldest bit

 

[PRW]

I don't think that is unusual, it is frozen moisture / condensation from the atmosphere in the fridge. I think the fridge does a cycle where it will defrost periodically, the ice melt and the water drain into an evaporation tank behind the fridge.
It may be iced only in one area as that is the coldest bit

I agree it could also be moisture from the atmosphere in the fridge but why is this happening now as it's never happened before. Further, this has been going on for about 3 weeks now. Every time I remove the ice from the corner it reappears?

 

[EuroTrotters]

looks like insulation breakdown (moisture in the foam)

 

[Jev88]

Would a new layer of thermal paste help?

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[Figaro]

I agree it could also be moisture from the atmosphere in the fridge but why is this happening now as it's never happened before. Further, this has been going on for about 3 weeks now. Every time I remove the ice from the corner it reappears?

Maybe you've just never noticed before ?
Have a look below the fins and you should see a drain into the evaporation dish
It maybe your thermal paste has dried out and would benefit from being replaced to even out the cooling effect across the ali plate.
This is easy to do and lots of info on how if you do a search.
I doubt it's the refridgerant gas leaking

 

[PRW]

looks like insulation breakdown (moisture in the foam)

Not sure I follow. There's no insulation inside the fridge compartment.

 

[PRW]

Maybe you've just never noticed before ?
Have a look below the fins and you should see a drain into the evaporation dish
It maybe your thermal paste has dried out and would benefit from being replaced to even out the cooling effect across the ali plate.
This is easy to do and lots of info on how if you do a search.
I doubt it's the refridgerant gas leaking

OK, Thanks. It's possible I haven't noticed this before you're right but I'm not sure. I only discovered this when the milk in the fridge actually froze. I took everything out and defrosted the fridge. Since then it's not frozen anything in the fridge but this ice area has built up on the top RHS again. As you said I may have never noticed this before. Might contact Thetford support and see what they say but I'll also look into the Thermal paste option.

 

[EuroTrotters]

Not sure I follow. There's no insulation inside the fridge compartment.

The rear wall is insulated as are the top bottom and sides

 

[pagey]

I have a 3145 and it does the same

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[Diabalo]

It maybe getting too cold, outside vent covers are designed to stop it getting too cold.

 

[eurajohn]

It happens all the time, just that most people don't leave the fridge switched on for extended periods it won't show over a few days.

 

[eurajohn]

It maybe getting too cold, outside vent covers are designed to stop it getting too cold.

Vent covers are intended to be used when ambient temperatures are very low, absorption fridges need to be able to raise sufficient temperature in its operating system for them to work.
Also often recommended to cover vent grilles when washing the van.

 

[Stoosal]

Is your door seal, sealing properly? If it’s letting in warmer air from inside the motorhome it then condenses when it settles on the cold surface inside and eventually freezes. We keep the catch at the bottom of the door locked to keep the seal tight.

 

[PRW]

The rear wall is insulated as are the top bottom and sides

That's on the outside of the fridge though, not the inside.

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[PRW]

It maybe getting too cold, outside vent covers are designed to stop it getting too cold.

Outside vent covers have been on during this period.

 

[PRW]

Is your door seal, sealing properly? If it’s letting in warmer air from inside the motorhome it then condenses when it settles on the cold surface inside and eventually freezes. We keep the catch at the bottom of the door locked to keep the seal tight.

To my knowledge I would say Yes, but it's a good point and I'll double check.

 

[PRW]

It happens all the time, just that most people don't leave the fridge switched on for extended periods it won't show over a few days.

Interesting I didn't realise that. I've been on a site at the moment for a few weeks parked in same spot so could be just as you say.

 

[Wonders]

We had fridge freezing problem in our Thetford N150. If your problem persists it may be the thermister that needs replacing. Something like this.

SPARE N90 N97 N100 N104 N109 N112 N145 N150 THETFORD FRIDGE THERMISTOR 623077 | eBay

Product number 623077. N90, N97, N100, N104, N109, N112, N145, N150. Spare SR Thermistor for Thetford Fridges. Conversion Kits. Conversion Kits (48). All spare parts must be fitted by a qualified technician.

www.ebay.co.uk

Chris ??

 

[EuroTrotters]

That's on the outside of the fridge though, not the inside.

Doesn’t matter. You can get insulation breakdown both sides.

Any more photos ?

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[Richard n Ann]

The fins should be condensating and as the cabinet temperature drops they should start frosting (usually at one end)

From the photo it looks like the fins might not be getting cold make sure they are screwed tightly on and you could check the thermal paste behind while you're at it

 

[TinaLes]

Good advice thus far, I would unscrew the Ali finned plate, you will need to scrap off all the old paste which does get hard and becomes less effective over time, take your time doing this clean up all mating surfaces, and apply some new paste, you may need more than one tube as they are small.

To test the fridge door Gasket is sealing properly use the good old fashioned method of placing a piece of thin printer paper between the Gasket seal & the fridge frame, close the door, then pull out the paper slowly, if there is resistance then all is good, if not and paper pulls out easily, then you have a problem, check door hinge alignment, maybe try some rubber conditioner/cleaner, or get a new Door Seal Gasket from Thetford spares supplier.
Good Luck, you can buy the Paste on Amazon.

Long term you could think about fitting an internal thermostatically controlled fan, to circulate the air inside the fridge better, making the shelves top to bottom more equal in temperature. Examples of parts used and how to do this will be under the resources section, many have done this mod, especially for use in higher temps in summer above 25/27C.Very cheap mod, along with external fridge fans placed inside the top vent to increase cooling air flow at the rear of the fridge.
LES