Fridge freezer performance in hot summer ambient conditions

[68c]

One problem with three way fridges is they are not good at staying cool if not on gas or electric. ie if you forget to switch to gas when parked up after driving. The heat exchanger that draws the heat from the fridge to the cooling coils will work in either direction, hot sun on the fridge grills and the fridge will very slowly heat up. This is not such a great problem with compressor fridges.

 

[MartinandBev]

I had it running on Gas for 24 hours outside my house, iv just switched to EHU to just see if this makes a difference, but I think I’m clutching at straws

 

[Richard n Ann]

Well just as an update, stripped mine back and removed the evaporator fins, and cleaned the pipe and applied loads of new thermal paste, but alas freezer performance is good. -25, but the fridge will only just scrape 10 degrees and that’s with a fan on the bottom drawing in air and a fan at the top exhausting air - my only conclusion now is the fridge is knackered (it’s only 4 years old) and time for a new one - ouch

Where is the minus 25° being measured from? Is it the air temperature in the freezer compartment or the fin temperature? I'm thinking the system might be short of gas with most being boiled off before it reaches the fridge.

Also where exactly are you measuring the fridge temperature and how full is it? Are the fridge fins frosting or just condensation?

 

[MartinandBev]

Where is the minus 25° being measured from?

i am using a digital laser thermometer and taking the temps in the middle between top shelf and roof, and middle of bottom compartment - no fins in the freezer

for the fridge I’m taking a temp at top, middle and bottom of the frodge

the fins are not freezing at all, in fact don’t feel that cold, like I said around 10-12 degrees

when I turned it upside down last week it didn’t sound like there was a lot of liquid in it, but there again I didn’t know what to expect, so this might be right

iv been told that the systems are not refillable? Is that right ?

 

[Richard n Ann]

N

no fins in the freezer

What removes the heat from the freezer then? Looked at an exploded diagram of your fridge/freezer and can't see anything in there

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[MartinandBev]

N

What removes the heat from the freezer then? Looked at an exploded diagram of your fridge/freezer and can't see anything in there

Pass on that one, not sure but yes the freezer is empty

 

[Richard n Ann]

the systems are not refillable? Is that right ?

Correct

 

[MartinandBev]

Correct

guessed so, I’m going to get it pressure tested tomorrow, amd if that confirms there is a leak then it’s definitely new fridge time, but it won’t be a Thetford, I’m thinking the new Dometic 10 series which appears on paper to have superior cooling performance and is a direct swap out according to this file

 

[Richard n Ann]

guessed so, I’m going to get it pressure tested tomorrow, amd if that confirms there is a leak then it’s definitely new fridge time, but it won’t be a Thetford, I’m thinking the new Dometic 10 series which appears on paper to have superior cooling performance and is a direct swap out according to this file

Don't know how they'd go about pressure testing. There's no standard gauge connection point and if they put nitrogen in to pressure test they've ruined the refrigerant charge, which should be a precise amount of water and ammonia.

There may well not be anything wrong with it from what you've said, it all depends on what exactly you've been measuring with the laser thermometer. Also the fridge will take many hours to frost the fins if it's been loaded up with room temperature food & drink etc or if there's a gap in the seal the fins will never frost up.
How does it perform in real life? Are the beers cold?

 

[busbuddy]

Don't most of the fridge specs say they will cool to something like 25 degrees below ambient so if it's in the 30s you are struggling, fitted fans in my old karmann but the swift seems to cope better

An update to this post
Because of 2019 hot weather/lockdown I decided to try the re-pasting of the cooling element and due to a recommendation on here I bought a cbe fan kit.....it is now 2021 and scorching (for the uk).....I can quite easily freeze strawberries, coke, cucumbers and pretty much any salad if I turn the fridge up

Not sure which made the most difference, paste or fans but my fridge is the 6270 dometic and 2003 vintage working fine

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[MartinandBev]

Don't know how they'd go about pressure testing.

I am not sure either, but will leave it at the dealers for the day.

as for your second point about the beers being cold, colder than a shop shelf, but not cold if that makes sense. We are also losing food through it going off, and the butter is soft, which isn’t ideal, so I am confident it’s not working as it should, Thetford replied to me eventually and state that in an ambient temperature of 30 degrees, I should with a ventilation kit get a temperature of circa 5-7 degrees in the fridge.

as for measuring the temp, I am pointing the laser thermometer at the back panel and holding it at the front of the shelf, so a distance of circa 12-14 inches, basically the depth of the fridge

 

[Graham of Madrid]

Maybe the dealer has a digital laser pressure tester or maybe ....... not. There's no schrader valve is there - then again how it is filled at the factory ?

 

[Richard n Ann]

Maybe the dealer has a digital laser pressure tester or maybe ....... not. There's no schrader valve is there - then again how it is filled at the factory ?

Probably same as domestic fridges, after charging the stub is welded up. (saves them 10p on a ¼ schrader )

 

[MartinandBev]

OK - so the system has hardly any fluid in it, couldnt be pressure tested as nowehere to connect to , but they removed it and tipped it upside down and hardly any fluid could be heard moving from bottom to top / and vice versa, they then connected it up on the bench and whilst the freezer is freezing, which it should do first there is nothing to help the fridge cool, all that is happening is res idual cooling from freezer

So 1400 euros later and a new fridge being delivered tomorrow, they wanted 500 euros for fitting, i think not !!, I can do this, the hardest bit is going to be getting old one out and new one in, but am thinking remove the passenger seat and go in through the door

 

[Bucket]

Reading this thread took me back to our fridge saga along very similar lines some yeas ago.
After various expensive changes I also junked the Thetford for a dometic RMD 8505.
While better, it still really struggled in hot conditions. Then one day I noticed that the fitting instructions specified larger vents. I had just assumed the factory fitted ones would be OK for a same size fridge. I installed the larger vents and it was much improved, meaning the original manufacturer (Chausson) had used the wrong ones to start.
I also added pc fans like others for the extra help when really hot.
So it's likely the old Thetford was simply not getting enough ventilation, by then it was long gone so too late.

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[Jim and Louise]

Draw cool air in through the bottom vent which then passes up taking heat away from the cooling fins on the condenser pipework near the top of the fridge and out through the top vent.

The fans on the top vent are drawing hot air out.

Many thanks

 

[RM_Marine]

Ive just ordered this

OTOPARTS | bedrijfswagen en camper accessoires

OTOPARTS | accessoires voor camper en bedrijfswagens

www.otoparts.nl

After finding it on this site here

Fitting CBE fridge fans

When this was discussed recently there seemed to be some interest in a thread on fitting this kit so here goes. I bought the CBE kit from the Netherlands for Euro 54.50 inc delivery, it was a lot more from UK sites and the Dometic kit is around £80. So in the kit you get two fans in a frame...

www.motorhomefun.co.uk

And these to wire it

Halfords Cable Connector Self Strip Red (HEF604) | Halfords UK

Shop the latest Halfords Cable Connector Self Strip Red (HEF604) joins two cables together at Halfords UK

www.halfords.com

I've also got a I line fuse but not sure I need it???

 

[gus-lopez]

then again how it is filled at the factory ?

Yes as Richard n Ann said filled, crimped & end welded.

 

[Chrisvh]

Ive just ordered this

OTOPARTS | bedrijfswagen en camper accessoires

OTOPARTS | accessoires voor camper en bedrijfswagens

www.otoparts.nl

After finding it on this site here

Fitting CBE fridge fans

When this was discussed recently there seemed to be some interest in a thread on fitting this kit so here goes. I bought the CBE kit from the Netherlands for Euro 54.50 inc delivery, it was a lot more from UK sites and the Dometic kit is around £80. So in the kit you get two fans in a frame...

www.motorhomefun.co.uk

And these to wire it

Halfords Cable Connector Self Strip Red (HEF604) | Halfords UK

Shop the latest Halfords Cable Connector Self Strip Red (HEF604) joins two cables together at Halfords UK

www.halfords.com

I've also got a I line fuse but not sure I need it???

I have a feeling Otoparts will cancel the order as they no longer deliver to the UK. Hope I am wrong. If so an Italian dealer on EBay will deliver for the same money.

 

[RM_Marine]

Have you got a link to the Italian seller please

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[Chrisvh]

Search Simat Shop on Ebay or cut and paste this into the EBay search window. Currently have one left.
Kit Vents For Fridge Camper CBE MCV-2 MCV 2 With Controler Remote Brown

I ordered from Otoparts at the weekend and they cancelled the order. I have now ordered from this EBay seller. Best of luck.

 

[TerryL]

Search Simat Shop on Ebay or cut and paste this into the EBay search window. Currently have one left.
Kit Vents For Fridge Camper CBE MCV-2 MCV 2 With Controler Remote Brown

I ordered from Otoparts at the weekend and they cancelled the order. I have now ordered from this EBay seller. Best of luck.

That's the one I ordered - took about 10 days to be delivered.

After a very hot Stratford my observations are that it didn't make much difference to the time the gas was running but the fans were running almost constantly, often on the high setting. The fridge performed okay anyway, bearing in mind the very high ambient temperatures, even turned down to 2 bars. Jury is still out on the question of was it a waste of money!

 

[SteveRallye]

Our Dometic packed up on electric in last years heatwave (on a hot sunny hillside fridge side) but came on next morning on gas. since we got it fixed I mainly run it on gas on No.2 setting and so far this year it has run well during our latest 30deg heatwaves though keep meaning to get a couple of fans fitted. We try to keep it in shade luckily its Hab doorside.

 

[gus-lopez]

**I used to install fly screen on both upper & lower fridge vents to prevent the flies getting inside .I have to remove it in springtime to allow unrestricted air flow.
You would not believe how much air flow is restricted by a net full of holes**

Removing this has made a tremendous difference. Fridge stays around 2,9º with ambient of 36/37º & remains the same when directly in the sun which I tried today as it is usually parked with fridge in the shade

 

[MartinandBev]

Well my new fridge arrived, took off the evaporator plate and splodged loads more thermal paste over it, removed Mosquito netting, and left overnight, freezer -24, fridge 3 degrees, ambient temp, 33 degrees, so I’m well pleased, yes cost 1400 euros, but at least I have a working fridge and thus cold beers

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[Bustup15]

Following the temperatures at Stratford meet I'm putting a fan system into the van.

Controller

Aideepen STC-1000 DC 12V 10A Digital Thermostat Temperature Controller Thermostat Control Switch 2 Relay Output and NTC 10K Thermistor Sensors Digital Temperature Probe​

2 Fans

Noctua NF-P14r redux-1500 PWM, High Performance Cooling Fan, 4-Pin, 1500 RPM (140mm Grey)​

Fans mounted inside the top vent directly above the cooling fins and the controller mounted in the mesh grill above the tower fridge/oven.

All wiring done today and the metal grill cut out and resprayed. Ready for fitting and testing on Tuesday.

Will measure the before and after results over the trip to Isle of Wight next week where we will hopefully have warm weather and cold beer .

What start/stop temperature settings have been found to be most effective by others?

 

[Richard n Ann]

What start/stop temperature settings have been found to be most effective by others?

That depends where the sensor is. Mine is in the fins on the left hand side (coolest side) and the controller switches the fan on at about 42°c

 

[Two on Tour]

My sensor is also in the condenser fins just at the hot to cooler transition point and set at 40.5c

 

[Bustup15]

Yes, my sensor is similarly positioned. Thanks for the temp info

 

[Two on Tour]

On my controller I have the TS (temperature set value) set to 38c and the DS (difference set value) set to 2.5c.
The figures are very likely to end up different with fridge when you tune it in, but between mine and Richard's it will give you a good starting point.

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