Domestic mains Fridges

[SquirrellCook]

A little something worth mentioning is the climate grade when choosing a domestic fridge for motor home use.
Many people don’t know about this, but many fridges are designed to be used inside a house. Generally these have reasonably stable temperatures.
For motor home use, you should be looking for a class SN T. This is the widest temperature operating range.

 

[wildebus]

A little something worth mentioning is the climate grade when choosing a domestic fridge for motor home use.
Many people don’t know about this, but many fridges are designed to be used inside a house. Generally these have reasonably stable temperatures.
For motor home use, you should be looking for a class SN T. This is the widest temperature operating range.

You would be hard pushed to find a T rated fridge in the UK I would think?
I would think the ST rating would be fine for most motorhomers? (how many times are you above 38C inside the van?)

 

[SquirrellCook]

They are about If you look. I think they are aimed at garage/conservatory use.

 

[wildebus]

Out of curiosity I had a look at the class of the [12V] Fridge I was contemplating buying (at the right price):

Climate Class: Day mode: SN-T(10°C-43°C) Night mode: SN(10 °C -32°C)
"night mode" was a slightly more economical and quieter operational mode.
So a very wide range there which is good (but at a price!)

Two things come to mind:
1) A Fridge running to a "T" spec would (based on the above) would be both noisier and use more power?
2) "Night Mode" would probably be suitable for the majority of the year in the UK, day or night?

Does a fridge with a different/wider climate class have a different compressor? Are they usually switchable to different ranges?

In my own case, the fridge I fitted is a N-ST (16C - 38C) which, TBH, I think is fine as I don't expect to be anywhere at the higher temp. And with the forced air from the fans which speed up as the temp increases, will I think control and keep higher temps down well.
The lower temp number of 16C is quite high but as the fridge is in an enclosed area it will warm itself up anyway (the typical garage fridge is generally in the open and will be whatever the general ambient room temp is).
Maybe in the winter it would be worth blocking the external vents to keep the working area warmer? put in winter covers like for the 3-ways (or get a piece of cardboard a lá car radiator blocking in winter )

 

[SquirrellCook]

I've not been able to find any sensible information on the construction of the fridges. My guess for the higher range it would have better insulation and radiator. I did wonder why you decided to blow, rather than suck? I used fridge vents with covers not only for that reason, but as my installation is not that well sealed it can get draughty inside.
The fridges I've used are very cheap, unlikely to have different power settings.
The refrigerators that use the Danfoss BD35F pump can be very adjustable.

 

[mistericeman]

Invertor compressor (NOT invertor powered) fridges are becoming more common these days (and coming down in price too)

Won't be long till all fridges will be the same as the aircon units we fit and maintain/repair have done over the last few years.

Vastly more efficient than none invertor and quieter with lower start up currents...
As well as being far far better at temperature control.

 

[wildebus]

I've not been able to find any sensible information on the construction of the fridges. My guess for the higher range it would have better insulation and radiator. I did wonder why you decided to blow, rather than suck? I used fridge vents with covers not only for that reason, but as my installation is not that well sealed it can get draughty inside.
The fridges I've used are very cheap, unlikely to have different power settings.
The refrigerators that use the Danfoss BD35F pump can be very adjustable.

Quite simple really.
I could directly the airflow specifically to the area I wanted. If I went for the sucking option, the fans would be at the top and it would be pulling air from the general rear area and potentially not really affect the temperature around the compressor housing area very much
That option just didn't seem very efficient? I can if I want move the fans to the top to suck up (unlikely to do so) or add another couple of fans to operate in tandem with the lower pair (more likely but still not actually that likely unless plan to travel to southern Europe)

FWIW, the Titan Fan kit I installed in auto mode has a preset "on" temperature of 20C, at which time it starts and then increases as the temp increases. I read quite a few comments about that 20C being too high and how 15C would be better. I don't know what it is, but I think there is likely an optimum operating temp and it is certainly not neccessarily as low as possible as many people seem to think (hence why Garage Fridges can often work poorly).

 

[SquirrellCook]

The funny thing is that when the garage is cold, the weather is doing the job of the fridge! We have an outside freezer too, no problems as yet.
We have not had any trouble cooling Murky's in all conditions encountered so far.

 

[mistericeman]

Frankly a standard compressor fridge should easily cope with most situations unless your visiting the Sahara or the Arctic as compression refrigeration is far more tolerant of temp ranges....
Aided by what you are actually cooling is a small and usually enclosed area not subject to high heat loadings.....

Unlike absorbtion cooling which is far more fickle due to the chemical changes involved....

Compression Aircon units are tolerant too though they DO use forced airflow on the condensing units to deal with the high heat loads they need to deal with (large warm room rather than a small box)
So utilise head pressure controlled fans to maintain efficiency and prevent over condensing at lower ambient temps (server rooms etc in winter time)

Next important step in fridges will definitely be Inverter compressor units to improve energy efficency and better temperature control...

 

[RV2MAX]

I used a Beko two door in my RV to replace the US 3 way , it was rated for garage use (ie unheated ambient) IIRC this is to deal with posssible thermostat problems as it was sealed in cabinet with external vents . It worked well without any problem in below freezing and 38C+

 

[ScoTTyBEEE]

In my own case, the fridge I fitted is a N-ST (16C - 38C) which, TBH, I think is fine as I don't expect to be anywhere at the higher temp. And with the forced air from the fans which speed up as the temp increases, will I think control and keep higher temps down well.
The lower temp number of 16C is quite high but as the fridge is in an enclosed area it will warm itself up anyway (the typical garage fridge is generally in the open and will be whatever the general ambient room temp is).
Maybe in the winter it would be worth blocking the external vents to keep the working area warmer? put in winter covers like for the 3-ways (or get a piece of cardboard a lá car radiator blocking in winter )

The inventor fridge I have (on your recommendation) is a N-ST. It's been running solid for 10 months in Portugal, at times my van has been up to 38 degrees when all the doors are shut and I'm elsewhere.
Works perfect, however, I needed to put a temperature controlled fan (120mm) blowing on the compressor otherwise it seemed to get into a runaway situation where the compressor causes the heat and the sides of the fridge get super hot. Now zero problems, I think I set the fan to come on at 40 and off at 35, something like that.
It's also got 15mm ply covering both sides but this doesn't seem to have a negative effect with the fan addition.
Also had no problems down to around 7 degrees.

 

[wildebus]

The inventor fridge I have (on your recommendation) is a N-ST. It's been running solid for 10 months in Portugal, at times my van has been up to 38 degrees when all the doors are shut and I'm elsewhere.
Works perfect, however, I needed to put a temperature controlled fan (120mm) blowing on the compressor otherwise it seemed to get into a runaway situation where the compressor causes the heat and the sides of the fridge get super hot. Now zero problems, I think I set the fan to come on at 40 and off at 35, something like that.
It's also got 15mm ply covering both sides but this doesn't seem to have a negative effect with the fan addition.
Also had no problems down to around 7 degrees.

That is useful to know.
For a few days a couple of years ago, the rear of my fridge hit around 44C due to a bit of a heatwave and the fan didn't manage any cooling as the whole van was at that but the airflow probably helped
Here in Scotland, the lower temperatures are the ones more experienced! my Inventor would have been in a Freezing temp quite often and didn't seem to have any untoward effect on it.

 

[mistericeman]

That is useful to know.
For a few days a couple of years ago, the rear of my fridge hit around 44C due to a bit of a heatwave and the fan didn't manage any cooling as the whole van was at that but the airflow probably helped
Here in Scotland, the lower temperatures are the ones more experienced! my Inventor would have been in a Freezing temp quite often and didn't seem to have any untoward effect on it.

Lower than design temps with a fridge just make it more likely to run colder as the condenser coil becomes super efficient at shedding heat....
And leading to over condensing (probably start to get the inside running colder than set on the stat and possibly freezing in the fridge section)
Not usually a massive issue as it leads to the stat calling for cooling less often....
IF it was an aircon unit the indoor unit /evaporator would start to freeze and start off a loop where air flow over the evap is obscured by ice and a spiral towards turning into a block of ice

 

[Millie Master]

I have a WAECO CR50 12v fridge fitted to 'Millie' and it is the only thing I would contemplate changing with the build because of the length of time the compressor runs at times.
For ventilation, I installed a 4" diameter drainage pipe through the floor (which I suitably covered in a metal mesh to stop rodents gaining entry) and directly above the fridge/cupboard unit there is a 4" di. mushroom vent in the roof.

I removed the fridge only yesterday to thoroughly clean all the compressor cooling pipework after 6 years of use only to find that there wasn't all that much dirt and not a single cobweb, so I am now thinking about finding a company who can recharge the system as well as introducing a small diameter fan into the bottom pipe so as to increase the throughput of air from under the van. But even yesterday, it was quite noticeable how much cooler the air was entering the inside of the van above this inlet pipe.

 

[trevskoda]

My we el cheepo fridge has the back all inclosed and no comp to see, hit 38c when I was looking and maybe a tad higher, never gave a problem and cooled to 2c night and day.

 

[wildebus]

I was at building centre counter today and they had one of those mini-fridge on the counter with the glass door for sale.

Fittingly they also had box of Earplugs on top ... it was very noisy
Just mentioning this to say that the noise aspect is a very important factor as well and many standard fridges are not that quiet as it is expected they will be in the kitchen or utility room.
(oddly enough it is the cheaper smaller ones that seem to be best as they are often used in smaller properties where the kitchen might be open plan or in bedsits).