Fridge vent covers

[a900ss]

I’m getting conflicting information and would really value real world experience from the group.

I’m off to the Alps on December and it will be cold.

I have a Dometic RMt7655L which will mainly be using gas (very little EHU), are fridge covers (top and bottom or just bottom) needed/recommended.

Many thanks.

 

[Nirvanauk]

Both are needed I'm anything below +5 in my book.

 

[poppycamper]

Can only say that I would be very wary using top cover with gas..
From personal experience the top vent area can get alarmily hot with cover on..
However except differant setups and fridges could have differant results....

 

[Palough]

Can only say that I would be very wary using top cover with gas..
From personal experience the top vent area can get alarmily hot with cover on..
However except differant setups and fridges could have differant results....

I can only comment from an Engineering perspective neither covers have any redeeming features.

Let's start with the top cover.

Firstly, burning LPG produces life threatening toxic gases, (Formeldahyde and Nitrogen Dioxide), and these toxic gases are intended to vent to the outside of the van, not be trapped inside!

Considering the fridge installation is not an airtight deal around the fridge body and the engineered escape route has been blocked by fitting a cover, it is highly likely these gases will enter the habitation quarters.

Both Formaldehyde and Nitrogen Dioxide are heavier than air but if they cannot vent freely to the ground they may enter the habitation quarters with unpleasant consequences.

In addition the flu gases are extremely hot.

Placing a hand over the vent pipe, see photo, for any length of time will blister the skin.

Any PVC covers are unlikely to appreciate this heat and may catch fire or at the minimum, scorch or melt

In addition, burning LPG produces water vapour which will also be trapped behind the cover and the condensation of the water vapour could have unintended consequences on electrical contacts and electronic components.

No, I certaywould not be covering the top vent louvres, not even in lay-up as they prevent the natural circulation of air for which they are designed and prevent the dehumidifying effect of natural air circulation.

Now for the bottom cover.

As mentioned, burning LPG produces water vapour which turns to condensation on cooling.

By covering the vent louvres, natural air circulation is prevented and water vapour is being concentrated.

Again, electronic components and electrical connections do not like being drenched in water, it's a substantial risk over time in my opinion.

Furthermore, the build up of condensation from ever increasing amounts of water vapour will most probably cause dampness in "out of view" wall paneling and timber studs and både plates with potential rotten wood work over time.

Finally, as mentioned in a previous post, the increased concentration of water vapour will inevitably cause accelerated corrosion of the gas burner jet assembly and block.

Refer to the attached photos of "normal" corrosion of the gas jet block assembly over a 2 year period.

Is possibly you could be cleaning the gas jet assembly every few months due to accelerated rust and corrosion deposits.

I certainly would not entertain the idea of covering the vent louvres even in lay-up conditions.

Apologies for the long winded Engineer's view point

 

[poppycamper]

and these toxic gases are intended to vent to the outside of the van, not be trapped inside!

Winter covers do not trap any gases in fridge housing...they are not gas tight... they have a 10 to 15mm gap to allow circulation.

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[headlight]

My upper fridge vent cover has the right hand side missing so the flue can vent to atmosphere.
No problems with heat or noxioux gases.
I put my vent covers on last week and they will be in place until spring.
I run my fridge on gas.

 

[Lenny HB]

Running on gas just fit the bottom cover, if you fit the top one it will get hot the plastic will go soft.

 

[headlight]

Running on gas just fit the bottom cover, if you fit the top one it will get hot the plastic will go soft.

I've checked my upper vent cover a few times to see if it was hot and it never has been.
Just warm and definitely not warm enough to affect the plastic.

 

[Lenny HB]

I've checked my upper vent cover a few times to see if it was hot and it never has been.
Just warm and definitely not warm enough to affect the plastic.

I've found they do on a 8505 160lt fridge freezer.

 

[headlight]

I've found they do on a 8505 160lt fridge freezer.

Bear in mind Lenny that my fridge/freezer is a small under work top, 18 years old 3 way absorption fridge.
It works fine but produces very little heat.
Probably why it also uses very little gas.

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[Lenny HB]

Bear in mind Lenny that my fridge/freezer is a small under work top, 18 years old 3 way absorption fridge.
It works fine but produces very little heat.
Probably why it also uses very little gas.

The bigger ones use a litre a day and the burner roars so a lot more heat being produced.

 

[headlight]

The bigger ones use a litre a day and the burner roars so a lot more heat being produced.

Yes Lenny exactly
If the 8505 are 160 litres I guess mine is half that capacity maybe less so maybe 70 litres ?
Also the freezer compartment is very small.
No idea really on its gas consumption but it is very little.
We have had about 50 nights away so far this year all bar 3 nights not on EHU so fridge, hot water, cooking and heating on gas (we haven't actually used the gas heating yet this year) and we started our 3rd 6kg Calor bottle last trip 3 weeks ago.
Obviously the next trips will use more gas as we will have the gas heating on.

 

[IRHP]

This is a copy of the Thetford 3000 series vent cover. It's not actually a cover but sits inside the vents. It does not seal but reduces the amount of cold air entering the bottom vent space. It's purpose is to make the fridge more efficient, nothing to do with keeping out rain or debris but it might help. Thetford advise fitting if temps are below 8c. If you don't fit one the fridge works just fine but will probably use more gas.
Now, when it gets below 3 or 4c why has no one invented a fridge that just brings in cold external air via some sort of thermostatically controlled vent?