Vent covers, why bother ? (1 Viewer)

ymfb

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Jun 16, 2017
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Could someone explain the benefits of fitting vent covers, also any reasons to not fit them.

Thanks
 
Jun 29, 2015
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caravan (for now)
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We don't use the MO HO in the winter apart from as a car, so don't fit the covers, the more air circulation the better. But if sleeping in it when it's cold we do fit them.

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Apr 27, 2008
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I fit the vent cover on the oven in the winter but don't bother with the fridge as it still seems to work fine. Unlike the fridge which is sealed the oven vent lets in a draught.
Perhaps in constant sub zero temperatures the fridge vent might help.
 

DuxDeluxe

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Jul 10, 2008
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My vent covers sit in the MH garage. Never used them but use the van all year round
 

Theonlysue

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Sep 14, 2009
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Not long enough!
Handy when its windy. Stops blowing the flame out.
I've camped in minus 15 and fridge worked better without covers than with.
Perhaps it's trial and error?
 

Shrimp

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May 27, 2015
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We put the covers on the other week when it was very cold and after a short time the fan was running, so we took them off again & it’s been fine.
 

Lenny HB

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Oct 18, 2007
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Use them all the time when the van is not in use, stops all the crap getting in behind the fridge. When the van is in use I fit them when it's cold but if running on gas I only fit the bottom vent.
I take them off when travelling as the have been known to come off and at over 40 quid a pair I don't want to loose them.

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Lenny HB

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Oct 18, 2007
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On the coast in West Sussex
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We don't use the MO HO in the winter apart from as a car, so don't fit the covers, the more air circulation the better. But if sleeping in it when it's cold we do fit them.
Sounds like you have a very dangerous fridge installation, the back of the fridge must be completely sealed from the habitation area for safety. If there are any draughts it needs sorting.
 
Jan 26, 2017
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Didn't know such a thing existed...

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TerryL

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This was covered in a thread a couple of weeks ago, but here is the real reason.

Your fridge has heating elements which are used to heat an evaporator, the cooling of which then cools the refrigerant liquid - sounds stupid but that's the physics of it, we all know evaporation results in cooling. Ordinarily the heating elements are able to provide enough warmth for the works to do it's job but if the outside temperature falls below a certain point insufficient heat is generated thus there is insufficient cooling. This in turn may* result in the temperature sensor inside the fridge demanding more cooling so the heating elements stay on longer - if you're on gas you may notice the gas burner running longer than usual. The point of the covers is to reduce the flow of outside air thus giving the heating elements a chance of doing a proper job and the manufacturers have specified a temperature at which point you should use covers. Incidentally you should never completely blank the vents off.

This also the reason you may be advised to turn the fridge controls down (i.e. less cooling) if you fridge doesn't appear to be working properly - again it sounds daft but it's true when you understand the physics.

*You note I say may. Some installations manage quite well without covers but it's also quite possible you never notice the fact that the heating elements are on longer than usual.

Tried to put it into basic language, but I only managed a "D" in O-level physics - at the third attempt!

As for reducing drafts, yes they're good at that too although that shouldn't be necessary in a properly installed fridge..........................

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Last edited:

Geo

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Jul 29, 2007
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pappajohn

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Aug 26, 2007
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The exhaust vent on my RV fridge was roof mounted, which most American RVs are, and on inspection the mesh insect guard had rotted through in places.
Removed the outer rain cover to replace the simple mesh guard and found an active bees nest.
It worth fitting the covers during none use/storage even in summer.
 
Feb 28, 2013
177
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Beware using the covers as recomended, up to plus 8C, I believe. I followed this instruction, the outside air temp was around plus 4C, and running on gas, anyway after getting a whiff of scorching, I found the top cover and slatted piece underneath warped. I can only assume it was due to heat build up. I now fit the top cover leaving a one slat space at the top. The covers are of the full width type and came with the van.

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TerryL

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Mar 5, 2010
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Beware using the covers as recomended, up to plus 8C, I believe. I followed this instruction, the outside air temp was around plus 4C, and running on gas, anyway after getting a whiff of scorching, I found the top cover and slatted piece underneath warped. I can only assume it was due to heat build up. I now fit the top cover leaving a one slat space at the top. The covers are of the full width type and came with the van.

It should never get hot enough to damage the vent cover - I think there might be a diffuser of some sort (there is on my Swift) but I'm no expert. Methinks a proper inspection might be called for. Anybody else ever suffered this fault?
 

Lenny HB

LIFE MEMBER
Oct 18, 2007
50,253
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On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
Beware using the covers as recomended, up to plus 8C, I believe. I followed this instruction, the outside air temp was around plus 4C, and running on gas, anyway after getting a whiff of scorching, I found the top cover and slatted piece underneath warped. I can only assume it was due to heat build up. I now fit the top cover leaving a one slat space at the top. The covers are of the full width type and came with the van.
On the big fridge/freezers the top vent gets very hot on gas, I just fit the bottom one when running on gas.
 

DBK

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Jan 9, 2013
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This was covered in a thread a couple of weeks ago, but here is the real reason.

Your fridge has heating elements which are used to heat an evaporator, the cooling of which then cools the refrigerant liquid - sounds stupid but that's the physics of it, we all know evaporation results in cooling. Ordinarily the heating elements are able to provide enough warmth for the works to do it's job but if the outside temperature falls below a certain point insufficient heat is generated thus there is insufficient cooling. This in turn may* result in the temperature sensor inside the fridge demanding more cooling so the heating elements stay on longer - if you're on gas you may notice the gas burner running longer than usual. The point of the covers is to reduce the flow of outside air thus giving the heating elements a chance of doing a proper job and the manufacturers have specified a temperature at which point you should use covers. Incidentally you should never completely blank the vents off.

This also the reason you may be advised to turn the fridge controls down (i.e. less cooling) if you fridge doesn't appear to be working properly - again it sounds daft but it's true when you understand the physics.

*You note I say may. Some installations manage quite well without covers but it's also quite possible you never notice the fact that the heating elements are on longer than usual.

Tried to put it into basic language, but I only managed a "D" in O-level physics - at the third attempt!

As for reducing drafts, yes they're good at that too although that shouldn't be necessary in a properly installed fridge..........................
This is quite a good description of how these type of 'fridges work. :)

https://www.arprv.com/how-dometic-norcold-fridge-works.php

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