# Mushroom Roof Vent do you have one?



## tattytony

I am looking for feedback from anyone that might have one of these mushroom vents fitted to their MH in the last five years, does your one leak or cause problems if so how what and why :? 

For those that have not read my ongoing problems this is an option offered to resolve a draft and rain ingress problem :x 

Many Thanks in Advance :wink:


----------



## spatz1

i think i have 2 in the sleeping area and 1 in the shower room....
mine are like a roughly 6 inch pipe with a pop up dome shaped cowel and have revearsable fans in and i ve always called them mushroom /pop up vents.....

hopefully from my description you can tell if they are somewhat like the one they propose to fit on your van, and if they are... they dont leak at upper motorway speed in heavy rain or stood...
can do a picture if you want...


----------



## tattytony

Anyone Please :?:


----------



## centrefire

*Dodgy cowel*

I have one fitted from new on my 2004 Rimor. Everything was ok until July of this year when I was parked up in Normandy during a Thunderstorm. Luckily enough it was daytime and a torrent of rainwater poured all over my cooker and worktop. Panic ensued and I had no choice only to brave the elements and climb onto the roof and investigate the source of the problem. I was parked level and i could see a pool of water lodged around the base of the extractor pipe on top of which was the cowl. I discovered that the cowel had worked itself upwards and allowed water to ingress. I Pushed it into place and that fixed the problem. There did'nt seem to be any adhesive or sealant holding on the cowel just a tight fit so i would advise each member with such a set up to check for a loose fit especially if your pride and joy is parked up for the winter. I was lucky that the camper was in use at the time or I would have a mobile swimming pool.


----------



## gerardjanice

We have a dometic cooker hood with a mushroom type vent/dome on the roof. 6 years no problems even with pressure washers.


----------



## tattytony

gerardjanice said:


> We have a dometic cooker hood with a mushroom type vent/dome on the roof. 6 years no problems even with pressure washers.


Its starting to sound ok but still could do with a few more points of view :wink:


----------



## tattytony

Surley there must be more than 2 people on MHF that have a mushroom vent, if not perhaps its a bad thing 8O


----------



## SNandJA

tattytony said:


> Surley there must be more than 2 people on MHF that have a mushroom vent, if not perhaps its a bad thing 8O


Is this what you mean?
Roof vent

Worth scrolling down to read reviews and some other similar products further down the page... it also misses a fly screen in the illustration which may be included I guess but would be worth checking for.

I have something similar venting the shower/toilet area. It doesn't seem to leak in the three years we have had the van. However I was cleaning the roof the other day and decided that sealant (where the inside vent assembly comes through the roof) seemed to be showing signs of age and have made resolution to reseal or probably replace the cowl assembly given the apparent low cost of the product shown. Currently looking for other possibilities at two local suppliers.

So to answer your question they probably do what they were designed to do but if you are near a marine supplier (we have a canal nearby with a chandler on the canalside) then you could look at the equivalent that they would supply perhaps? I'm guessing from the first post you made that you are installing one from scratch to solve some other issue, rather than a straight replacement?

Another link

Mushroom Vent listed as " caravan, motorhome & marine"

Steve


----------



## tattytony

Thanks Steve

Yes that looks like the one they are proposing to fit to the roof, I am just a bit worried about the potential that it might let in rain water when driving :?


----------



## SNandJA

tattytony said:


> Thanks Steve
> 
> Yes that looks like the one they are proposing to fit to the roof, I am just a bit worried about the potential that it might let in rain water when driving :?


Never had any indication of this happening with us. Only way perhaps this could happen with one fit for purpose would be if an airflow was created while travelling perhaps, in our case this would probably mean travelling with the "bathroom" window open, sucking a mixture of air and water from the airflow going along the roof. There must be thousands of these fitted to caravans and motorhomes and the topic of them leaking while travelling doesn't seem to turn up?

Given the shape of the mushroom cover and the construction where the inner ventilator sleeve comes through the roof and is capped by the outside dome then a depth of water would have to accumulate on the roof and "spill over" down the now extended central hole through the roof, or raindrops would have to bounce back of the roof and under the dome and then in the central "shaft". This would be a more of a problem if the mushroom cap was several inches above the roof and the rain was very heavy and probably the van stationary. Different forces present when you are driving along. 
So given the fact that they are installed with a low profile I guess this is why noone really is reporting having any trouble with them.

I'd stop worrying about it but consider it something to check in the future based on the couple of examples above and link below.

Pretty easy to replace
Replacing a vent

p.s. The benefits of extra permanent ventilation throughout the year would far outweigh any risk from water ingress.
Steve


----------



## SNandJA

Just read the original issue
Link to leaking Heki issue

Seems pretty clear that the original installation isn't satisfactory or "fit for use" as others have pointed out.

Given the apparent solution of some venting in the floor and in the roof inside a cupboard, I'd ask if they were sure you would get some kind of refreshment of the air in the van with the proposed solution and then get the Heki sealed as they suggest. If its a gas leak issue then the lpg collects at floor level and needs a means of escape, if combustion gas residue then a Carbon Monoxide detector would be a reassurance while the problem is fixed.

In transit then gas should be off either by manual means or the commercially automatic shut off devices available so a sealed Heki would be OK anyway. I guess it is left with partial seal to make sure that it is giving ventilation when you are parked up rather than rely on you opening the/a vent before using a gas appliance?

You have to feel it is a manufacturing (i.e. Autotrail's) fault - best of luck anyway. I think you can feel fairly certain that a mushroom vent wouldn't leak in transit.
If it is to be fitted in a cupboard then it is essential to make sure it has a fly screen to keep insects out - same thing for floor vent. All our van's orifices are fitted with mesh screens as it were :wink: !
Steve


----------



## tattytony

SNandJA said:


> Just read the original issue
> Link to leaking Heki issue
> 
> Seems pretty clear that the original installation isn't satisfactory or "fit for use" as others have pointed out.
> 
> Given the apparent solution of some venting in the floor and in the roof inside a cupboard, I'd ask if they were sure you would get some kind of refreshment of the air in the van with the proposed solution and then get the Heki sealed as they suggest. If its a gas leak issue then the lpg collects at floor level and needs a means of escape, if combustion gas residue then a Carbon Monoxide detector would be a reassurance while the problem is fixed.
> 
> In transit then gas should be off either by manual means or the commercially automatic shut off devices available so a sealed Heki would be OK anyway. I guess it is left with partial seal to make sure that it is giving ventilation when you are parked up rather than rely on you opening the/a vent before using a gas appliance?
> 
> You have to feel it is a manufacturing (i.e. Autotrail's) fault - best of luck anyway. I think you can feel fairly certain that a mushroom vent wouldn't leak in transit.
> If it is to be fitted in a cupboard then it is essential to make sure it has a fly screen to keep insects out - same thing for floor vent. All our van's orifices are fitted with mesh screens as it were :wink: !
> Steve


Again Thanks Steve

A very detail response with my mind now at rest also, I suppose my grudge was having another hole cut into the roof of new van just to compensate for bad design :roll:


----------



## Penquin

We have a mushroom vent fitted which only leaked when I broke the external cap - the whole vent is easy to replace and I did it in less than 1 hour.

BUT

I may be thick (no comments needed) but I cannot see how fitting one of these would solve the problem of water and air coming in and around the Heki.....

Are they planning on fitting the missing seal or a non-vented Heki?

If not why / how would fitting another vent help?

Dave


----------



## tattytony

Penquin said:


> We have a mushroom vent fitted which only leaked when I broke the external cap - the whole vent is easy to replace and I did it in less than 1 hour.
> 
> BUT
> 
> I may be thick (no comments needed) but I cannot see how fitting one of these would solve the problem of water and air coming in and around the Heki.....
> 
> Are they planning on fitting the missing seal or a non-vented Heki?
> 
> If not why / how would fitting another vent help?
> 
> Dave


They (being Autotrail) have fitted a vented heki which is sealed on the leading edge and 2inches of 2 sides but not around the other 2/3rds of the heki so when driving I get some form of turbulance and causing a draft to come in the heki and if raining that too :x , they (being Chelston where I bought it) are saying fit the vent and seal all round the heki no draft or rain (I Hope) 8O


----------



## SNandJA

tattytony said:


> Penquin said:
> 
> 
> 
> We have a mushroom vent fitted which only leaked when I broke the external cap - the whole vent is easy to replace and I did it in less than 1 hour.
> 
> BUT
> 
> I may be thick (no comments needed) but I cannot see how fitting one of these would solve the problem of water and air coming in and around the Heki.....
> 
> Are they planning on fitting the missing seal or a non-vented Heki?
> 
> If not why / how would fitting another vent help?
> 
> Dave
> 
> 
> 
> They (being Autotrail) have fitted a vented heki which is sealed on the leading edge and 2inches of 2 sides but not around the other 2/3rds of the heki so when driving I get some form of turbulance and causing a draft to come in the heki and if raining that too :x , they (being Chelston where I bought it) are saying fit the vent and seal all round the heki no draft or rain (I Hope) 8O
Click to expand...

I don't know what conversations you've had with Autotrail and the Dealer but the reason for ventilation is indicated on this link

HSE Report on Standards for Caravans etc.

A house has natural ventilation to cope with gas fires up to 3kw without an airbrick I think. So without giving you sleepless nights, you'd hope that Autotrail would be aware of the BSI standards for motorhome ventilation and that a mushroom ventilator would probably give more than the omitted seal "system" on the Heki.

As others mentioned elsewhere we have a large vent to outside in the stairwell, the bathroom is covered for damp/condensation issues by the mushroom in the roof, our lpg locker has a grill to let gas escape through the bottom of the locker and this is also shared by the void under our cooker. Similar grill under our gas/electric fridge. We have gas space and water heating which draws air in via a vent in the side of our fixed bed and the products of combustion go out through the side of the van to outside. Over the gas hob is a Fiamma opening roof light which has permanent ventilation even when fully closed for travel and for cooking when outside conditions dictate.

I'd guess if you look around your van, perhaps in conjunction with your dealer you could identify similar ventilation places. So the issue the Heki ventilation seal removal is probably addressing, is avoiding the build up of the products of combustion especially Carbon Monoxide (CO) the silent/odourless killer! CO is slightly lighter than air but is unfortunately a good mixer and has a tendancy to stay at the level it is produced. General advice for the everyday safety check of a gas appliance is that if a gas appliance burns with a yellow flame then it needs checking as it should burn mainly blue. You may remember the Bunsen burner from schooldays? airhole closed - yellow flame, airhole open more oxygen gives blue flame and efficient burning....

So you could apply test this "blue flame" production using the gas hob whilst at the Dealer after they seal the Heki and before the vent is installed.

For peace of mind with any gas appliance then a Carbon Monoxide dectector is worth the expense.

Hopefully an expert will add to the post and correct any errors but I think I'd have faith in the dealer and Autotrail's solution especially if you are satisfied that the mushroom vent is going to get the van to meet the ventilation standards from the BSI. From the above HSE document it is BSI EN 721 that needs to be met? You can search for a summary of what it deals with but it would cost £74 to wave it under Autotrail's nose as you stamp!!

Steve


----------

