Stuart Posted January 18, 2010 Share Posted January 18, 2010 My roof lights have finned vent slots all the way round. I cannot see the need for these, especially in winter when the hot air just goes straight out throught the lid. I have taped them all with masking tape, easy to pull off if summer comes. What does anybody else do? Stuart Link to comment Share on other sites More sharing options...
Guest Tracker Posted January 18, 2010 Share Posted January 18, 2010 I stuff foam plastic in the vents around the big Heki skylight as well as extending the draught excluder around it to seal all four sides. In the old days pre bloody great skylights I had carpet covered plywood squares which were a tight push fit into all of the roof light apertures and these made a huge difference to heat retention. Some of the PC brigade will condemn me for this with talk of condensation and ventilation issues but I prefer to be nice and warm and snug! Link to comment Share on other sites More sharing options...
colin Posted January 18, 2010 Share Posted January 18, 2010 On my van fixed ventilation is left clear to prevent condensation, I built/designed it to do so and it works. I've seen to many houses and statics that have been damaged by blocking up vents "to stop the draughts" Link to comment Share on other sites More sharing options...
CAB Posted January 18, 2010 Share Posted January 18, 2010 I am probably wrong as I freely admit to not understaing the operation of gas appliances - but will raise the issue anyway as it is potentially fatal and accept being shot down. Do some of the earlier gas space heaters not have dedicated ventilation and require a free flow of air? Risk of carbon monoxide poisoning? Certainly in my home the CORGI engineer (or whatever it is now GasSafe?) insisted I fitted a larger air brick in the utility room with my gas central heating for safety - but that's going back a few years. Probably not an issue with modern units, but I for one would rather be safe than sorry - if only when cooking on gas. Clive Edit - put the word "engineer" after CORGI as I am sure some bright spark would have dogged me with this pun. Link to comment Share on other sites More sharing options...
Guest Tracker Posted January 18, 2010 Share Posted January 18, 2010 Ever since I've had a van with properly installed heating as opposed to very early ones with an unsatisfactory and often user fitted internal radiant gas fire they have always been both air intake and exhaust flued externally. The fridge should in theory be sealed to the internal living space - but very rarely is - another good place to do some draught excluding! The oven and hob will of course emit fumes and CO into the van but as they are usually only on for a limited time and often with an slightly open window or extractor fan whilst cooking I don't see CO fumes as a real problem. NEVER use the cooker for space heating as that IS dangerous. Link to comment Share on other sites More sharing options...
Mel B Posted January 18, 2010 Share Posted January 18, 2010 I've cut down an old foam camping bed roll in to strips as it was just the right thickness to go in the edges of the acrylic vent top all the way round, it is double skinned with air vents in between, so that's stopped it - I had done it previously but they 'escaped' so this time I've secured them with some quality gaffer (duct) tape, much warmer now and I don't get a draught in bed any more, used to be blooming freezing. There are enough other smaller draughts in a motorhome so being snuffed out isn't a major concern! Link to comment Share on other sites More sharing options...
Basil Posted January 20, 2010 Share Posted January 20, 2010 Tracker - 2010-01-18 8:11 PM The oven and hob will of course emit fumes and CO into the van but as they are usually only on for a limited time and often with an slightly open window or extractor fan whilst cooking I don't see CO fumes as a real problem. NEVER use the cooker for space heating as that IS dangerous. Sorry Tracker but this statement is completely inaccurate, no gas appliance that is combusting correctly will give off CO (Carbon Monoxide), they do not emmit 'fumes' either, the correct terminology being products of combustion. This is not being pedantic it is a very important distinction as 'fumes' may be dangerous the 'products of combustion' from a correctly burning appliance are totally harmless and are CO2 (Carbon Dioxide) and H2O (Water Vapour) exactly the same as you and I breath out. There is also Nitrogen in the 'products' but this is simply what is left over from air when the Oxygen required to support complete combustion is used up in the process, this is also a harmless product and what around 80% of the air around you is made up from. If you have an appliance that is giving off CO, a lethal and odurless gas then it needs inspecting and correcting by someone who knows what they are doing. Using a cooker for space heating or a flueless appliance, though not to be recommended, is not dangerous at all PROVIDING the permenant ventilation has not been blocked up. However the massive amounts of H2O (Water Vapour) that will be produced is not very condusive to the atmosphere within the living space. Bas Link to comment Share on other sites More sharing options...
Brambles Posted January 20, 2010 Share Posted January 20, 2010 ...and then next you guys all will be asking how do I cure condensation!!! *-) Link to comment Share on other sites More sharing options...
Guest Tracker Posted January 20, 2010 Share Posted January 20, 2010 Thank you Bas - I sit corrected! Condensation Jon? What condensation - not a problem! Link to comment Share on other sites More sharing options...
colin Posted January 20, 2010 Share Posted January 20, 2010 Basil - 2010-01-20 12:05 PM This is not being pedantic it is a very important distinction as 'fumes' may be dangerous the 'products of combustion' from a correctly burning appliance are totally harmless and are CO2 (Carbon Dioxide) and H2O (Water Vapour) exactly the same as you and I breath out. Using a cooker for space heating or a flueless appliance, though not to be recommended, is not dangerous at all PROVIDING the permenant ventilation has not been blocked up. However the massive amounts of H2O (Water Vapour) that will be produced is not very condusive to the atmosphere within the living space. Bas Well you've partly corrected yourself, co2 is normaly nowhere near as dangerous as co, but it will still kill you in high enough concentraitions from memory around 10% I believe. Link to comment Share on other sites More sharing options...
colin Posted January 20, 2010 Share Posted January 20, 2010 Brambles - 2010-01-20 12:35 PM ...and then next you guys all will be asking how do I cure condensation!!! *-) It now dawns on me why people bang on about using external silver screens to prevent condensation *-) Link to comment Share on other sites More sharing options...
CAB Posted January 20, 2010 Share Posted January 20, 2010 Carbon dioxide is not toxic in the conventional sense, but in moderate concentrations (1-5%) will cause a noticeable increase in breathing and heart rates. At around 5% concentration you will begin to smell it (it's like getting fizzy pop up your nose as a youngster - more of a tingle). At higher concentrations it can cause suffocation. But to get back to the original post.. Carbon monoxide is extremely toxic - it will attach itself very strongly to the haemoglobin in red blood cells and so prevent the transport of oxygen around the body. The amount of CO produced by combustion of carbon-based fuels (diesel, petrol, methane - natural gas, butane, propane are all hydrocarbons) in a well-ventilated space (plenty of oxygen) is minimal and will cause no adverse side effects. The reason that turning on the gas burners on a stove (or any naked flame) in a poorly ventilated space is dangerous is that as the compbustion proceeds the level of oxygen diminishes and as a consequence the proportion of carbon dioxide in the combustion products decreases, and that of carbon monoxide increases. Carbon monoxide has no smell and initially causes headaches and drowsiness. You may go to sleep and not wake up. It's deadly. This is the reason I would never reduce the ventilation in a motorhome - even though for safety's sake manufacturers will ensure there is far more than needed. How would you know how much ventilation can be safely blocked off? I am sure that others will disagree, but it's a personal choice. Clive Link to comment Share on other sites More sharing options...
Brambles Posted January 20, 2010 Share Posted January 20, 2010 I will go along with what you have said CAB, Excellent post. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 21, 2010 Share Posted January 21, 2010 I believe there are guidelines - or perhaps even regulations - defining the amount of permanent ventilation a leisure-vehicle should have, and I vaguely recall seeing some figures, based (if I remember correctly) on the size of the vehicle's living area, in an older CAK brochure. Presumably such 'rules' go back to when open-flame heaters were used in leisure vehicles and may well link to domestic building regulations. I did come across this when I was looking for information: http://www.warwickshire.gov.uk/Web/corporate/pages.nsf/Links/B87CFD4F8A770CA480256E510055FD41 I don't mess about with my motorhome's roof-light ventilation either, though it perhaps needs saying that the Hobby doesn't have any of the haphazardly positioned 'gas drop' holes in the floors that UK-manufacturers insist on and that must contribute to cold-weather draughtiness. Link to comment Share on other sites More sharing options...
CAB Posted January 21, 2010 Share Posted January 21, 2010 In gas lockers (particularly those with internal access) the holes in the base of the locker are essential. Butane is almost exactly twice the density of air, and propane about 1.5 times. In the event of a leak both will therefore collect at the bottom of the locker and flow downhill like a fluid into whatever areas they can find. This is almost certainly the reason ventilation is provided at a low point in the living area. Apart from the obvious dangers of an explosion there have been cases of people being suffocated by the butane (one springs to mind a little while ago of a narrowboat where sleeping occupants were suffocated by a butane leak - not easy to provide low-level ventilation in this situation). I experienced a leak fairly recently where I lost all of the gas in my bottle - but fortunately it was an external fixed refillable tank. It shouldn't have, but it can and does happen. Domestic and bottled gases have no discernable natural smell. This is added by suppliers to give them their characteristic odour - and is also the reason why they all have the same smell. To come clean on my situation I first smelled the gas whilst parked in a street - but there was a hole being dug by a gas company a short distance away so I but two and two together ... It was only when I was back home on our sloping driveway I realised I was the source - the escaping butane rolled down our drive into the garage. And yes I should have turned the main cylinder valve off when not in use - but it's in an awkward position under the van. Lesson learned. Clive Link to comment Share on other sites More sharing options...
Mel B Posted January 21, 2010 Share Posted January 21, 2010 CAB - 2010-01-20 11:32 PM This is the reason I would never reduce the ventilation in a motorhome - even though for safety's sake manufacturers will ensure there is far more than needed. How would you know how much ventilation can be safely blocked off? I am sure that others will disagree, but it's a personal choice. Clive In our motorhome we have a large 'drop out vent' in the footwell next to the habitation door, there are other vent areas too, so blocking off the roof vent above the bed which just lets lots of cold air in and a breeze at the best of times is very beneficial. Without it being blocked, it's like sleeping in draughty room with a cold breeze blowing on your head all night and therefore you don't get much sleep. I hasten to add that the Heki roof vent is not blocked off either. Anyone thinking of blocking off ANY vents/areas must check that there are sufficient areas left unblocked to be safe. Link to comment Share on other sites More sharing options...
Brambles Posted January 21, 2010 Share Posted January 21, 2010 "Anyone thinking of blocking off ANY vents/areas must check that there are sufficient areas left unblocked to be safe." How does one go about determining what is regarded as 'safe' without knowing what the recommended ventilation area is required for a given volume of Motorhome? Link to comment Share on other sites More sharing options...
Guest Tracker Posted January 21, 2010 Share Posted January 21, 2010 Many years ago we too had a heating firm install a 9" airbrick about three feet from the new gas Baxi back boiler in our lounge. That lounge wall faced south west and in West Cornwall you can imagine how much nice cold wind that allowed in. As he finished making good the plaster he told us that the rules stated that under no circumstances were we ever to block or impede the airflow through this aperture as to do so would be dangerous. He then gave me a suitable sized offcut of marine ply to make a jolly good external cover saying that in his view our home had enough airflow and the rules were crazy. He also said that he would deny this conversation and that we should take the cover off prior to annual servicing. After trying various clip on and screw on methods to seal it I eventually siliconed the thing in place and painted over it and in all the remaining 10 years we lived there not one servicing engineer ever said a word! That was about 1978 and over the next 24 years or so we often visited the 'new' owners who had became good friends. One of the topics of conversation was always the cover and as of about 2003 the cover was still in place, the boiler had been updated, and the house nice and warm! The people who make the rules need to communicate better with the designers who need to communicate with the end users to create airflow without draughts if they want their rules to be followed? How hard can it be? Link to comment Share on other sites More sharing options...
michele Posted January 21, 2010 Share Posted January 21, 2010 Ok Ok .........So whats th epoint in having a flu over my head over the back bed then ? It dont stop nothing it just gives the oldman a stiff and he moans at me . I could understand if the gas was in or near the back bed . This is a great big flu and belting down it is freezing air thats rediculos its almost as if they forgot to put it in run out of space and just dumped it there , I end up opening the cupboard door over our heads and stuffing in a towel or something for the night . Besides I have not got the heating on at sleep time. Link to comment Share on other sites More sharing options...
Mel B Posted January 21, 2010 Share Posted January 21, 2010 Brambles - 2010-01-21 7:38 PM "Anyone thinking of blocking off ANY vents/areas must check that there are sufficient areas left unblocked to be safe." How does one go about determining what is regarded as 'safe' without knowing what the recommended ventilation area is required for a given volume of Motorhome? Common sense ... hopefully people have some of that ... if you don't feel you have any Brambles then please resist the temptation to do any 'stuffing'. :-S Link to comment Share on other sites More sharing options...
michele Posted January 21, 2010 Share Posted January 21, 2010 neck sorry , :$ Link to comment Share on other sites More sharing options...
colin Posted January 21, 2010 Share Posted January 21, 2010 Tracker - 2010-01-21 7:53 PM The people who make the rules need to communicate better with the designers who need to communicate with the end users to create airflow without draughts if they want their rules to be followed? How hard can it be? It's very simple, the vent is taken under the floor and brought up in front or to side of apliance, but most people don't want to pay for this so install a wall vent. Carbon monoxide kills around one person per week, one of the causes is people blocking off the air vent to stop draughts. Link to comment Share on other sites More sharing options...
Brambles Posted January 21, 2010 Share Posted January 21, 2010 Michele your typo did make me laugh. Link to comment Share on other sites More sharing options...
Peter Highe Posted January 23, 2010 Share Posted January 23, 2010 Hi Whether or not you block your vents, you must have a carbon monoxide alarm fitted. Ours has saved our lives when a faulty fridge tried to kill us! Peter Link to comment Share on other sites More sharing options...
Guest Tracker Posted January 23, 2010 Share Posted January 23, 2010 Peter Highe - 2010-01-23 11:24 AM Hi Whether or not you block your vents, you must have a carbon monoxide alarm fitted. Ours has saved our lives when a faulty fridge tried to kill us! Peter Fridges are supposed to be sealed from the inside of the van to prevent just this although most manufacturers seem never to have heard of this! However as fridge draughts are a major source of unwanted cold air it's always one of the first jobs I do on a 'new' van! Link to comment Share on other sites More sharing options...
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