I keep running into a brick wall with a question!!!I can understand why with legal restrictions being what they are to day......but I would just like a straight answer from someone please. Let me put the question this way.....does anyone out there use their Truma gas heater while the pop-top is down?!? We travel down to Spain and sometime on the stop overs (without an electric hook up) it can get very cold at night - so top down, duvet on and water bottles plus leave the fire on low. I'm not asking for advice, unless anyone feels the need to venture some, just like to know if anyone does this.

Hymer's handbook specifically state you shouldn't use the van with the top down, inferring that it somehow upsets the ventilation. Given that it doesn't affect the ventilation through the vents in the floor, or your door (if the van has them) or the vent in the rear fixed roof, I can't see that it would be a problem. However, whilst we have dropped the roof during very high winds (The Great West Wales Hurricane in 2011 for instance), we've found that even on the coldest nights having a raised roof makes little difference to the internal temperature, providing some heating is on. Given that hundreds of thousands of Truma S300X heaters have been in use for decades throughout the world in caravans of all shapes and sizes and providing the burner etc has been checked annually by a certified gas tech. there shouldn't be a problem.

Add to all that that Hymer dealers are now selling insulating 'scarves' to clip around inside the canvas, does rather make their stipulation sound a bit OTT.

As you infer AK, probably based on lawyer advice to avoid any potential H&S risk.

Unless you can get Hymer/Eriba to tell you why they insist the roof must be up when occupied, which I doubt, you will need to make a common sense decision about; roof down/gas heater on!
My view, for what it's worth is, no risk, if usual vents not blocked (combustion air provided). These heaters have been installed in vans for years and they don't have to have their windows open if using them. If the heater is properly serviced, flue checked etc and carbon monoxide detector is working, no problem. The issue of gas producing high humidity is already covered in a previous thread, and you are more likely to get condensation on cold nights and on cold surfaces.
I'm sure some of the issue if having the roof down is caused by some over zealous H&S individual, I've met them in my previous working life, doing some sort of Risk Assessment and identifying possible injury, 'banging your head' etc, bless them!
My wife and I use a thermostatic fan heater overnight, many use small oil filled rads.

Colin

Oil filled roads and fan heaters need mains electricity and the OP is asking about places where no mains electricity is available.

There are none Roger, they rely on the standing ventilation built into the van, which includes gas drop-out holes and other vents in the floor and vents around rooflights (Heki's etc). What Hymer's translated manual refers to as 'forced' ventilation. In theory all the products of combustion on a S300x go up the flue.

You'll see that van gas boilers are room sealed and have a balanced flue outlet on the side of the van, pulling in combustion air via one half and expelling the exhaust via the other, so neither come in contact with the van's interior.

The only reason I've never left ours on overnight is the fear that the duvet hanging off the bed may come into contact with the heater. There are enough draughts in our van to keep body and soul alive.
Off on a slight deviation, does anybody know where these strange draughts that appear at the corner of the bed and under the benches come from?

If it helps, here is what the Eriba manual advises:

Poptop.PNG - Bild entfernt (keine Rechte)

I've just had a search of installation instructions for a Truma gas heater, granted I don't know the exact model and this is what I found.

Leadthrough for combustion air intake and flue gas discharge
"The combustion air is drawn in from the outside through the side wall via a flexible dia. 80 mm hose immediately behind the heater. The combustion air must not be drawn in from the interior. The leadthrough for the flexible hose of the combustion air intake connection must be drilled at the prescribed minimum height of 400 mm (distance between middle of holeand floor at installation location)...."


So, the heater needs it's own combustion air and must not rely on that of the vans air!

A sort of long drawn out balanced set of flues. Room sealed being another often used description. In other words if installed properly neither the combustion air nor the exhaust air is from or enters the van. The heat comes from convection from the metal heat exchanger fins in the heater.

Yep, I can understand the Eriba manual with reference to the gas hob. But, whilst preferable to have the top up it is not so essential for the Truma heater.

There are fixed ventilation vents under all the benches and gas drop-out vents under any gas appliance and/or gas controls. A caravan is designed to leak to keep air moving, reducing the risk of condensation, asphyxiation and death.

Yes Mr Randa, the draughts ARE odourless. They actually feel like a small howling gale rattling around the end of the bed encouraging me to keep all limbs under the duvet for fear of frostbite. Only thing that staves off the cold is more alcohol although the medical journals seem to disagree, but what do medical experts know about anything?

Hi Andrew, In answer to your question we leave the fire on with our top down. During the snow last weekend it was on for two days, albeit low. We do turn it of whilst sleeping though.