Blown air heating systems

[HarryM1BYT]

A few weeks ago I tested the 2kw max electric setting of the blown air heating system and was not all impressed impressed with it, compared to a 2Kw fan heater. Mine has two outlets at the front, fed from the heater which is on the same side (nearside) as the outlets, with the duct run internally - then a third outlet in the large bathroom at the rear on the off side), which is fed via a duct which dives under the caravan floor for 3m before emerging in the wardrobe base. As the air emerged in the bathroom, it was little better than tepid, due to the heat loss from the duct. Under the floor, the cardboard duct had been run inside a second water proof duct, which provided some slight insulation, but obviously nowhere near enough.

Options were to insulate that long run of duct; divert the run so it didn't need to go outside in the cold to get to the bathroom; or forget trying to heat the bathroom at all via its own air duct.

I did the latter. I made a new hole for a new outlet in the far end of the side unit in which the heater unit is mounted, the end near the exit dor and the bathroom door, so it can at least blow its air towards the bathroom if its door is left open. The difference was quite remarkable - much warmer in the main area and the bathroom too.

Problem was, it recirculates the air - through heater, through ductwork, through the room and back to the heater. On its way through that 3m long duct outside, a lot of heat would be lost, so the net result was a cold, but well insulated caravan.

If yours has blown air installed they are good, but not if the ducts travel far out in the cold - what were the designers thinking of running 3m of warm air duct under the floor out in the cold.

[reworht]

I'm interested in this Harry, as I pick up my new (to me!) caravan a week come Tuesday. It's the first one I will have had with blown air heating - previous ones have simply had a gas fire - which to be honest, was pretty useless unless you were sitting on top of it!
I've booked our first few days away in it for late April, which can be quite cold, and I was obviously hoping that the blown air system would give me a much warmer 'van.
From what you're saying, and I totally understand the problem you've identified, I may not be that much better off/warmer
Did you give any thought to how, and with what, you may be able to insulate the underfloor ducting?

[HarryM1BYT]

Originally Posted by reworht

I'm interested in this Harry, as I pick up my new (to me!) caravan a week come Tuesday. It's the first one I will have had with blown air heating - previous ones have simply had a gas fire - which to be honest, was pretty useless unless you were sitting on top of it!
I've booked our first few days away in it for late April, which can be quite cold, and I was obviously hoping that the blown air system would give me a much warmer 'van.
From what you're saying, and I totally understand the problem you've identified, I may not be that much better off/warmer
Did you give any thought to how, and with what, you may be able to insulate the underfloor ducting?

Its my first blown air system on a van, but the uninsulted duct would seem to be a very common problem. Those in the know, seem to suggest 'Armaflex' is the best solution, apparently it is a sleave which fits over the top of the pipe - you have to take the pipe out, fit the Armaflex, then refit.

Some have the exit door, between the heater and the lounge area and if the heater is mounted on the nearside, there is no choice but to drop under the floor to get the duct across, so there is no choice but to insulate the duct.

In my case I think I could have reduced the length outside down to around four feet, but Bailey seems to have planned the pipe run to be outside as much as was possible. They ran it across the full width of the van, then back to emerge at the far end of the wardrobe - they could have saved two feet of pipe by simply putting the outlet in the nearest end of the wardrobe. They also ran the pipe directly across where the Al-Ko jacking brackets were designed to be installed, move the pipe to one side to fit the brackets and it is then very close to the revolving tyre.

It came with a spare wheel, on the Al-Ko carrier, except there is no accepted way to jack it up without a proper jack and the chassis reinforcing brackets. I was given a brand new Al-Ko jack last week and managed to win some brackets for 99p on ebay.

It was whilst struggling to fit the brackets, that I realised just how exposed the duct is to the cold and where all of the heat was going.

Is the blown air system worth having? I would say definately yes, providing you sort out any duct which runs under the floor. My heater runs 2Kw on electric and 3.4Kw on gas. You can run both simulataineously at 5.4Kw which would have made it really toasty even with the duct as it was, but it seems such a waste warming up the atmosphere. 5.4kw of heat, without the blown air system would make the heater and the cupboard it was partially mounted in unbearably hot, whereas the blower pipes the heat to the far ends of the van.

[reworht]

Thanks Harry - that's very helpful
You've also raised another thing I'll look out for - jacking points. Like yours, my new 'van has the Al-ko sparewheel carrier - so I'll need to have a close look at how to jack it up. On my ancient old Abbey I used a trolley jack on what was a substantial mounting where the axle tube met the chassis - but I daren't try that on the new one (a Buccaneer Elan 15 with an end washroom).

[reworht]

Harry - straying slightly from the original post - but still in theme !
From your knowledge of the jacking brackets/jack for the Al-ko chassis, does this http://www.ebay.co.uk/itm/Purpleline...item3f1e338895 look like the right kit to allow me to change a wheel?

[HarryM1BYT]

Originally Posted by reworht

Thanks Harry - that's very helpful
You've also raised another thing I'll look out for - jacking points. Like yours, my new 'van has the Al-ko sparewheel carrier - so I'll need to have a close look at how to jack it up. On my ancient old Abbey I used a trolley jack on what was a substantial mounting where the axle tube met the chassis - but I daren't try that on the new one (a Buccaneer Elan 15 with an end washroom).

I understand there are just two places where you can jack them up without the brackets - under the suspension arm or under the suspension tube which runs between the two sides, but only close to the wheel. Do not even attempt to jack it up via the chassis or it will simply bend.

Mine comes within the 1600Kg limit for the lighter jacking brackets, but have read of the lighter brackets collapsing in use, so I made a point of looking for the heavier duty ones. The HD version uses a bracket either side of the two sides (4 brackets). They both use the same main bracket, except the main bracket is reinforced with a web. I just fitted the main reinforced bracket and left off the other part of the bracket.

The two holes, one above the other for mounting the brackets, are located between the spare wheel carrier and the tyre. Don't attempt to jack a caravan up, unless it is either attached to the car, or with the hitch firmly attached to a solid object. I replace the entire jockey wheel unit with a bit of scaffold pole clamped in its place, which is set into a hole in my drive.

You would be wise to check out the spare wheel carrier - they are supposed to be checked out and serviced annually by the dealers as well as the spare tyre pressure checked. Mine has a full set of service stickers, but that spare wheel carrier had never been moved since it was fitted - which explains why I do my own servicing. They use a twin telescopic tube system, one tube intended to slide inside the other and it works well if serviced. I had to lash ropes onto it and lash the rope to a sledge hammer to get it to slide out - not something you want to be faced with when you have a flat at the side of a busy road. Once fully extended and the tubes properly greased it, it worked fine. The spare was unused, but the sidewalls were badly marked by the carrier frame, so I fitted some pipe insulation on the frame to help prevent it.

[reworht]

Thanks again
I had the same spare wheelcarrier on my old 'van, so I know what you mean.
I kept the telescopic sections well covered in Copperslip, which certainly helped in pulling them out - pushing them back in after checking the tyre pressure was a much harder task I found
My spare wheel was also marked where the bars had been clamped against the sidewall - luckily not sufficient to damage the tyre.
Currently got the carrier and spare wheel advertised in the local supermarkets - the new 'van has got both, so I thought I'd try and get a few bob for them - help pay for marinabrian's 160 re-map

[HarryM1BYT]

Originally Posted by reworht

Harry - straying slightly from the original post - but still in theme !
From your knowledge of the jacking brackets/jack for the Al-ko chassis, does this http://www.ebay.co.uk/itm/Purpleline...item3f1e338895 look like the right kit to allow me to change a wheel?

That looks like what is needed. It doesn't state a maximum weight rating, but it should be good for 800Kg per side.

[Alan.F]

thanks for the info harry i have yet to test mine in my new van

[RPWC]

When on site,I use a small fan heater, thermostatically controlled, you pay for your electric with your pitch fee,so why not use it,saves your gas.