KAM
Well-Known Member
Has anyone tried forming the normal round pipe into an oval shape. Got a tight space to go through.
Hot air heater ducting
- Thread starter KAM
- Start date
pcatterall
Well-Known Member
Yes, no problem.
KAM
Well-Known Member
OK thanks for that. Presumably it's better if it's fully stretched first.
pvb
Well-Known Member
Don't deform it too much or you'll introduce extra resistance to the airflow.
LadyInBed
Well-Known Member
I would have thought the opposite. Measure the length you want to deform then squeeze and squash. I think doing it that way you will get a more uniform distortion.
Daverw
Well-Known Member
Just deform rather than squash keep the cross sectional area the same and flow will be ok
KAM
Well-Known Member
I thought if it was fully extended the depth of the corrugations would be less. Lower "I" value in the wall therefore easier to bend.
cpedw
Well-Known Member
That doesn't work - for a fixed circumference, a circle is the maximum cross sectional area. Any distortion from circular will reduce the cross section so keep it as near circular as possible.
Derek
oldmanofthehills
Well-Known Member
Its not optimum as any squashing restricts airflow, but we needed to do it to upgrade our 60mm pipe to 75mm when upgrading from ebispaker D1 to D2 model. However I think it might have been better to make great big hole in bulkhead and routed pipe a different way as I am not quite satisfied with flow.
This winter I am not quite satisfied D2 is powerful enough either but that's another matter
This winter I am not quite satisfied D2 is powerful enough either but that's another matter
dom
Well-Known Member
The aerodynamic problems associated with the corrugated Eberbasto type ducting are well documented. I found that large flow improvements could be made by straightening out sections of the hot air piping and switching large portions of it to suitably heat rated smooth silicone pipe.
You may find that the better airflow -- perhaps combined with better insulation -- allows the heater to work harder and not constantly slow down due to excess temperature. Or you may find a bigger heater more suitable, FWIW I use an 8kW on a 50' boat, far to big for temperature maintenance, but great for heating up quickly.
oldmanofthehills
Well-Known Member
I quite agree about the corrugation being unhelpful particularly on any length of run. Our Westerly has 100mm pipe under a metre long and driven by a D4 (4kW) it has massive flow. Usual ebi issues starting but then its great. Sadly less satisfactory on our LM27 with 75mm pipe as has heater at stern and thus 3.5m away from nearest outlet and 4.5 to furthest
I flinch at the cost of changing to 75mm silicon , but we are inadvertently heating engine compartment, locker, fuel tank area, and under fridge space so it might be worth trying. Perhaps if someone buys our Westerly - very well equipped and going cheap ?? Mind you then I would change to a D4 even if I couldn't get 100mm all the way, as D2/2kW is not very warm mid winter for heating a mostly uninsulated boat
I flinch at the cost of changing to 75mm silicon , but we are inadvertently heating engine compartment, locker, fuel tank area, and under fridge space so it might be worth trying. Perhaps if someone buys our Westerly - very well equipped and going cheap ?? Mind you then I would change to a D4 even if I couldn't get 100mm all the way, as D2/2kW is not very warm mid winter for heating a mostly uninsulated boat
dom
Well-Known Member
One other idea, I introduced a combination of Y- and T- junctions close to the heater to service the rear cabins and one bathroom that I convert into a drying hotroom in winter. If you could find a way of t-ing in a new outlet to somewhere useful close to the heater, it might be cheaper and less hassle way to increase airflow than boring for bigger ducting and full re-piping?
Just a thought, which no doubt you've had.
Just a thought, which no doubt you've had.
KAM
Well-Known Member
Did you find any suitable alternative materials. I have a long straight run to do and had been thinking of rolling my own using very thin aluminium sheet. I couldn't find any ready made thin wall tubing.