no hot air vent in back, can one be added?

[HNB]

hi guys, i have a bailey ranger s5 540/6 which has the triple bunk layout at the back.

now i have noticed a bit of a design flaw (imo)

there is a blow heater vent in the front seating area and 1 in the bathroom, but there is not 1 in the back for where the kids would be.

it would be nice to add 1 in, but i can not see a decent route in which i could do it, no where i could run the pipe through.

has anyone done this, if so what route did they use etc?

thanks,H

 

[Jaydug]

Where would you take the hot air from to feed a third outlet? The fan on the back of the fire has only two outlets - usually with a shutter device between the two to give priority - with one feeding the front of the van and the other, the rear. Tee pieces are available so you could tee off the rear pipe going to the bathroom. On my van the ducting goes from the fire then under the floor to the bathroom, with the under-floor part in thick insulation.

 

[Raywood]

If there is no sensible route from the toilet then most firms take them through the floor and back up where they are needed. You do lose some heat this way but insulation helps if it becomes a problem. I do not know of anyone doing this to an existing caravan. so have no first hand knowledge of how to do it. Most dealers will be able to supply the parts fairly cheaply I would think if you want to do it.

 

[HNB]

My idea was to use a T piece and tap into the bathroom heater,but there is no way to route it from the bathroom,unless like you said,i route it underneath.

That is the only option i had thought of, put underneath and use insulation on it.

Where is best place to buy these parts?

Thanks

 

[Raywood]

The parts including a T piece should be available at most dealers who can possibly give some advice as well. You could also try Amazon and e bay.

 

[ProfJohnL]

Hello HNB,

I have tried to find a picture or diagram of your layout without success, so I can't off detailed advice, but there are a number of points I would like to bring to your attention.

The most important question is whether such an extension will actually work. Hot air systems area good solution for shorter caravans, but as the duct length grows, it compromises the ability of the fan to blow the hot to its furthers point, so even if you can extend to that distance will it produce any warm air at the furthest out let?

The principle factor here is the pipe exerts drag on the blown air slowing it down, The long the pipe the more drag and the greater the loss of velocity. Its one thing of the pipe is straight, but for every 90 degree bend in the pipe, its the equivalent of adding and about an extra meter to the straight pipe length. Obviously any other air outlets along its length will also rob flow to the extreme end.

The slower the air is moving through the pipe the greater the opportunity for it to loose its heat through the duct walls.

Unfortunately is no simple formula to predict the effectiveness of an outlet of the type you are proposing, but there are some generalised ideas.

Keep the ducting as straight as possible and avoid sharp bends.

If possible keep the ducting inside rather than out to reduce waste heat losses out side. It may worth thinking about running a duct along the bottom of an inside wall and arranging to box it it to protect it - some manufacturers used to do this on side dinettes.

If it has to go out side, it is essential to ensure the duct is contained in a waterproof jacket (Truma used to sell a waterproof outer duct) and it is obviously a good idea to insulate it. There is a dedicated elbow for going through the floor, but its not essential.

https://dealernew.truma.com/_anweisungen/Truma_Katalog/pdf_verzeichnis/40_000/40000_35300.pdf
IF air flow is weak, Truma sell a "TBM Multivent Fan" See item 15

https://www.truma.com/int/en/heating/accessories-s-heaters.php
https://www.truma.com/downloadcenter/multiventtbm_installation_instruction_de_gb_fr_s.pdf
which can be added to a length of duct to assist air flow.

 

[HNB]

Hello HNB,

I have tried to find a picture or diagram of your layout without success, so I can't off detailed advice, but there are a number of points I would like to bring to your attention.

The most important question is whether such an extension will actually work. Hot air systems area good solution for shorter caravans, but as the duct length grows, it compromises the ability of the fan to blow the hot to its furthers point, so even if you can extend to that distance will it produce any warm air at the furthest out let?

The principle factor here is the pipe exerts drag on the blown air slowing it down, The long the pipe the more drag and the greater the loss of velocity. Its one thing of the pipe is straight, but for every 90 degree bend in the pipe, its the equivalent of adding and about an extra meter to the straight pipe length. Obviously any other air outlets along its length will also rob flow to the extreme end.

The slower the air is moving through the pipe the greater the opportunity for it to loose its heat through the duct walls.

Unfortunately is no simple formula to predict the effectiveness of an outlet of the type you are proposing, but there are some generalised ideas.

Keep the ducting as straight as possible and avoid sharp bends.

If possible keep the ducting inside rather than out to reduce waste heat losses out side. It may worth thinking about running a duct along the bottom of an inside wall and arranging to box it it to protect it - some manufacturers used to do this on side dinettes.

If it has to go out side, it is essential to ensure the duct is contained in a waterproof jacket (Truma used to sell a waterproof outer duct) and it is obviously a good idea to insulate it. There is a dedicated elbow for going through the floor, but its not essential.

https://dealernew.truma.com/_anweisungen/Truma_Katalog/pdf_verzeichnis/40_000/40000_35300.pdf
IF air flow is weak, Truma sell a "TBM Multivent Fan" See item 15

https://www.truma.com/int/en/heating/accessories-s-heaters.php
https://www.truma.com/downloadcenter/multiventtbm_installation_instruction_de_gb_fr_s.pdf
which can be added to a length of duct to assist air flow.

thanks for the reply, some very good info and points made, some i had thought of.

my main thought had been about the reduced strength of the flow as you pointed out.

when i was coach driving ( a bit off topic here but...) my coach had problem with the heating at back, there was not enough power to push the water flow, so extra pumps where added to help it flow through through, which is what i thought could help in this situation.

there is no possible way for it to run through the inside, so it would have to run underneath unfortunatley

 

[jignc]

If you are mainly on EHU buy a small fan or better still an oil filled heater and use that at the rear. 500 watts or even less should be fine so as not to overload the system.

 

[Dustydog]

Very interesting Prof.
I didn't know a supplementary fan was available. Thank you.
We go away a lot in the winter and find using gas as well as electric gives the heating a great kickstart and soon warms up all parts of the caravan.

 

[Craigyoung]

If you are mainly on EHU buy a small fan or better still an oil filled heater and use that at the rear. 500 watts or even less should be fine so as not to overload the system.

I agree with jignc , save all the agro and work and pulling things apart and buy a small heater and just plug it in at the back , won't take long to heat up id off thought

Craig

 

[biley_adam]

We have the S5 Pageant Bretagne 6 berth with 2 fixed rear bunks, and our rear outlet travels from the back of the fire, under the van and out under the bottom bunk. So will be pretty straight forward.

 

[ProfJohnL]

If you are mainly on EHU buy a small fan or better still an oil filled heater and use that at the rear. 500 watts or even less should be fine so as not to overload the system.

I agree with jignc , save all the agro and work and pulling things apart and buy a small heater and just plug it in at the back , won't take long to heat up id off thought

Craig

I agree, It will far cheaper . You can get a perfectly functional fan heater for around £20. You may already have one!
By comparison the parts for doing all the ducting will probably approach £50 or more.The fan heater can be used anywhere in the caravan or even at home.

 

[otherclive]

Agre that a supplementary electric heater would be better option and gives you more heating available if it is very cold in winter. Assuming the EHU can provide the amps. In my experience fan heaters can be a bit intrusive with their fan noise and I would recommend a small oil filled one. Under 500 watts should be adequate combined with the Truma. The only negative is the oil filled will be heavier than a fan. A convector sits half way between in weight but I wouldn't have one as they seem a bit flimsy.