Rear Heater - Night heater conversion

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cptsideways
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Rear Heater - Night heater conversion

Post by cptsideways » Fri Dec 18, 2015 9:19 pm

Hi folks, long time no Bongo but I'm back again

It would appear the rear heater is the ideal candidate to convert into a night heater. So my plan is to un-link it from the normal power circuit & power remotely off its own leisure battery & plumb it up to a Webasto 5kw thermotop water heater (The type used on many diesels as waterworks pre heaters)


I have much experience of the webasto's I use one for my conservatory underfloor heating its just the rear heaters in the Bongo I'm new too


So a few questions:

1) Where is the wiring linked to eg where does it go??
2) any relays I need to know about before I rip the entire van apart lol.
3) any idea the wattage of the rear heater motor?

ETA: Well done all that above & have come to an interesting conclusion.


I managed to power up the fan but it did some weird speed cycling, so I now have the front AC controller powered by my leisure battery on a switch as it appears the rear blower is digitally controlled. This allows the rear blower to be on & the front system off as such.

I have a 110ah battery so will see how long the battery lasts, so far its been running on the low blow setting for over 6 hours & no noticeable voltage drop. It is very quiet on idle enough to sleep in there fine.

Next part is to rig up the heater unit into the waterworks, I might be tempted to run the heater through the entire waterworks, which is what these are designed for. Or just the heater which would be quite simple, but there is a lack of water to circulate using that method.
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Re: Rear Heater - Night heater conversion

Post by mikeonb4c » Fri Dec 18, 2015 10:47 pm

Wow - member since 2004. Welcome back :-)

Very interesting you're using the water heating approach. I've often thought that might be used to provide a better heat than blown air option. It'd be great if the whole existing coolant system could be used - is that what you're thinking? If only a radiator could be placed where convection alone achieved circulation and gave heat out in the interior, fan requirements would be minimal. :roll:
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Re: Rear Heater - Night heater conversion

Post by g8dhe » Fri Dec 18, 2015 11:06 pm

The wiring diagrams may help you ....
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Re: Rear Heater - Night heater conversion

Post by cptsideways » Fri Dec 18, 2015 11:32 pm

Cheers, yes one of the first members I believe 8)

Thanks for the wiring diagrams, however I have it sussed :) Rather simply I might add.

I will leave it overnight running away to see how the 110ah battery copes, so far so good. It's been going for a good 8 hours currently. Am I correct the Climate versions dont use a resistor pack in the rear heater, as obviously that would drain a lot of juice if it did.

These are the heaters used on a lot of diesels, this one came from a Rover 75 but they come on all sorts of cars. They can be rigged to be triggered remotely this one used be on a plipper in my wifes Rover75. They will warm an engine to 65deg in about 20mins which is plenty for a toasty start on a frosty morning. My plan is to be able to take the Bongo skiing & -25deg outside is not unheard of, so 5kw heating running all day should keep the bus warm. They use about 0.5L an hour to warm up initially & 0.25l of fuel an hour once warmed up & ticking over.

I'll be adding a couple of 80w solar panels to the roof too to keep the batteries going, I have built in a 2nd 110ah battery but not sure if its needed at this rate.
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Re: Rear Heater - Night heater conversion

Post by mikeonb4c » Fri Dec 18, 2015 11:53 pm

cptsideways wrote:Cheers, yes one of the first members I believe 8)

Thanks for the wiring diagrams, however I have it sussed :) Rather simply I might add.

I will leave it overnight running away to see how the 110ah battery copes, so far so good. It's been going for a good 8 hours currently. Am I correct the Climate versions dont use a resistor pack in the rear heater, as obviously that would drain a lot of juice if it did.

These are the heaters used on a lot of diesels, this one came from a Rover 75 but they come on all sorts of cars. They can be rigged to be triggered remotely this one used be on a plipper in my wifes Rover75. They will warm an engine to 65deg in about 20mins which is plenty for a toasty start on a frosty morning. My plan is to be able to take the Bongo skiing & -25deg outside is not unheard of, so 5kw heating running all day should keep the bus warm. They use about 0.5L an hour to warm up initially & 0.25l of fuel an hour once warmed up & ticking over.

I'll be adding a couple of 80w solar panels to the roof too to keep the batteries going, I have built in a 2nd 110ah battery but not sure if its needed at this rate.
What I'm trying to work out is whether, since the Bongo is mid engined, the now heated engine block could usefully transfer its heat to the interior. We're no talking about baking heat here, just enough so that it is comfortable sitting and sleeping in the Bongo in cold weather. No fan would be needed - just natural convection/radiation.
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Re: Rear Heater - Night heater conversion

Post by cptsideways » Fri Dec 18, 2015 11:59 pm

mikeonb4c wrote:
cptsideways wrote:Cheers, yes one of the first members I believe 8)

Thanks for the wiring diagrams, however I have it sussed :) Rather simply I might add.

I will leave it overnight running away to see how the 110ah battery copes, so far so good. It's been going for a good 8 hours currently. Am I correct the Climate versions dont use a resistor pack in the rear heater, as obviously that would drain a lot of juice if it did.

These are the heaters used on a lot of diesels, this one came from a Rover 75 but they come on all sorts of cars. They can be rigged to be triggered remotely this one used be on a plipper in my wifes Rover75. They will warm an engine to 65deg in about 20mins which is plenty for a toasty start on a frosty morning. My plan is to be able to take the Bongo skiing & -25deg outside is not unheard of, so 5kw heating running all day should keep the bus warm. They use about 0.5L an hour to warm up initially & 0.25l of fuel an hour once warmed up & ticking over.

I'll be adding a couple of 80w solar panels to the roof too to keep the batteries going, I have built in a 2nd 110ah battery but not sure if its needed at this rate.
What I'm trying to work out is whether, since the Bongo is mid engined, the now heated engine block could usefully transfer its heat to the interior. We're no talking about baking heat here, just enough so that it is comfortable sitting and sleeping in the Bongo in cold weather. No fan would be needed - just natural convection/radiation.
I would say yes, as I have found it stays warm inside for a good two hours after a drive, if the underside was more blocked off than current then definitely yes. Not sure in proper sub zero temps it would though.
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Re: Rear Heater - Night heater conversion

Post by mikeonb4c » Sat Dec 19, 2015 12:05 am

Exactly what I was thinking. And it would be interesting to consider how readily the engine bay might be blanked off underneath (when parked up) in order to reduce cold wind stripping away heat. The undertray takes care of a lot to give things a head start. I like the idea of minimal extra electrical drain. Does the webasto diesel burner need any electricity apart from ignition?
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Re: Rear Heater - Night heater conversion

Post by cptsideways » Sat Dec 19, 2015 12:19 am

They do yes, there is a water pump & a pulsed fuel pump, fairly minimal though 18-26w, but that pump will do all the circulation you ever need. I have one running 40m of underfloor heating in the conservatory. Which at 5m by 3m is fairly big & worse than a bongo for insulation & it keeps that at a toasty 18deg in freezing weather.
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Re: Rear Heater - Night heater conversion

Post by mikeonb4c » Sat Dec 19, 2015 1:01 am

cptsideways wrote:They do yes, there is a water pump & a pulsed fuel pump, fairly minimal though 18-26w, but that pump will do all the circulation you ever need. I have one running 40m of underfloor heating in the conservatory. Which at 5m by 3m is fairly big & worse than a bongo for insulation & it keeps that at a toasty 18deg in freezing weather.
Wish I had your skills - I'd be installing one in mine!
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Re: Rear Heater - Night heater conversion

Post by cptsideways » Sat Dec 19, 2015 8:55 pm

Well - Bingo its working, 90% rigged up, still some wiring to finish but bloomin heck its rather good!!!

It took about 30mins to get up to a temp where noticeably warm air is blowing out of the blowers, current issue is there appears to be a LOT of Bongo waterworks that heats up first :lol: eg the header tank, rad pipes etc etc. I think my water circuit is working the wrong way round, ie I want rear heater first then the engine end, currently its around the other way, which means its takes 30mins to heat soak everything else first. Should be a simple fix.


But: Flippin heck its rather good, the rear controller is live & I can twiddle the temps/blow/direction from the back. Its just like it would be with a warm engine. Where is the thermocouple/stat for the rear or does it even have one?

I have mounted the Webasto under the left seat, I used the original bracket for the exhaust valve thingy to mount it all outboard of the chassis rail & the fuel pump. Just an exhaust to route & fit the silencers. Think I'll run a longer exhaust to vent near the waste water tank. Its currently plumbed into the waterwork pipe in front of the turbo by the block to the heater rail.

So I'd call that a successful project so far :) Will get some pics of the install tomorrow
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Re: Rear Heater - Night heater conversion

Post by g8dhe » Sat Dec 19, 2015 9:27 pm

The only temperature sensor for the cabin I have found and shown on the diagram is G3-15 to the right of the glove box, nothing else is shown.

but that is marked for the front cabin, I suspect that its a case of the normal slider just sets the position but doesn't actually have any feedback to control the temperature.
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Re: Rear Heater - Night heater conversion

Post by JoeC » Sun Dec 20, 2015 2:55 pm

cptsideways wrote:Cheers, yes one of the first members I believe 8)
You were the 42nd member.
http://www.igmaynard.co.uk/bongo/forum/memberlist.php
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Re: Rear Heater - Night heater conversion

Post by cptsideways » Sun Dec 20, 2015 5:45 pm

Install completed, except might have to re-route the waterworks in case I have plumbed it in backwards as such, a road test will prove that.

Or is there a diagram showing water flow direction for the Bongo's??


It also become apparent the air bleed pipe really needs a header tank!
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Re: Rear Heater - Night heater conversion

Post by g8dhe » Sun Dec 20, 2015 6:49 pm

These diagrams come from widdowson2008 threads http://www.igmaynard.co.uk/bongo/forum/ ... 49#p360049
but I always spend ages finding the right picture in the threads so keep a copy myself!
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Re: Rear Heater - Night heater conversion

Post by cptsideways » Sun Dec 20, 2015 8:36 pm

g8dhe wrote:These diagrams come from widdowson2008 threads http://www.igmaynard.co.uk/bongo/forum/ ... 49#p360049
but I always spend ages finding the right picture in the threads so keep a copy myself!
Image

Ahah - I have it tee'd into the blue 61-214 pipe, so its circulating the wrong way as I thought, well actually the right way but via the header tank & everything else etc, , mighty effective going that way haha
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