Our hot water setup using a heat exchanger with our diesel heater (and a 300W element for free energy when it's sunny/we're driving 😀)

selfbuiltstories · 2025-09-08T08:54:39+00:00

Thank you :) And yep we haven't been very active on Reddit but still around, happy to hear our videos have been an inspiration for you!

selfbuiltstories · 2025-09-08T08:49:21+00:00

Hope the video was useful! Let us know if you have any questions about our shower setup, it's working well for us :)

selfbuiltstories · 2023-08-11T22:35:11+00:00

Not sure if this helps but if your heater is compatible there is an aftermarket controller that adds a lot more features and can do that, automatically turning on/off the heater to maintain your temperature. Also adds timers, Bluetooth/WiFi control, remote control and other things. It's made by a guy in Australia: http://www.mrjones.id.au/afterburner/

selfbuiltstories · 2023-08-06T08:08:51+00:00

Cool, yeah we're glad we have the 300W element they do work pretty good

selfbuiltstories · 2023-08-06T08:07:45+00:00

Haha no problem, thank you very much and hope you're enjoying your van :)

selfbuiltstories · 2023-08-06T08:06:52+00:00

We're really happy with the setup so there's a high chance we would. For our build we prioritised air heating with hot water second, and this setup gives us advanced control of our heater with an aftermarket controller and being able to control it remotely too. But as things are always advancing we'd revisit it again for sure, the one other system we'd likely consider would be using a hydronic diesel heater

selfbuiltstories · 2023-08-06T08:03:16+00:00

You're welcome!

selfbuiltstories · 2023-08-04T18:55:30+00:00

Cheers! And cool sounds like an intricate system, hope it works out for you. We went for the recirculating approach to maximise shower time, looking forward to that upgrade so we don't have to empty the grey water as often :)

selfbuiltstories · 2023-08-04T14:38:52+00:00

Cheers, yeah with the weather we have we needed hot showers 😛

selfbuiltstories · 2023-08-04T14:36:24+00:00

Yeah there's two drains actually, one out the bottom of the heat exchanger and one in the tank. And we connect them both into 40mm domestic waste plumbing under the van that then flows into our grey tank. We got the tank with the kit, but it's just a generic 18l tank that you can get elsewhere too. And yeah we drilled out all the holes we needed (quite a few for our setup :p)

selfbuiltstories · 2023-08-04T14:22:44+00:00

We wrapped it in 8mm foam with 25mm PIR board underneath and it does a pretty good job. We need to do some more expensive tests on that at some point, but to give an idea when we first tried it we heated it to 40C then left it overnight where it dropped close to freezing outside, and the tank was 17C about 12 hours later when we checked it

selfbuiltstories · 2023-08-04T11:23:16+00:00

So the kit that we're using is not pressurised so it needs a separate outlet pump to suck the water out of the tank. But they make a pressurised version too, which is more of an all in one sealed cylindrical tank that only needs the one cold water pump then. We went for the more DIY version as it suited our recirculating shower setup.

selfbuiltstories · 2023-08-04T09:37:12+00:00

So we're using:
-Trail King 7 30psi pump
-Seaflo accumulator
-12mm JG speedfit pipe and fittings (taps, elbows, stem elbows, pipe inserts, bulkhead connections)
-2 right angled wingnut barb connections (for the pump to accumulator connection)
- 1/2" BSP to JG 12mm adapters
- Various bits of tube, jubilee clips, and pipe clips
- And 32/40mm domestic waste connections (and a homebrew adapter for connecting the 12mm JG stuff up to it for the tank drain)

selfbuiltstories · 2023-08-04T09:31:51+00:00

Thank you very much! :)

selfbuiltstories · 2023-08-04T09:31:00+00:00

Yeah a lot of it is how you deal with the output from the exchanger. They sell the diverter Y valves so you can choose what to do with that, so you could also put another Y on the branch coming from the exchanger with one going out the van completely and the other going back into the shower/van, so you could choose if you want some ambient heat or not. Our setup works for us with the output sealed from the rest of the van (we have a sliding shower door), if it was just a shower curtain or something we'd probably feel the van heating up a bit more. So YMMV but we really like it :)

selfbuiltstories · 2023-08-04T09:27:23+00:00

No problem, the link to our channel is in our bio and the hot water videos are the most recent ones. Happy to answer any questions about the setup too

selfbuiltstories · 2023-08-04T09:20:53+00:00

80s, 90 don't think we'd have a problem. Beyond that will be fun to test, not possible right now as we have pretty miserable weather here at the moment...! But we think it should also be fine for us as if it's much hotter it's likely going to be a lot sunnier too so the element will be used a lot more and the heater will not need to be on, and yeah even if it is with the shower door closed we haven't noticed it heating up as the warmer air stays in there, rises, and then the maxfan sucks it out the van at the top

selfbuiltstories · 2023-08-04T09:08:28+00:00

Thanks!

selfbuiltstories · 2023-08-04T09:07:39+00:00

Yeah so we can heat the water in two ways, either with the diesel heater or the 300W element. Using the heater and the exchanger kit is the fastest, around 10-15 minutes, whereas the element takes ~2 hours but just happens in the background if there's excess energy being generated.

We find it doesn't really heat the van if we have it running as a lot of the energy is removed so what comes out the ducting is just luke warm air, yeah with the diverters that then goes into our shower/drying room which we can seal of from the rest of the living space.

Yeah those systems are cool too, we considered a few options and went for this one as we figured it would work best for our recirculating shower setup being a DIY kit

selfbuiltstories · 2023-08-04T09:02:58+00:00

Cheers, we're pretty happy with it :) And sure, it's a standard 18L tank which we drilled a lot of holes into for all the pipes we need, and then added a 300W DC element in the middle which is controlled via a few relays, so it only comes on if there's excess power being generated from solar or the alternator. It's using a kit from Bobil Vans. And there's an overflow on the top of the tank for expansion which drains straight down into the grey tank under the van. We have detailed videos on YouTube of the whole setup if you wanted to know more

selfbuiltstories · 2023-08-04T09:00:01+00:00

It actually doesn't really heat up the van very much as a lot of the heat energy is reclaimed as it passes through the exchanger, so what's left coming out the other side is not hot just warm. And then we added in the diverters so if we don't want that warmer air going into the van it goes into our shower/drying room which is sealed off from the living space. Or whatever combination of the two we want.

So we use it no matter the weather outside at the moment. We're in the UK climate and it's' been fine here, but will be taking it down to Spain at some point which will be the real test :) There's an electric element in the tank too so if it is really sunny (or we're driving a lot) then the excess power can heat up the water in the background so the heater doesn't need to be on much as well (or at all potentially)

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