[dazmond]

My grippatank heater is wired into the liquid logic controller so every time I turn the controller on the heater kicks into life but I can turn the heater off on the controller so only the pump comes on if I want to use cold water(I never do though).....

[Jonny 87]

Well done!

It’s really impressive what you’ve managed to do.

[P @ F]

Well done!

It’s really impressive what you’ve managed to do.

Thanks Jonny , although my little mishap has done my head right in , I have managed to get the temps higher but at the cost of a slight drip within the chrome pipe , and the only way to get at it is to do a full strip down which I am a bit against as it was a right bar steward to get it together !
If the burner is going the heat dries the water out , but if it isnt then the drip will be a leak , and I dont do leaks !!
Im just gonna hope it lasts until I get Mk 2 sorted , much friendlier design 

[a900]

What’s the drip from?

[P @ F]

What’s the drip from?

Its from a 90 degree compression joint within the chrome pipe , the only way to get to it to nip it up is to strip the whole thing and remove the coil , its not leaking enough to warrant that just yet , and as Mk 2 is on the way I will just soldier on !

[a900]

What’s the drip from?

Its from a 90 degree compression joint within the chrome pipe , the only way to get to it to nip it up is to strip the whole thing and remove the coil , its not leaking enough to warrant that just yet , and as Mk 2 is on the way I will just soldier on !

It’s all a big experiment. Can’t expect any of this to work perfect first try. What sort of temperatures you been able to get now?

[P @ F]

From fire up  can get 30 at the brush head  with the usual  hose out , but with the mod I did over the weekend things didnt really improve that much , I wrapped the 5m coil around the chrome pipe in a bid to pre heat the water before it hit the internal coil , but at the time it was not insulated , I have foil wrapped and ally taped it up now so we will see what tha moro brings !
I do think that the most I will gain is to up the size of the internal coil , I only have 2.5m in there at the mo , I can get up to about 4m I  reckon  , if coiled better than this one , what I have now is just a mix of older parts all slung together , better results are a commin matey !

[P @ F]

Looks like I have hit the peak with the coils that I have!
Same ball park figures that I had the other day but that day ambient was 12 today it was 8
The picture is temp from heater and I was getting 40 at the brush head .

[a900]

That is impressive. What sort of input temperature Do you have to get that temp?

[P @ F]

That is impressive. What sort of input temperature Do you have to get that temp?

That is the problem , I was meant to be taking the tank temp after the picture , however , a custie came out and wanted to pay me !
I forgot to do it after that , but lets not forget that that temp was not on demand as such , it was using pre heated water from the return to tank setup , I only had about 75L left and it was after around 5 hours into the day , so its not all as it would seem , as it stands though , I know that whatever the feed temp is I am able to rise it by an average of 15 degrees .
These are results from when I did the backpack test I mentioned a few posts ago , input and output temps
15>34
26>43
31>46
34>48
40>53
45>58
50>62

Once I have got Mk 2 built with its 30% bigger coil I should have much better results , not that they are by any means poor so far , but the next and probably final step will be to swap out the 350 tank for two 175's.
This will massively boost my ability to have higher temp feed water much sooner , I will just decant from cold into hot as I need to .
If I can hover the feed tank at 40 then raise it to 53 after heater I should end up with at least 40 at the brush head , I would be more than happy with that !   

[a900]

What sort of temperature are you getting out of the exhaust? I’m Wondering if your stripping out most of the heat from the burner or if there is much left.

I wonder whether removing some of the aluminium air heat exchanger material off the burner or the external fan might encourage more heat down the tube (therefore giving high temp potentials) or whether it’s not getting super hot because the exhaust gasses are not being baffled around the inside of the air to air heatsink.

Are you feeding the cold water into the end nearest the exhaust or the burner end? For most heat transfer it needs to be exhaust end to progressively heat the water upto the hottest end.

After cleaning my webasto burner and replacing the steel mesh it starts up with very little smoke. I’m still running some waste oil and heating the fuel mix with copper tube wrapped around the hot water outlet (22mm copper pipe) with a thermal compound to exchange the heat. Hoping this will help the oil and diesel (soon to be kerosene mix) to cleanly burn for a long time without maintenance.

I’m impressed with how you’ve been able to adapt these Chinese air heaters for our usage. It’s funny I brainstormed how I could make the Chinese airheater work for me long before you revealed what youve done. I just don’t think I have the fabrication skills and thought I would end up spending more on specify heat exchangers.

Having seen what you’ve achieved I think for me I would like to be able to have 60-65 straight off to help me with conservatory roofs or facias and I’m not sure the Chinese air heater could output that sort of temp easily.

[P @ F]

They do an 8Kw version too , maybe I will look into that , but for now Im going to push this 5Kw to the limit to see what it can do !

[a900]

They do an 8Kw version too , maybe I will look into that , but for now Im going to push this 5Kw to the limit to see what it can do !

Well that was a comprehensive answer 😂😂😂😂😂

[a900]

This bloke is literally doing what I’m in the middle of putting together.

The webasto 90 exhaust size is larger so not able to find a bolt on EGR cooler but working on the one I’ve got.

Found out after planning to get my 77 year old grandad weld it together for me that it’s stainless steel. He doesn’t have a TIG to weld stainless steel. So the best option I could think off was to weld a bracket to hold the 2 adapters in place and job weld the seam to make it air tight. My grandad doesn’t weld so often now and his MIG wasn’t working right. So he Arc welded but it was a bit powerful and blew through hence not so neat. But should do the job.

Unsure if to preheat and feed the water pumps with the heated water from the EGR cooler. (Could get 2 hot if water doesn’t flow to the pumps for a while)

Or recirculated through the EGR and back to the tank. (More complicated as will require another little pump)

[P @ F]

My little addition which was the outer coil to pre heat the water did not do much in the grand scheme of things !
I think if you have the juice then you would be better off with EGR feeding back to tank , or a smaller tank with overflow as you mentioned before , the trouble with going back to main large tank is that if its too big then the gains dont benefit you until very late in the day .

[P @ F]

As it was sit at home weather today I decided to start Mk 2 , totally nailed it!
It’s all fabricated from scratch and ready for a few small welds to be done .
I’m going to be able to get about 26 coils in this one , the last one only had 13 as it was a rush job !

[a900]

Mate get as many photos up as you can. Like the way you’ve got it working

I thought about adding the EGR cooler into the heater coolant loop so out the heat exchanger into the EGR cooler then back to the reservoir. While a much simpler aproach, I wouldn’t draw as much heat out of the exhaust because the water will already be 60-80c.

As you say recirculating back to the tank looks like the way to go. I think I’m going to add a tee to the tank outlet to draw water off run a small pump to pump through the EGR cooler and feed it back to the tank. Either by running the return hose all the way internally down to empty the hot water near the outlet of the tank or t it back into the tank outlet.

Either way it means the pumps should be drawing warmer water than without the EGR cooler and if not the tank will get hotter anyway from the recirculated water

[P @ F]

Yes , with doing it as we are, we  are tailoring it to our own needs , what works for me may not work for another bloke due to his tank size and work type , I am stop start which means a fair bit of recirc is going on , Fred Bloggs who parks up and does a massive building a day can only hope for on demand temps , with what I am running now that means about 30 at the brush head all day for Fred , where as I cant jump to 50 or so !

I am hoping that coil numbers is a key factor here too , at the mo I have 13 and am getting a 15 degree rise , with any luck having 26 could give me a 25 degree rise above my ambient tank temp , who knows ?

[a900]

Yes , with doing it as we are, we  are tailoring it to our own needs , what works for me may not work for another bloke due to his tank size and work type , I am stop start which means a fair bit of recirc is going on , Fred Bloggs who parks up and does a massive building a day can only hope for on demand temps , with what I am running now that means about 30 at the brush head all day for Fred , where as I cant jump to 50 or so !

I am hoping that coil numbers is a key factor here too , at the mo I have 13 and am getting a 15 degree rise , with any luck having 26 could give me a 25 degree rise above my ambient tank temp , who knows ?

What size tubing you using again?

I recon you could get the most energy out with an old condensing boiler. They are designed to transfer as much heat as possible into the water.

Out of interest. How hot is the exhaust outlet from the burner after it’s been over the coils? If it’s hot I’m guessing there is till lots of energy to be had

[P @ F]

The chrome tube is 60mm and the copper tube inside is 10mm .
Got a pic of one of these condensing boiler jobbies ?
Still very hot , dont know for sure but much more can be done yet .
Mk 2 chrome tube is only 55cm , same as Mk1 , if I was to mount the other way in the van I could up the chrome to 1m at least !
Be looking at 50 coils then