DEFENDER2.NET - View topic - My Thermotop C install in a RHD 2.2 puma

↓ Advertise on Defender2 ↓

Home · FAQ · New Posts · My Posts · PMs · Search · Members · Map · Calendar · Profile · Donate · Register · Log In

Home > Maintenance & Modifications > My Thermotop C install in a RHD 2.2 puma

Page 1 of 3

Print this entire topic ·

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

My Thermotop C install in a RHD 2.2 puma

Thought I'd pop a post up to document my approach.

My budget didn't stretch to a new heater, so I traveled through eBay posts on the summer (seemingly a good time to buy!) And came across a Thermotop C with a wiring loom attached giving it a 12v trigger.

Was sensible bidding so I eventually won it for about £100. Turned up and the wiring loom was very poor, but someone had done the hard work of removing it from what appears to have been a Freelander and by creating a loom... Helpfully told me where to connect what.

Haven't got a photo of it as it arrived, but first job was to test it on its original loom to check it worked and worked reliably before stripping to rebuild.

Cue a bin of water, a tub of fuel, and a confused neighbour looking out their window seeing it steaming after a while.

Observations were that a) it worked. But that b) not as I wanted it to.

Problem being that after hearing cycle 1 where the bin water was brought up to temperature, it turned off the circ pump.

I want to be able to sit in the car with the engine NOT running, and be able to use the webasto to circulate the water whilst heating both the cab and the engine. No use if it trips off after one heating cycle and waits for the water in the heater to drop before it re-fires as my cab heater will go cold till the webasto drops.

So I needed a solution to that.

Turns out I think "normal" Webastos not bought as OEM parts are programmed to run the circ pump continuously. Either way... I needed a solution. More on that later.

Next step. Strip and rebuild.

Click image to enlarge

Click image to enlarge

.......with a strip of the water pump and a good clean. Think it had been running on a central heating radiator by the looks of the limescale. Cleaned off...

Click image to enlarge

Click image to enlarge

And a finished built up heater, with new gaskets and seals but the old glow plug as it was clean and working just fine.

Retested. All good. Save for the cutting out issue after 1 cycle.

My solution was originally to feed the 12v circ pump both from the on switch in the cab, and also from the heater supply. This would prevent the pump from stopping as soon as I turned off the cab switch and the heater not circulating water in its run down phase. But by doing so.... The heater also created its own backfeed to its own on switch. Ergo.... It would never turn off.

So I put a couple of relays in to isolate the feeds such that either the heater, or the cab switch can "command" the pump to run.

Then did a complete wiring loom replacement eye new wiring loom for it, and installed it on the heater with a P clip for safety and to stop the loom pulling on the terminals.

Click image to enlarge

Click image to enlarge

Ok.

Side note: the fuel pump it came with looked utterly terrible. Dented. Sprayed heath Robinson style. It worked. But looked terrible.

Click image to enlarge

Click image to enlarge

So at this point I ordered a Chinese knock off part for Webastos which turned up and frankly looks identical. It cost £15, delivered from China, instead of the £300 odd webasto want for their OEM part. I'd have liked a webasto one, but just couldn't afford it. So the Chinese copy part is ready to install. It's going by the tank anyway, so I can swap it out again later if it either fails or makes the heater swim in diesel.....

Ready to install the thing.

Now I wanted to install it up out of the wading depth as much as possible. Turns out mobile centre do a nice stainless steel bracket, powder coated black. £20 ish. Done saves hassle making it. Fits here..... (Photos from mobile centre)

Click image to enlarge

Click image to enlarge

And mounted to my heater....

Click image to enlarge

Now here's the issue.

And I have DEFINITELY given mobile centre the opportunity to comment here. So am just commenting as I find. I've had no response, so I'm guessing they're struggling with COVID and not getting to emails etc. Fair enough.

It doesn't fit on a puma. Not that I could make it do so anyway.

Problem is what's shown in their images is without the heater duct installed. If you install the heater duct, the webasto either hits the bulkhead, the top of the wing, or the duct. You simply can't miss all 3. The package space isn't great enough. It may fit on other engine variants. But it definitely doesn't fit on my RHD 2.2.

Click image to enlarge

Click image to enlarge

Once again.... I did contact mobile centre. But they didn't respond.

I couldn't see how mobile centre could help to be honest. There's no magic. It just didn't fit.

So.... Try not to cringe. I checked the heater duct. It's a thermoplastic. And frankly.... It's rubbish. There's so much volume at the top that's not needed. And I only needed another 30-40mm to get the whole lot to work.

Hot air gun and a glove handed push on the duct later and it's deformed into the inner volume enough that the heater fits and frankly has zero effect on the duct itself.

Click image to enlarge

Click image to enlarge

In it went. 4 holes all sealed with sealer through to the inner bulkhead edge. Sealer behind the bracket to stop it being a water trap and corroding the bulkhead.

All good.

So the next jobs:
1. Fit a fuel tap (thank you Badger superbly well timed offer of a fuel tank dipper).
2. Finish off my wiring loom and supply which goes into my homemade undercubby box with all my accessory wiring and fusing in it.
3. Order a length of webasto fuel hose which seems to be cheapest from ButlerTechnik and is the proper 2mm ID stuff.
4. Received a load of silicone heater pipework U and L shaped pieces and some L adaptors. Just gotta figure out which heater hose to cut!

Will update when I've done the next bit.

Last edited by Matt110 on 2nd Dec 2020 12:03pm. Edited 1 time in total

29th Nov 2020 5:25pm

BenB8man

Member Since: 22 Mar 2017
Location: Norfolk
Posts: 429

2010 Defender 110 Puma 2.4 DCPU Stornoway Grey

Love threads like this. Gives me some real encouragement to try things like this myself. Good work!

I'll be interested to see how you get the water to circulate as much of the cooling system as possible when its heating up. I'd love to have a system that heated the cab and the engine block together, with a remote option and way of running the cab blowers for a while.

Looking forward to seeing your progress.

29th Nov 2020 7:57pm

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

Cheers. In theory, it's passing water through the cab heater matrix as first priority and the. Back out into the block, through the block and back to the heater again.

I don't know the block entry and exit points for the heater matrix though to be fair.

They're installed like this to keep vehicles warm and heat the block up in -30 degree climates so should work.

Think there's several who have used them in very cold climes

29th Nov 2020 8:01pm

jst

Member Since: 14 Jan 2008
Location: Taunton
Posts: 8061

2011 Defender 110 Puma 2.4 USW Stornoway Grey

I have mine fitted same place as yours, same mod to ducting too!

Mines plumbed in to heater pipes so heats heater first if i remember correctly (if heater is turned up on puma.)

Std thermotop heats coolant and continues to circulate coolant. It also runs internal cabin fan if fan is left on, once coolant reaches a set temp. Cheers

James
110 2012 XS Utility
130 2011 M57 bespoke Camper
90 2010 Hardtop
90 M57 1988 Hardtop

29th Nov 2020 9:45pm

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

I feel SO MUCH BETTER knowing I'm not the only one that had to mod the ducting!

You've made my night! Am out here now trying to figure the hoses out and directions etc.

29th Nov 2020 9:51pm

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

Can anyone tell me which is IN to the heater and which is OUT?

Click image to enlarge

29th Nov 2020 10:16pm

BenB8man

Member Since: 22 Mar 2017
Location: Norfolk
Posts: 429

Pinched from another thread.

29th Nov 2020 10:29pm

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

Thanks

29th Nov 2020 10:30pm

jst

Member Since: 14 Jan 2008
Location: Taunton
Posts: 8061

^^ is correct and just checked mine, its plumbed after the heater (memory was wrong). mine is plumbed after the cabin heater but before the shower heat exchanger! reason being i wanted to warm the engine coolant to heat the block as a priority over a warm cabin, in fact on a cold drive i dont turn on the puma cabin heater until engine temp is 50deg C (Scanguage)

in the summer when camping its plumbed to go straight to the shower heat exchanger so i get max heat in shower water. Cheers

James
110 2012 XS Utility
130 2011 M57 bespoke Camper
90 2010 Hardtop
90 M57 1988 Hardtop

30th Nov 2020 9:14am

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

That sounds interesting. Which heater heat exchanger do you have for a shower?

I have this one that's been in our dad's ownership for a while but none of us know the number of fins or efficiency of it, and it's not adjustable in terms of flow. Was considering putting that into the system but it's got a fairly small inlet size at the minute which is not large enough to match the flow at same pressure as the Puma heater system and webasto.

With the fittings removed it then has sufficient diameter inlet and outlet but with the worlds wierdest thread - not either metric or imperial given i can't get any bolts to fit in it! Need to find a set of thread gauges to see what it is so i can get a larger diameter pipe fitting for the end of it.

Click image to enlarge

30th Nov 2020 9:55am

jst

Member Since: 14 Jan 2008
Location: Taunton
Posts: 8061

i have two, one in 110 and one in 130. think there a link in my 130 build thread, will look for it Cheers

James
110 2012 XS Utility
130 2011 M57 bespoke Camper
90 2010 Hardtop
90 M57 1988 Hardtop

30th Nov 2020 9:57am

jst

Member Since: 14 Jan 2008
Location: Taunton
Posts: 8061

https://www.defender2.net/forum/topic71658-165.html

page 11 or 12 Cheers

James
110 2012 XS Utility
130 2011 M57 bespoke Camper
90 2010 Hardtop
90 M57 1988 Hardtop

30th Nov 2020 9:59am

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

Firstly loving that build thread and your 130 - really is superb, have taken note of dogbox.co.uk for our own future rear end mods!!

I've extracted the photo - whats the box is that the heat exchanger unit? Any specs on what it was or links? Really interesting thing is i didn't dream that would package there and there would be space. There's more than you think!!!

30th Nov 2020 10:07am

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

Quick update after MobileCentre dropped me an email. They've sent me an additional photo which does look like the Thermotop they fitted with their bracket is different. Although I think the main length of the plastic covers at the top (which defines the overall heater length even if the casting is different) are the same. So still puzzling.

But all well in the end it's in and sorted. And it appears we have a solution in the heating of the duct and pushing out the way if anyone wants to fit it here. The bracket is top quality and can be positioned wherever needed on the bulkhead so see how you get on.

This is the one they fitted. Slightly different front casting I think.

Click image to enlarge

30th Nov 2020 5:14pm

jst

Member Since: 14 Jan 2008
Location: Taunton
Posts: 8061

heat exchanger came from: https://www.ebay.co.uk/itm/254152896655

took 3 days or so ordered at time i posted that thread. i went for biggest size they had listed there which was 125kw from memory and rereading the thread. but it could of been 85kw..... i would need to measure. i have a 125kw one in my 110 that i do know.

i ordered insulation box too - its gives a packaging option.

fitting most were 1/2BSP or 3/4BSP from ebay

i tried cheaper heat exchanger options they just didnt last. 110 one has been in there 10 years no problems. Cheers

James
110 2012 XS Utility
130 2011 M57 bespoke Camper
90 2010 Hardtop
90 M57 1988 Hardtop

30th Nov 2020 6:46pm

Page 1 of 3

All times are GMT

Jump to

< Previous Topic | Next Topic >

Posting Rules

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum