"-15 Degrees" Heating System (Part 1) - The Cravats

Another interesting parcel! All the way from the USA!

This time it’s bits for a “-15 degrees heating system”. Neither of my Ds - my previous 1969 ID19b, nor my current 1968 Ds21  - were fitted with electric rear screen demister elements. I think they were introduced in 1969?  From 1963 (?) right through to 1975 however, Citroen had offered the option of a -15 degree heating system.

The set-up is intended to improve driving in colder climates. As well as a blind (a flap) in the aluminium air chute (to prevent the radiator from pulling in cold air, and so causing the engine to heat up faster)……

Part 5 is the lever of the 'blind' in the chute. Part 4 is the control cable

…….it also included a coolant fed, hot air blower in the rear of the car. Luxury!

Rear heater. In particular, note the part numbered "15" there......

The blower fed warm air to the rear passenger area but also up and onto the rear screen to de-mist.  It’s an extension of the conventional heating system and circuit. Rubber coolant hoses pass through the bulkhead from the engine bay into the cabin. They run along inside, and then outside, the sills to the rear of the car, then under the rear seat to where the heater and blower are located.

Coolant hoses under the rear seat
(Copyright "Nuancier" website)

It isn't obvious from the exploded diagram in the workshop manuals, but the main heater matrix, blower and tubing is situated behind the rear seat back – extending slightly into the boot.

Rear heater unit mounted behind the rear seat
(Copyright "Nuancier" website)

The rear seat  base is different to a standard seat to allow room for water hoses and warm air ducting. (sometime ago I put some photos of this up on the ‘Useful Information’ tab of this blog for somebody).

This optional heater system was intended/ expected to be used on cars in colder climates – UK, Scandinavia and Canada for example, but was also an option in France. Many years ago, maybe 1995, I’d bought one of these -15 degree heater system from Mick Groombridge over at the now defunct ‘Doctor Chevron’ near Soham. I think I’d seen it fitted to one of the scrapped cars languishing in his yard: a (black?) RHD, 1969 DS Pallas with a lovely slopey dash. It was somewhere over there.

That could just be my fanciful imagination of course. ANYWAY, the car eventually disappeared and (whether it was from that car or not……) a heater system was salvaged by Mick. £30 changed hands.

There was a big pile of bits. Back then I wasn't sure how this jigsaw puzzle went together. On a trip to 'Retromobile' over in Battersea, I asked whether any of their cars for sale might have a heater fitted - so that I could take a look. There was nothing on site, but one of their customers cars - at that time over at the bodyshop they used - DID have a heater. A phonecall of introduction was made  on my behalf and, grateful, I  arranged to nip over and take a few photos. The car was a blue, right hand drive frogeye with a 'natural' leather interior. It had a wonderful "used and appreciated" feel to it. I often wonder whether it's still on the road. Here's a few of the blurry photos I took that day:

"-15" system - under-bonnet coolant hose routing

feed hose pass behind the engine........

....and a black pipe carries the hose through the bulkhead.
Can you see it?

Back home I did a stocktake. I’d got just about all the parts. Including, crucially, the bit that most people fail to salvage - the special-shaped rear seat. The only bits unaccounted-for were the short black metal ‘S’ pipe that carries the hose through the bulkhead behind the exhaust manifold (rubber hose would melt and/ or perish in that location)........

A better photo of that black 'S' pipe
(Photo courtesy of Graham Hersey)

.......and two covers, or tunnels, for the hoses where they emerge from the sills in the back of the cabin. I had the carpet covers for them just not the metal tunnels themselves…..

Coolant hose to rear, without cover
(Copyright "Nuancier" website)

Coolant hose to rear, with cover. Much nicer
(Copyright "Nuancier" website)

The parts catalogue calls the covers DS 642-18 "Protecteur des tubes de detour d'eau et alimentation"........which (Google) translates as "Protector of water detour tubes and food". The “Nuancier” webite simply calls them ‘cravates’. 

Now when you hear 'cravat', you probably instantly think of Jason King..... 

The very wonderful Peter Wyngarde (RIP)

I know - we all do. But of course 'cravates'.........

........translates into English as 'neckties"........ You can see why Nuancier would call them that, as they do look a bit like neckties.

A necktie

A protecteur des tubes de detour d'eau et alimentation

Back in the 90s I’d simply used domestic 15mm copper water pipe to replicate the black pipe through the bulkhead, and had fitted the system in my DS21. I followed the workshop manual circuit diagram to wire in the appropriate switch for the blower. Both the heating and de-misting worked very well. I'd all but forgotten that I’d had someone make me two covers/ tunnels for the hoses. It had been guesswork based on the shape of the carpet covers. 

Fast forward to 2014. With a restoration underway, I’d been looking for the proper parts – particularly the tunnels - but they are hard to track down and in demand. While browsing I’d seen some on a table at Citromobile in 2018 and dived on them. 

'On sale' at Citromobile 2018 - two cravats from a "-15" set up.......

Only to find that they had already been sold (together with some other incomplete and tatty condition heater parts) for 600 Euros! So why were they on the table then.....

Sold at Citromobile 2018 - tatty rear heater of a "-15" set up.......(upside down)

At the start of this year another CCC member, with a recently acquired car, had said he was minded to pull out his unwanted and incomplete heater system. From what he told me, his heater seems to have been ‘hard-plumbed’ with runs of copper pipe instead of hoses. I was interested, but it turned out that his system already lacked several pieces – including the ones that I needed. Anyway, he has since decided it’s simpler to leave in place, with a view to maybe getting it working one day.

I had another near miss in Spring this year. I noticed that a car on Facebook and being scrapped in Canada(!) had the telltale signs of a -15 heater system: additional rubber coolant hoses under the bonnet. The car sold. I got in touch with the buyer. Unfortunately  the parts I was after were the same parts he wanted to salvage for his own car(!) – so no sale.

Telltale signs: the hose from heater goes back towards the bulkhead 

Soon after, a stroke of good luck. Again on Facebook, John Nielsen over in the US was offering a mixed bag of bits and pieces for sale. I wouldn’t normally have bothered looking (the parts were in the US!), but it was a Sunday night and I was bored. I’m glad looked. 

The advert didn't look very promising.......

I clicked through a couple of photos and up popped an image of some "-15" heater parts!! Not many at all but, crucially, they included the bits I was interested in.

Mixed bag of heater bits......

John was hoping to sell all the heater parts together, but I only really needed a couple of the bits. The cost of purchase and postage to the UK for the lot would have been prohibitive- especially for bits i didn't need.. After a day or so, and with the parts being incomplete and with no other better offers, John agreed to split the bits he did have and a sale was made. Getting them to the UK wasn’t cheap. As well as the cost of the parts, there was postage, duty and then VAT on top of the whole lot! Plus Parcelforce then charged me for the privilege of collecting the tax owed.

So anyway, at long last, here they are.

Not much to look at are they.....? 

The black pipe doesn’t look anything special, but it’s the pucker part.

Pipe dreams.....

Interestingly (well I think so!). It’s internal diameter is a little different to the two short ‘gris rose’ coloured metal tubes used elsewhere in the "-15" system. Not sure why that would be.....Thicker walls = stronger part for under the bonnet?

A whopping 0.5mm difference in internal diameter

But the real prize was the pair of Protecteurs des tubes de detour d'eau et alimentation''. As recently as June 2019 I'd been having conversations with Jamie at DS Workshop about getting a pair made up from a single example that he kept as a template. Here’s a comparison between the ones I originally had made back in 1995, based on guesswork and the real deal.

Original cover (bottom) and my early attempt at a copy (top)

Not bad length-wise. I got the profile of the end on the right hand side of my photo just about right as I was able to have a good feel of that on the other car back in 1995........

Copping a feel: top end of the hose cover in the rear footwell

But you can see that the real covers have a wider, flatter, and pointed lower end - presumably because they need to cover the large opening in the sill behind the drivers seat. Anyway, as a result, they DO look remarkably like neckties......or cravates.

For the moment I’m just going to stick these in a box with the rest of the "-15" heater bits. I’m sure I’ll write more about the “-15 “ system when I get to that stage of the rebuild.