Installation of Propex HS2000 in a 1974 T2 Bay (Dougal)

Installation of Propex HS2000 in a 1974 T2 Bay (Dougal) by Mark Henley


We purchased our van “Dougal” just over a year ago having been VW Beetle owners on and off for a few years. My wife and I attend music festivals as part of Oxfam’s festival team and having camped in a small 2-man tent, we felt we deserved some luxury, plus getting in and out of the tent at 57 was taking its toll on my knees – hence Dougal appeared.

Dougal was everything we wanted, if we had a hook-up, we would take a small fan heater and all was toasty and cosy, especially in that last hour or so before you get into bed, and in that first hour when you wake. Without a hook-up life was not so rosy (but infinitely better than a 2-man tent) so we decided to invest in a Propex Heater HS2000. I ordered it online as a kit and it arrived within 2 days for me to fit over a year later – it was a job I left on the backburner 🙂 (Sorry).

Mainly as a result of Covid-19, I have time and the motivation (not being bored) to install it. Like most blokes I’m a great one for not following procedures, but broadly I followed the supplied instructions, which were in fact a help. Below I have added some other bits and pictures which I hope will help anyone else with time on their hands to do this. I installed it under the rock and roll bed (which is what many people do).

Step 0 – Tools, Bits and Bobs

Review the kit contents and make sure you have the right tools for the job.

The kit will have components for a gas connection from a gas bottle to the heater, however you may already have a cooker and/or a refrigerator that already runs from your bottle. If this is the case, you will need a t-piece or a small manifold to ensure the heater has a supply without affecting other appliances. If running a large number of appliances, then you may want to switch to Propane which runs at about 30% higher pressure than Butane (but a bottle doesn’t last as long) – a Propane regulator is supplied with the kit.

There are no 8mm gas pipe fixing clips supplied in the kit. You will need to have a handful of these to fix the 8mm copper pipe to the sides of cupboards or the floor of the van (to keep the pipe where you want it).

A minimum of jubilee pipe clips are supplied in the kit but it was two less than I needed – buy some!

PTFE tape is useful for a good gastight seal on threaded fittings.

You will be cutting 2 x 40mm holes in your van floor, it would be a good idea to buy 2 x 40mm grommets to put around the sharp metal edges.

High temperature sealant.

Wire strippers/crimpers would’ve been useful, but I managed with pliers.

A good electric drill is a must!

95mm and 40mm hole saws are needed for the air vent holes and the exhaust/air intake holes.

A small gauge pipe cutter is a must if you want a good compression seal.

A multi-meter or one of those light-up screwdrivers will be needed to test your electrical installation.

If you haven’t got a spare switch on your domestic panel then a switch to isolate the unit electrically is a good idea (some people have seen a bit of current drain when the unit has been connected directly to the battery).

An 8mm gas isolation valve (ball type).

In hindsight I wish I’d bought a small gauge pipe bending tool – much easier than trying to bend the pipe around the outside of a coffee mug!

A coat hanger (all will become clear).

Step 1 – Preparation

Empty your van!

Remove anything from under the seat/bed. Remove the bedding/cushions (the bedding might need an air anyway). 

Remove everything from the cupboards between the bed and the side of the van. (In fact, remove absolutely everything from all your cupboards because its time you had a sort out – there won’t be as much room for storage under the bed with a heater there!).

Remove the gas bottle from its locker/cupboard to somewhere out of the way.

FIND SOMETHING TO HOLD THE BED UP WITH! (Or buy some large plasters for your head).

Step 2 – Safety

The battery was disconnected. I have a starter and a service battery so I disconnected both. I’d be drilling some big holes later on and messing about with the main control panel. Safety glasses are a must when drilling or working under the van. Thin rubber gloves aren’t essential but good to have also.

Step 3 – Where shall I put it?

I had already decided on a suitable location for the heater. The only viable location in Dougal was in the bed box so I crawled underneath and using the 4 bed frame bolts as reference points I found a suitable obstruction free area in which to drill pilot holes for the exhaust and air intake pipes. I drilled a small test hole – which is a very good idea as I’d managed to get the front/back the wrong way around when I was underneath, and the test hole came out somewhere I didn’t expect it!

Having drilled the pilot holes in the right place and filled the previous test hole (and checked underneath again) I had a crisis of confidence. Do I really want to drill 2 one and a half inch holes in the bottom of my pride and joy?

One quick pep-talk by the missus later and it was done. No going back now.

Why do the holes need to be 40mm wide?? I have looked online and there are a few reasons offered – so you can attach the pipes and jubilee clips from above seems to be a popular one (I tried that and it didn’t fit), to give you wriggle room if your measurements are a bit out is another, to give space around the hot exhaust pipe perhaps (which makes sense because of the heat), or to act as a drop vent for any future gas leak maybe (that also makes sense as the heater is installed slightly off the floor). Whatever the reasons I stuck to the instructions, but emailed Propex for a view. [Since writing this they confirmed 40mm holes give a heat safety margin. Propex also stated the holes can be filled with high temperature sealant but that in line with good safety practice, a gas drop vent is needed].

To finish the holes off I coated the insides with a little wood preserver and a touch of anti-rust on the edges of the metal floor pan.

It’s possible at this point to fix the heater to the floor using the brackets and screws provided but my preference was to leave that until I knew everything matched up (it better had – I’ve just drilled 2 bleeding big holes in the floor!).

Step 4 – Power and Control

The kit comes with 2 looms – one for power (12V dc), and the other for control via a switch/thermostat control box.

Dougal has a domestic fuse panel and switch bank to the rear which had a spare switch (marked “spare” so I knew it was spare). I would advise using a spare switch if you have one or fitting an isolating switch to the heater as some people have reported an amount of “leakage” which has slowly run the service battery down.

To access the fuse panel and the rear of the switch panel required disassembling the rear storage cupboard, the pieces of which were carefully stored with corresponding screws for ease of re-assembly.

The fuse panel has a 12V DC bus so instead of using the fuse holder supplied, it was easy to utilise an empty position on the panel which was then wired to one side of the spare switch. The other side of the switch is used by the positive lead on the power loom. The 5 Amp fuse supplied was inserted into the fuse panel.

Now for the hard bit – feeding the 2 looms through the bottom of the bed box, through the water tank store and through to the back where the fuse panel/switch terminals are. A hole already existed for other electrical wires on the floor of the bed box where it enters the cupboards, however it was not large enough to allow an additional 2 sets of wires through, and there wasn’t room for a small drill, so gently using a chisel (actually not so gently) the hole was enlarged to allow the plastic thermostat connector and power feed to pass through (Arghhh – after doing this I subsequently found out that the plastic connector can be detached and reattached to the wires – making the job a tiny bit easier!).

In order to pull the wires through to the back I used a straightened coat hanger which was pushed through the small hole for other wires going to the back, the power and control leads were taped to it and then pulled through. Of course, if you want to do it the easy way and feed the cables from the back to the front then feel free!

The power cable ends were terminated appropriately and the red one fed to the “spare” switch, the black one to earth.

At this point I decided to test the power connection. You could leave it until the end but testing it at this point would a) prevent a lot of rework later on, and b) give you a reasonable feeling that you know you are doing ok!

I reconnected the service battery briefly, turned the isolating switch on, and tested the voltage at the heater end of the power feed – 12.8V!! Marvellous!

I disconnected the battery again before going any further.

The next decision was to decide on a location for the thermostat. The instructions state anywhere between waist and shoulder height. At shoulder height I’d imagine the heater will take very little time to get up to temperature as heat rises, consequently it may be cooler lower down. At waist height it would take longer to get to temperature but be warmer lower down. As we spend a lot of time sat down in Dougal, we decided the best option would be to position the thermostat just above waist height, sited on the domestic switch panel and accessible from lying down in bed J.

Using an 8mm drill, 3 holes were drilled close together and then filed to form a slot to pass the plastic connector through. The control unit was then fixed to the surface using the screws provided.

The control connector halves snapped together quite easily and then the various wires were tidied up using the cable ties provided. Any excess wire from either loom was cable tied in the cupboard.

At this point I screwed the heater to the van floor, removed the electronics cover on the heater and connected first the thermostat connector, and then the power cable. If for any reason you have left the power on and connect the power first, then you risk blowing the mother board in the unit (it doesn’t mention this in the instructions but seemed to be a hot topic on various internet forums). After fitting the cable grommets and replacing the cover I used cable clips to tidy everything up in the bed box.

Step 5 – Exhausted Already

This was a case of making sure you take everything with you that you need as there is nothing as tiring as getting under your van three, four or even five times to get a screw, a clip, a screwdriver, cable ties, etc., that you forgot to take in the first place. It took me four goes and one of those was to get safety glasses to keep dirt out of my eyes (a good tip).

I also found I had a lot more room by jacking up one side of Dougal.

I used the jubilee clip supplied to fix the exhaust pipe to the heater. Before this I had decided on a route for the pipe that fulfils both the technical requirements, namely that;

  1. the pipe should run slightly downhill (to drain any condensate), and that
  2. the pipe should point anywhere from just to the rear of the heater exhaust pipe to fully pointing backwards.

The pipe preferably should exhaust towards the edge of the vehicle but as long as the two criteria are met, and it isn’t exhausting into an enclosed box section then you should be ok. Carbon Monoxide is heavier than air so will pool under the van and slowly dissipate. It’s also a good idea to make sure the exhaust is on the opposite side to the sliding door otherwise you could be exhausting into your awning and anyone sleeping in there may be hard to wake up!

The instructions also advised not to place the exhaust within 50cm of a fuel tank breather vent.

Due to the placement of my heater I couldn’t quite reach the sill of the van but it was close enough and fulfilled the technical requirements, so I was pretty happy. There was also a convenient unused cable tab for me to attach the pipe clip to.

The inlet air pipe followed a similar route, again pointing slightly to the rear of the vehicle and was long enough to reach the sill. Both pipes were specified lengths to make the heater run efficiently. Do not shorten them!

I decided to seal in the exhaust pipe with RTV High temperature sealant but left the air intake hole open to act as a gas drop vent for the bed box.

Step 6 – It’s a Gas Gas Gas!

According to the regulations (BS EN 1949), if you are going to hire your van out, you need to have the gas system fitted and tested by a Gas Safe Registered engineer (still a Corgi engineer in my head). If you aren’t hiring it out, you can have a go yourself (yikes) but it is still a good idea at some point to get it checked out by a registered engineer. On boats it is an insurance requirement to have the system certified every year, or after any change. Gas explosions and CO poisoning are the main causes of leisure boat fatalities in the UK. I suspect the risks in campervans are possibly higher as there is no legal or insurance requirement to get gas systems checked by competent people.

Food for thought, but by following simple guidelines you stand a very good chance of installing a good gastight system.

  1. Provide unique isolation for the appliance being fitted, so if there is an issue with the appliance it can be taken out of line without affecting anything else.
  2. Minimise the number of joints – if possible, use pipe bent to shape rather than compression fittings – it minimises potential leaks.
  3. Only use rubber gas hose where you need the flexibility i.e. in the gas locker. It should be as short as possibly needed. All other pipe should be treated as part of a permanent installation and be copper/steel.
  4. Flexible pipes should be replaced every 5 years (the manufactured date is on the pipe).
  5. Gas lockers, if internal, should fitted with a vent/drain.
  6. Only use PTFE tape on threaded non-compression fittings. PTFE can stop a compression fitting from being effective.
  7. Like a house, protect your pipes from damage by keeping them within the confines of the vehicle. I have seen a couple of YouTube videos where the pipes are routed underneath the vehicle and I personally think it’s asking for trouble.
  8. Happy with your installation, then test it for leaks.

It was a long time ago, but I did part of my apprenticeship as a gas pipe fitter with two Glaswegians from Corby. It’s just a shame I never understood a word they said. Anyhow I don’t have a copy of the standard and at £150 I probably won’t bother but you won’t go too far wrong if you follow the above.

My run of copper pipe to the gas locker was relatively simple – heater to small ball valve, valve to gas locker through the bottom of the water cupboard. I made a hole in the locker to house the kit-supplied rubber to copper fitting which I swapped for a bulkhead fitting to enable it to be secured on the wall of the locker. I used PTFE to put the brass elbow in the heater unit – all the other fittings were compression fittings.

4 joints in total to test, which I did by connecting the rubber hose directly to the gas bottle. I filled a large syringe (don’t ask) with 50/50 fairy liquid and water. At this point my wife came out to see if I had a drug problem she should know about, and on watching me squirt the joints with the mixture remarked “Ooh, should it be blowing bubbles like that?”.

Damn! Still a 75% success rate, and the offending joint was tightened up and retested satisfactorily.

Oh, and make sure you have kitchen roll under the joints being tested.

Step 7 – A very expensive hairdryer

It made sense at this point to test the whole system so I connected the hot air pipe to the unit with the large jubilee clip, reconnected the battery, turned the gas on, turned the “spare” switch on at the panel, and switched the controller to “flame”. I’d asked my wife to come out for the grand switch on, my kids weren’t interested, and my neighbours weren’t allowed to be there because of social distancing otherwise I’d have asked them round.

Bugger! The LED that should’ve been green was flashing red L. A quick read of the installation instructions and I discovered that due to the initial absence of gas the unit had “locked out”. One quick reset later and I tried again. Success J. By this time my wife had wandered off to feed the cats or do something more interesting. I celebrated alone but was chuffed to bits.

Step 8 – Tidying up

It’s relatively simple to install the air vents in the bed box front, once you get past the idea of drilling 2 very large 95mm holes. Once done there isn’t a lot left to do other than maybe protect the unit with a cover – so you can still use the storage space – and enjoy the heat!

Actually, one very important thing, if you haven’t installed one already, is to install a CO Alarm. If you already have one, check when you bought it as they tend to need replacing after 7 years (some may last 10 years).

Unfortunately, we can’t go anywhere as yet so we are confined to sitting in Dougal on the drive, but at least it’s warm!

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About Nick Gillott

Website Manager and General Committee member of the Owners Club. Owner of Eric the Viking (converted panel van with Viking roof) undergoing complete restoration. Tinkerer to Poppy the camper van (1972 Crossover dormobile).