Gas Installation Part 3. Regulator and Connections

With the gas tank finally hung under the driver side chassis, and the fill point fitted to the column behind the drivers door, the next job was to connect everything up.

Here’s the layout:

Connecting up the gas appliances, (not showing the inlet and outlet for the propex heater)

We originally bought a filter that is supposed to go between the gas tank and the regulator. It screws directly to the tank ‘out’ valve in the air box on the LPG tank. The idea is that it catches oil/ water vapour/ crud in the tank? (Gasit were extremely vague about this) and when I finally called them because I couldn’t actually fit this filter to the tank because of the exit points from the air box are so tight around it that I wouldn’t be able to tighten the joints, plus there was no way of supporting it and it’s quite heavy so would jiggle around a LOT he implied that it was a bit unnecessary anyway so I sent it back.

Fill point to tank

Connecting the fill point to the tank was straight forwards. This is a steel braid coated pigtail with female ends.

Tank to regulator

The tank outlet is connected to the regulator which is bolted to the bottom of the van floor. This is also via steel braided pigtail.

Regulator to manifold

From the 8mm compression fitting of the regulator,  a PVC coated copper pipe (8mm) is run through a hole in the floor to a manifold which is supposed to be in an accessible place inside the van. Each appliance can be isolated here if there are any problems. We got a 3-way manifold  (about £22 from Rainbow conversions) in case we get a water heater in the future. For now the third outlet is blanked off.

Here is an ‘under the van picture’

Underneath the drivers side of the vann

Drop out valves

There also needs to be a drop-out valve (gas is heavier than air so it sinks down and out of the hole in the floor) in case of a leak. We put one in the cupboard where the heater and hob are, and another where the manifold is.

The hole I drilled for the drop out valves wasn’t quite big enough and the two parts of the valve don’t fit together all the way through the floor so it sticks out at the bottom. I sealed around these holes and the hole for the copper pipe with silicone.

The hob

This is from Dometic. It has 2 burners and a glass lid. We have now used this for a couple of months.


  • Seems to work well.
  • The big burner is enough to get a 24cm frying pan really hot.
  • The small burner turns low enough for a gentle simmer.
  • The pot supports are sturdy, and can be removed for cleaning (although one little rubber bungs that holds the feet of the pot support in has already come out and so doesn’t  support the pot stand fully. And would leak if there was an over boiling pot).
  • It was relatively easy to fit although it didn’t come with a template for cutting the hole in the work surface.
  • When the lid is down, it provides extra worktop space.


  • The glass lid feels horrible and is noisy- I would like to replace it with a nicer material.
  • It is really fiddly to clean and the knobs are tucked away in a dip which collects crud and grease.

Propex heater

This is the 2000 HS model with 1 outlet for heated air.

It comes with a handy template because you have to drill holes in the floor of the van. One hole for the air inlet  to the combustion chamber and another for the flue for the combustion products. This means that unlike a lot of gas heaters (or using your gas hob to heat the van), the water produced by burning the gas ends up outside so reducing condensation.

Air from inside your van is taken in to the heater by vents in the cupboard that you put the heater in and is circulated by a fan over the heater and then blown out back into your living space via a big cardboard tube via another vent (swivelling) in your cupboard. These vents and this process is completely separate from the combustion part of the heater

The heater itself is also screwed to the floor.

Here is a picture of our heater before we built the cupboard around it.

Propex heater with air inlet and hot air outlet taped up (temporarily)

It also needs a power source and then the thermostat and control knob are connected via a fairly long cable so you have a bit of flexibility where you can mount the thermostat.

So all in all the heater is a palaver to fit- you need to consider many things:

  1. The position of the cupboard or floor space it is in because of the vents through the floor and where they emerge under the chassis.
  2. The passage of the gas pipe (8mm) from the manifold.
  3. The power cables from the fuse box cannot be too long (to avoid a voltage drop)
  4. The position of the thermostat and the cable that runs to it. (Please Propex, make a wireless model)
  5. Lastly, the air intake via vents in the cupboard must be accessible and not easily blocked by furniture or clothing etc and the same goes for the air outlet vents. In our case we had practically no space for the cardboard tube before it reached the vent so it is only about 10cm long.

We’ve used it for a couple of trips now, and while I would not be without a heater, there are a few things we don’t like about this one.


  • It seems to be reliable (so far we’ve used it for a couple of months).
  • It seems to be sturdy and well made.
  • The Propex engineers are extremely helpful and friendly.
  • The fitting instructions are good and clear.
  • The cables and tubes are reasonably generous.
  • You can direct where the hot air goes by swivelling the vent.


  • It is pretty noisy – much louder than we expected – like a domestic fan heater or a bathroom extractor, but it’s in a much smaller space.
  • The fan runs for about 20 seconds before the heater kicks in and for a minute or so after it has switched off.
  • The thermostat seems somewhat insensitive. We have only heated the van up once enough to trigger the thermostat to switch off, and because its so loud we would rather control when it kicks in ourselves, so generally it is switched off until we need it.
  • The thermostat is a big ugly plastic box with horrible ugly knobs.

2017-12-14: Gas installation part 2

So this post was drafted as we nearly came to the end of fitting the gas tank and bits and pieces. We were waiting on an inspection by a gas safe engineer who pressure tested the system with a small amount of gas before we filled it with gas. Of course there was always the possibility that he would take one peek at the set up and condemn it before we even got to the test. As it was, he made a few small changes and also discovered that the whole set up was somewhat leaky and the engineer pretty much redid all the joints. He also pointed out that for about the same price as we had paid for everything in the end, they could have installed an almost identical setup and saved us all the pain. (For the record, that is the Propex engineers in Southampton).

Part 1 finished with us waiting for some special brackets to be made because our Sprinter is apparently unusual in that it is missing an essential bit of steel that the gas tank should have bolted on to. We had an 81cm gap instead of a 55cm gap.

Anyway, at a cost of another £45 two steel angle irons were cut to length, had one side of the angle shaved from 5cm to 4cm and then had holes drilled at appropriate points (twice because I got my mm and cm mixed up and the first lot of holes were 60mm apart, not 60cm)

Then we used the original brackets from  Gasit and bolted these to the outriggers under the van.

Brackets from Gasit bolted to the outriggers as per their suggestion.

As you can see, we had another worry. This time that the exhaust would be venting onto the tank and it’s fittings, and the heat would make us into an IED. So we tried to fashion a  heat shield from sheets of galvanised steel that we got from Wickes ( actually sold as protective door plates I think) which we screwed directly to the main chassis beam that runs the length of the van.

The next job was to fit the angle irons to the red brackets followed by the feet of the gas tank to the angle irons. The problem was that the bolts attaching the angle iron to the bracket and tank closest to the heat shield would no longer be accessible after the second angle iron was in place so we had to fit the tank and one angle iron first, and then somehow squeeze in the second angle iron and the next set of bolts, all in a very awkward space, with the tank supported on a car jack and some paint pots and in sub zero temperatures

The first angle iron is in

You can see that even though we set the tank as close to the main chassis beam as we could, there was still barely enough room to manoeuvre and also very little space to access the airbox (where the tank in and out valves are housed)

You can also see that the underbody seal stuff just rubs off the tank. It stayed pretty sticky for about 2 weeks after spraying it on which made the whole job even more unpleasant. It’s like tar.

Once the tank was secured we drilled the hole for the fill point in the pillar behind the driver door. This is hollow and has a handy rubbery bung underneath to allow access into the pillar.

Hole drilled for the fill point behind the drivers door.

I had ordered an angled fill point, but a straight one probably would have been better.

View looking up into the hollow pillar at the fitted fillpoint.

We fitted a 75cm angled fill hose to this fillpoint and fed it through a hole drilled through the side of the pillar which you can just see in this picture. I was worried that the hose would chafe so glued in a bit a plastic drainpipe to this hole to guide the fill pipe round the corner. 75cm was only just long enough. A longer fill pipe would have been better here, but this bit was a breeze compared to fitting the tank.

The fillpoint looks fine from the outside too

Fitted fillpoint

As it turns out, You are not supposed to fit these things in this orientation. The gas safe man ended up turning it around 90 degrees so that the cap ends up horizontal.

Part 3 will detail fitting the regulator and propex heater.


2017-07-09: Fitting roof light and fan

We fitted the fan and the roof light this weekend. Each job took a whole afternoon.

I started with with the Maxxfan. I didn’t take many photos because the whole job was a bit stressy and I wasn’t sure it was going to work. I needed to concentrate.

The Maxxfan is great – we were pleased with it straight out of the box. The plastic is not flimsy, installation is well thought out and it looks good. It is designed so that you can fix a retaining ‘flange’ to the roof and then the machine itself screws onto the flange later. This means you can easily remove the machine for repair without having to phaff about with the bit that holds it onto the roof. Likewise, the decorative bit inside that hides wires etc gets screwed in place independently.

This is a bonus for us because we don’t yet know what we are going to clad the van with, and how thick the roof will be. So we can still drive about with the fan fixed in and worry about trim later.

Caravan bits are designed for flat roofs. The sprinter doesn’t have a flat roof in any direction – it has bobbly bits which can’t be avoided.

I started by trying to draw the 40cm square  for both the roof light and the fan on the ceiling of the van where we wanted the holes to be.

This was very difficult, (rulers too long/ short/ bendy, neck and arms hurting, right angles never matched up).

marking the roof light square inside the van

I got fed up in the end and using a punch, made some discrete mini dents (one at each corner) then got up on the roof and using the dents as a guide measured the 40cm square again (much easier on the roof).

Here’s the square for the fan:

The square marked out for the fan (close to the back of the van)


And here is square for the roof light

The 40cm square for the roof light, near the front of the van

Then I cut out some squares of some plastic stuff we had hanging about at home that we found on a skip. (Andrew know what it’s actually called – Andrew: it’s called expanded PVC). it’s bendy, about 6mm thick and can be carved easily with a Stanley knife. The squares matched the flange for the roof light  (variable widths) and the fan  (same width all the way around) and also had a 40cm square hole cut in the middle.

The plastic insert for the roof light

Next I carved bits out of the plastic insert to correspond to the bumps on the roof. Each cut is at about a 45 degree angle or more to accommodate the roof shape at best as possible.

Then I sanded the plastic and cleaned it with degreaser.

The following photos and account are mainly the roof light, but I’ve slipped in a couple of photos from the fan where I didn’t have the equivalent roof light photo.

We were pretty disappointed with the roof light when it arrived. It was advertised as white but is in fact more magnolia coloured. It feels flimsy, and the installation needs you to have determined the thickness of your roof.

The roof light. (No forced ventilation so it doesn’t whistle when we drive)

I sellotaped a bin liner inside the van to catch the worst of the metal filings, and a bit of cardboard on the roof to try and stop them getting under the solar panels.

The bin liner sellotaped inside the van to catch metal filings (fan)

Then the noisy bit!

Up on the roof again, I drilled a hole in each corner  (10mm bit) for the jigsaw bit to start in. Then I cut the four lines.

To minimise vibration I put duck tape across each cut I had made when I finished that side of the square. It also stopped the cut out falling into the van.

I didn’t bother with masking tape on the plate of the jigsaw because everything is going to be covered with sealant. We have a cheap  £40 jigsaw from Machine Mart and it did the job fine. Going over the bumps was noisy, wobbly and a bit tricky, but I found if I kept the front of the base plate pressed down where possible while keeping it level, it didn’t matter too much that the back end was in the air and the blade coped ok.

Hole cut for the roof light

The bit of cardboard didn’t work – the filings got everywhere. So after filing down the edges I hoovered the whole roof and everywhere else and removed the bin liner carefully.

I sanded the edges and a little way around the opening, cleaned with degreaser,  painted Hammerite primer on the bare metal edges and had a cup of tea.

Then I stuck butyl tape (see in the picture above) around the opening to seal the plastic insert to the roof.

Butyl tape stuck around the hole for the roof light

The tape was 20mm wide so in some places I used two strips. You can cut it with a Stanley knife. It’s like chewing gum.

Then I put the plastic insert on the top of the tape:

My plastic insert on top of the butyl tape.

I used Sikaflex Caravan Sealant 512 (also pictured in earlier photo) to seal all the way round and fill any gaps between the insert and the bumps on the roof.

This sealant sets (stops being sticky) but stays rubbery. I think the butyl tape doesn’t set (the bag it came in was not airtight at all). Ordinary bathroom silicone sealant which I intended to use originally dissolves the butyl tape and turns it into a slimy mess (lucky I tested it first).

Now the insert was in place I wanted to get everything tightened up together before the sealant set.

In the case of the fan, I put a continuous square of butyl tape on top of the plastic insert and the provided roof insert is then screwed (using about 20 screws) through the metal of the van roof. We also cut four bars of wood and clamped them inside the van so that the screws went into wood after they had gone through the roof (the sandwich of materials went like this from top to bottom: maxxfan plastic roof insert, butyl tape, my homemade plastic insert, butyl tape, roof metal, wood) Then I sealed all around the edges and over the screw heads in a big smeary mess.

The fan in place and fixed to the plastic flange insert that has been screwed to the roof  – you can just see the screws.

The bits of wood that we used inside the van were a last minute decision when we realised how the screws just poked randomly through the roof.  They aren’t totally necessary. In retrospect it would be better to make something neater and smaller in advance (like we did for the roof light).

In this picture the fan has already been lowered into the plastic fixing flange in the roof hole.

The roof light was slightly different. Since repairing or replacing the roof light involves removing the entire thing- the seal needs to be less permanent.

I applied a thick bead of Sika Lastomer 710 as per instructions to the underside of the roof light. and eased it into the hole. This stuff stays flexible and sticky, like the butyl tape.

This picture shows the underside:

Underside of roof light

It is supposed to have a clearance of 2-3mm all the way round. (my hole was a titchy bit tight but its almost impossible to re-jigsaw a cut and filing more than 1mm off a cut edge isn’t feasible either, so i’ll just have to hope its OK).

I used about half the tube of Sikaflex and it bulged out nicely from under the plastic so I know I got a good seal, but it was a bit messy clearing the excess away.

Roof light sealed into place

Off the roof and into the van now.

Here is the bit that fits inside the van:

Roof light plastic insert fits inside the van.

Andrew had earlier made a 40cm square out of 12mm plywood, 50mm deep and held together with small metal brackets at the corners: you can see it in the video at the end but I forgot to photograph it.

This filled the gap inside the van between the bit of the roof light that sticks through the hole you’ve cut and the bit of plastic inside the van (way more complicated and fiddly than the maxxfan). You are supposed to measure the gap between the inside of the roof and the cladding of your van to calculate how much to chop off the plastic bit inside the van.

We haven’t insulated or cladded the van yet so we had no idea about this. The maximum depth the plastic can extend to without leaving a gap is 60mm anyway and since our celotex insulation is 50mm, Andrew thought the wooden frame should be 50mm deep. Turns out that this was a perfect guess.

The plastic bit that fits inside the van and is supposed to slot inside the plastic square poking down through the hole. The screws marry up and their plastic surrounds butt up against each other. This is what braces the inside part and outside part and holds the roof light in place.

Yep- we thought it was all rather flimsy too. So the wooden frame is to prevent too much compression.

Roof light stuck onto roof and inner plastic flange screwed into place from inside the van to pull it down onto the roof and tighten the seal. Wooden frame sandwiched between the two parts.

Later you clip the rather hideous peachy plastic trim to the plastic bit I’ve just screwed into place. Won’t be doing that till we’ve cladded the van inside.

Decorative trim that goes inside. Nasty mottled beige blackout blind and a useful fly screen.

Next I went back onto the roof and attempted to clear up the bulgy bits of sealant. Not very successfully – it looked rather a mess.

This bit wasn’t too bad. You can just see the plastic insert I made.
This was the worst bit – where I tried to clear excess Sika Lastomer, I disturbed the not quite set Sikaflex sealant I had applied around my plastic insert

Here are the tools I needed for the job.

Ladder, Towel, Jigsaw with metal blade, Drill and 10mm drill bit for metal,  extension cable, hoover, ear muffs, googles, Hammerite paint and small brush, metal file, Sharpie, ruler, set square, tape measure, pencil, punch and hammer, duck tape, masking tape, large bin liner, paper towel, degreaser (strong detergent), sandpaper, butyl tape (20mm X  9 metres was plenty) SikaLastomer 710, Sika Caraven sealant 512, caulking gun, screw drivers, a few bits of wood and angle brackets and a couple of large clamps, a sheet of 6mm plastic, Stanley knife.

Tools for cutting the hole in the roof

Here is the Plastic insert I made, Sikaflex caravan sealant 512, Sika Lastomer 710,

The plastic insert I made, Sikaflex, SikaLastomer and butyl tape.

Here’s the video: