Technical Fitting diesel space heater into motorhome

[Bjbrownie]

I recently fitted one of those cheapo Chinese diesel space heaters to my motorhome, we do a bit of winter and autumn camping and I thought it would be a good idea to boost the heat in the van as the wife feels the cold (so do I ) the original Carver gas fire/Fanmaster blown air unit is quite good but takes about 20-30 minutes to start putting out any sort of decent heat. The diesel heater starts putting heat out after a few minutes warming up and even when set to 30 it’s bloody hot
Easy to install, hardest part is finding a suitable space to fit it bearing in mind the bulk of the heater is inside the van and you have to route wiring to the heater from the leisure battery which may be a distance away, I had to extend the earth wire. I didn’t use the 10 litre fuel tank as I was fitting it under the side panels, eBay got me a 5 litre box type one which fits nicely in and you don’t get any fumes from the small breather hole, but diesel will leak out of the top on bouncy road conditions so fit a breather pipe to the top of the filler cap (an old bleed nipple tapped into the cap an a piece of tube vented to the outside sorts that), and a few extra connectors helped join the hot air delivery pipe together neatly.
Don’t use the stupid clip connectors, use the screw ones as I found the spring ones weren’t tight enough. Also I found the control unit wire wasn’t long enough but easy to extend by soldering new wires in, I’ve heard that the diesel pump on these units is noisy but with it fitted underneath the van you can’t hear it at all. I fitted a splash guard behind the rear wheel to protect it from road splash and debris.
A worthwhile job if you use your vehicle all year round I think.

 

[chris3234]

Looks a tidy install just make sure you have a CO alarm inside your van these things can be deadly if theres a small exhaust leak into the van or even getting in around a door or window

 

[Bjbrownie]

Looks a tidy install just make sure you have a CO alarm inside your van these things can be deadly if theres a small exhaust leak into the van or even getting in around a door or window

Thanks, I have a CO detector inside and have fitted a proper seal around where the pipes/wires enter the compartment.

 

[Reg 65]

I can't see where you have fitted the diesel pump
I found that it needs to be pointing upwards by nore than the 15% suggested in the instructions - mine hangs vertically on its very short rubber hose directly below the heater, no need for mountings if you are using decent rubber hose and clips (not the stuff supplied with the kit) as it will take the weight of the pump and provide a nice flexible mounting. Otherwise cavitation will produce air bubbles and the heater will cut out and refuse to lght after a few hours use when the air bubbles have built up between the pump and heater.
Thing is diesel is hard to light - you have got to vapourise it by injecting it in high pressure spurts like in a diesel engine. Soft walled pipe (unless its very short) or air bubbles will even out the pressure, so the diesel goes in to the heater in a dribble, doesn't vapourise and doesn't burn properly.
You can use soft walled pipe between the tank and the pump, but between the pump and the heater the pipe needs to be hard walled or very short.
Good explanation here

 

[Reg 65]

I have a Fire Angel CO alarm with a panel that gives the CO content in parts per million. Depending on wind direction I can see the CO level rise when I switch the heater on as, being hot, the exhaust can rise up through vents, and drain holes in the van floor - however well you have sealed the cables and hoses going into the heater.. Since I gave up smoking my sense of smell has improved greatly and so I can sometimes smell the exhaust. But the meter shows the CO doesn't get to a level where it is a cause for concern.

 

[Bjbrownie]

I can't see where you have fitted the diesel pump
I found that it needs to be pointing upwards by nore than the 15% suggested in the instructions - mine hangs vertically on its very short rubber hose directly below the heater, no need for mountings if you are using decent rubber hose and clips (not the stuff supplied with the kit) as it will take the weight of the pump and provide a nice flexible mounting. Otherwise cavitation will produce air bubbles and the heater will cut out and refuse to lght after a few hours use when the air bubbles have built up between the pump and heater.
Thing is diesel is hard to light - you have got to vapourise it by injecting it in high pressure spurts like in a diesel engine. Soft walled pipe (unless its very short) or air bubbles will even out the pressure, so the diesel goes in to the heater in a dribble, doesn't vapourise and doesn't burn properly.
You can use soft walled pipe between the tank and the pump, but between the pump and the heater the pipe needs to be hard walled or very short.
Good explanation here

I can't see where you have fitted the diesel pump
I found that it needs to be pointing upwards by nore than the 15% suggested in the instructions - mine hangs vertically on its very short rubber hose directly below the heater, no need for mountings if you are using decent rubber hose and clips (not the stuff supplied with the kit) as it will take the weight of the pump and provide a nice flexible mounting. Otherwise cavitation will produce air bubbles and the heater will cut out and refuse to lght after a few hours use when the air bubbles have built up between the pump and heater.
Thing is diesel is hard to light - you have got to vapourise it by injecting it in high pressure spurts like in a diesel engine. Soft walled pipe (unless its very short) or air bubbles will even out the pressure, so the diesel goes in to the heater in a dribble, doesn't vapourise and doesn't burn properly.
You can use soft walled pipe between the tank and the pump, but between the pump and the heater the pipe needs to be hard walled or very short.
Good explanation here

I've fitted the pump with an angled custom bracket and metal cover just inside of the chassis so it's protected from road crap and all of the connections are kept as short as possible. Good call on the video

 

[Bjbrownie]

I have a Fire Angel CO alarm with a panel that gives the CO content in parts per million. Depending on wind direction I can see the CO level rise when I switch the heater on as, being hot, the exhaust can rise up through vents, and drain holes in the van floor - however well you have sealed the cables and hoses going into the heater.. Since I gave up smoking my sense of smell has improved greatly and so I can sometimes smell the exhaust. But the meter shows the CO doesn't get to a level where it is a cause for concern.

That's interesting-I have extended the exhaust tubing as the original piping was way too short. It's well away from the gas drop out vents and carefully checked the body for air leaks, found a few that weren't sealed up properly from the vans build, but all good

 

[Reg 65]

That sounds like how I fitted my fuel pump initially. It worked fine for a few hours until air bubbles built up - then it kept conking out.
Finally fitted the fuel pump hanging vertically below the heater on a very short piece of proper rubber fuel hose and clips (not the crap supplied) so any air bubbles produced by cavitatiuon go straight into the heater before they grow to a size where they stop it burning or knacker the pump for lack of lubrication.
Thats another thing they didn't say in the instructions. The fuel pump depends on the diesel oil flowing through it for lubrication and cooling. If the pump is running dry its like an engine running flat out with no oil and no coolant. Not only is the pump not lubricated so overheating through friction, its also lost the cooling properties of the fuel flowing through it. So if you fit a long pipe betwen the pump and the tank so the pump is running dry to pump it through, the pump may be worn out by the time the heater first lights. Cavitation air bubbles in the pump caused by it not being mounted pointing upwards enough also produce an area inside the pump that is not lubricated or cooled.
Good news is the pumps are cheap and widely available on ebay because so many people knacker them up by incorrect fitting. Even if fitted correctly from the start its a good idea to keep a spare as they work very hard. In my experience the fuel pump is the most likely cause of faults - even if it doesn't say so in the fault codes.

 

[Reg 65]

Problem is the van is stationary so, depending on wind direction, the exhaust can still be blown back underneath the van to rise up through vents and drain holes - which you need to drain out the condensation that forms on the bodyshell. So a certain amount of CO getting inside is inevitable. But there is always some pollution in the air we breath anyway. You are breathing in CO everytime you go near a road. Thats why I have a CO alarm with a meter that tells me whether it rises when I switch the heater on, and whether it remains below the acceptable level.

 

[Bjbrownie]

Problem is the van is stationary so, depending on wind direction, the exhaust can still be blown back underneath the van to rise up through vents and drain holes - which you need to drain out the condensation that forms on the bodyshell. So a certain amount of CO getting inside is inevitable. But there is always some pollution in the air we breath anyway. You are breathing in CO everytime you go near a road. Thats why I have a CO alarm with a meter that tells me whether it rises when I switch the heater on, and whether it remains below the acceptable level.

Good points there, I might look into buying one of those digital CO meters-I've seen quite a few installations on YouTube where I think the exhaust length is insufficient especially on panel van conversions where space is at a premium and the exhaust runs close to door seals

 

[Reg 65]

well I have added an extension (using copper plumbing pipe) so the heater exhaust comes out the side of the van as far as the vehicle exhaust.
But the wind still blows the exhaust fumes back undereath if the van is stationary and the wind is blowing that way. Then rises up into the van as hot air rises. I can't block up all the vents and drain holes under the van so I can't see a way round this - other than to monitor the CO inside the van with my digital CO meter to check the level is acceptable.

 

[chris3234]

well I have added an extension (using copper plumbing pipe) so the heater exhaust comes out the side of the van as far as the vehicle exhaust.
But the wind still blows the exhaust fumes back undereath if the van is stationary and the wind is blowing that way. Then rises up into the van as hot air rises. I can't block up all the vents and drain holes under the van so I can't see a way round this - other than to monitor the CO inside the van with my digital CO meter to check the level is acceptable.

What about shield around the vent e.g like a tube around it with the bottom closed off but the side open a
So the fumes would have th blow back the forward a little again to go up and inside the tube

 

[Reg 65]

I see what you mean, but the problem is its not just one - there is a lot of vents and drain holes that ultimately lead up into the box sections and into the van with the hot exhaust gas rising up
Be a job and a half to try and shield them all.
So far its only been a max of 10ppm and only when the wind is blowing the exhaust back under the van, so I can live with that.
We can't escape pollution altogether.
I wouldn't have known about it if the alarm didn't have a meter because it isn't enough to set the alarm off.

 

[Bjbrownie]

To be honest I wouldn’t worry too much, this type of heater is used extensively on ambulance type vehicles and run constantly in the winter months so I don’t really think there’s too much cause for concern provided the exhaust points away from the vehicle. The floor of my van is about 3ft from the ground so I think any fumes directed downward would disperse. Just a thought.

 

[Reg 65]

I have a Fire Angel CO-9D alarm which I am happy with
The CO meter is good for checking fumes from the gas stove as well as the heater.
The battery is not replaceable - but I think thats an advantage for 2 reasons
1) by the time the battery wears out the sensor will need replacing as well
2) The battery has permanent connections which avoids the problem of corroded contacts
You can turn it off to conserve it by re-inserting the bit of bent wire that comes with it