Diesel or Gas heating?

[Fisherman]

Not suggesting it's a good idea, but you could have it fitted to cut off at any point. On aftermarket fitted ones, I'm pretty sure it's the length they cut the standpipe to that dictates the cut off point, both Eberspächer and Webasto recommend the stand pipe is cut off at 25mm above the bottom of the tank.

When heater is fitted by vehicle manufacturer they probably use CAN bus signal, or digital. Unlikely aftermarket instals tap into CAN bus.

Mine cuts out before the tank empties Mark. But I very much doubt if with a 75litre tank this is realistically an issue. If I pitched up with say 50 litres in the tank I could sit there for a month in winter before reaching that threshold. But I suppose better be safe.
Two things have been game changers in the new van first lithium batteries, and second the diesel heater.

 

[barryd]

Here are my ramblings on Diesel Vs Gas heating.

My older caravan had Truma gas water and space heating. They worked well, they were separate units, they operated from simple controls and did their stuff reliably and silently. Great.

My last caravan was more recent, about 2000, and had what was current then. Still Truma gas powered and separate. The water heater had more fiddly controls, but it worked okay. The gas heater was awful. The controls were most non intuitive and not explained well in the manual. It was basically a gas convector heater that could be used just as that, with an addition of the blown air kit. It was how the 2 worked together and interacted that was poor. And the basic controls for the gas heater here poorly made. And my final gripe was the ignitor for the gas fire was battery powered with really awkward to reach batteries. Why oh why not 12V powered.

Now my present demountable motorhome. That came with a gas hob, the only gas appliance in it, and a Truma diesel powered water and space heater. In true Truma fashion the manual explains the operation badly but I have got the measure of how it works now. It heats the MH and water okay once you figure out the idiosyncrasies but it is noisy. The plus point is is sips fuel very efficiently. It has a 2 gallon diesel tank and we have used less than half of that in all our trips this year. It will do weeks on a tank full and of course it is easy and cheap to re fill.

The only downside for us is the diesel tank takes up almost half of the "gas locker" meaning there is only room for one gas bottle. I refill my own bottles so we can always start a trip with a full bottle and know the hob won't empty that in one trip, but if you did not self refill you would have to carry the spare gas bottle somewhere else.

I can beat that! On our last van from the last century which I only got shot of last year it had a Carver 3000 Gas fire which had a manual plunger to light it. It was an absolute PIA. You had to get the knack just right or it wouldn't fire up. If you ended up tyring too many times a build up of gas would happen in the flue and it would explode. On more than one occasion I blew the cowl off the chimney on the roof of the van clean off and sent it into orbit.

We almost froze to death in the Alps once because of that bloody thing. When it worked though it was fantastic. Super warm.

Why do some diesel heaters though have a separate tank? It makes more sense to have it off the main tank surely. For constant heating and water I would imagine you could get through two gallons fairly quickly.

 

[mistericeman]

Yes I suppose it is a bit daft having Gas and diesel. I was more interested in how it distributes the heat. I presume they can be connected into the existing heating ducts network using all the existing heating vents and pipes around the van?

To an extent yes.... BUT duct length/bends/T's etc
Are limited before you begin to get overheat faults etc

 

[mark61]

I can beat that! On our last van from the last century which I only got shot of last year it had a Carver 3000 Gas fire which had a manual plunger to light it. It was an absolute PIA. You had to get the knack just right or it wouldn't fire up. If you ended up tyring too many times a build up of gas would happen in the flue and it would explode. On more than one occasion I blew the cowl off the chimney on the roof of the van clean off and sent it into orbit.

We almost froze to death in the Alps once because of that bloody thing. When it worked though it was fantastic. Super warm.

Why do some diesel heaters though have a separate tank? It makes more sense to have it off the main tank surely. For constant heating and water I would imagine you could get through two gallons fairly quickly.

The two main reasons would be it's a DIY job, and it's a lot easier job to take diesel from a different tank. Some vehicles may need the main tank to be dropped a bit to fit the heater pipe and then tank re fitted.
2nd, would be they have access to red diesel

 

[Geek]

My gas boiler in winter could empty a 13kg Calor in a week at a cost of £56. The diesel heater would probably use around a gallon in that time costing around £8-10.

LPGas is around 7KWh per litre (14KWh per KG) and diesel is around 10KWh per litre.
13KG of gas would be about 180KWh, which is the equivalent of 18 litres of diesel, or four gallons. That's about £25.20 worth.
Refillable LPG is about 85p per litre, so would have cost about £22.10

 

[Geek]

I would say, Diesel is cheaper than LPG, safer, saves weight, is more readily available, saves space if using cylinders, and requires virtually no maintenance.

I have LPG on the van and a CDH in my shed. I see the pros and cons of both.
LPG is cheaper, quieter, more reliable, needs less maintenance and uses less 12v power.
Diesel is l more readily available but LPG is sufficiently available in most places.

 

[barryd]

To an extent yes.... BUT duct length/bends/T's etc
Are limited before you begin to get overheat faults etc

View attachment 147686

Not sure I fully understand that but it would be essential for us in the future to have the heat pumped to where it is now especially the front of the van which is the furthest away from the current Truma right at the back and of course the bathroom. It must be doable though as I know they are on some pretty big boats.

 

[mistericeman]

Not sure I fully understand that but it would be essential for us in the future to have the heat pumped to where it is now especially the front of the van which is the furthest away from the current Truma right at the back and of course the bathroom. It must be doable though as I know they are on some pretty big boats.

Diesel heaters aren't blown air systems...

The blown air on your average truma/carver type fire.... Is just air blown over the heat exchanger in the fire....

With eberspacher types....

There is a critical balance between not being able to shift enough cabin air over the combustion chamber leading to over heat faults.
And shifting too much and leading to sooting up or burn chamber temperature too cool faults.

Thats why Eber supply max duct runs/fittings figures...
It would in theory be possible to install a booster fan....
BUT it would be a pfaff setting it up to be balanced and not constantly throw combustion errors.

I would say IF you needed long runs.... You'd be better off sticking with a truma/carver blown air.

 

[ProDave]

Why do some diesel heaters though have a separate tank? It makes more sense to have it off the main tank surely. For constant heating and water I would imagine you could get through two gallons fairly quickly.

Well in my demountable camper that would be one more thing to disconnect, a fuel line, so it makes sense to have a diesel tank built in. I only wish they had found a better location than taking up half the gas locker so I only have room for one 6Kg gas bottle.

I often carry a 2 gallon jerry can of Diesel when touring, mainly to avoid expensive fuel on the West Coast, I could hardly have that filled with red diesel for the heater could I

 

[Nabsim]

Diesel heaters aren't blown air systems...

The blown air on your average truma/carver type fire.... Is just air blown over the heat exchanger in the fire....

With eberspacher types....

There is a critical balance between not being able to shift enough cabin air over the combustion chamber leading to over heat faults.
And shifting too much and leading to sooting up or burn chamber temperature too cool faults.

Thats why Eber supply max duct runs/fittings figures...
It would in theory be possible to install a booster fan....
BUT it would be a pfaff setting it up to be balanced and not constantly throw combustion errors.

I would say IF you needed long runs.... You'd be better off sticking with a truma/carver blown air.

In regard to the last line, the other option would be to fit 2 diesel heaters, (front/back).

 

[Nabsim]

Well in my demountable camper that would be one more thing to disconnect, a fuel line, so it makes sense to have a diesel tank built in. I only wish they had found a better location than taking up half the gas locker so I only have room for one 6Kg gas bottle.

I often carry a 2 gallon jerry can of Diesel when touring, mainly to avoid expensive fuel on the West Coast, I could hardly have that filled with red diesel for the heater could I

They can mount the heater in the truck with the vents going into the camper section. Of course this then depends on the camper body not being demounted when you may want to use the heater