Diesel Heater Fuel Pumps

[Fire99]

Hi all,

The trusty ol diesel heater seems to be getting lots of conversation at the mo so I thought I'd throw a quick question out there...:

Fuel pumps.. I have a couple of Chinese and one Eberspacher diesel heaters and all the instructions require the fuel pump around the 30-45 degree angle.
Now I'm a member (ok a member of one less now) of a few Chinese diesel heater groups and somehow I upset the US/Canada Lavaner sales guy (the moderator of one group) by suggesting to someone struggling with poor heat output, to check the fuel pump angle is around the 30 degrees mark (and check the advanced settings haven't got unusual hz / fan speed settings)..

That prompted a pretty rude response from Mr Lavaner USA (This isn't the Chinese Director who seems ok, but that's one brand I won't be using in future) saying I was literally spouting nonsense and eventually disclosing the reason for his bizarre rudeness was that 90 degrees (vertical) is fine.
Now my issue with 'captain Lavaner' is his attitude (just saying I was spouting nonsense without any form of 'why', and when I said my instructions said 30 degrees he basically said I was lying, until I showed a screenshot), but for me it does seem to be a point of contention. I see a camper van fitter here in the UK says vertical is completely fine, so I'm not arguing against it but logic would suggest that if vertical was ideal, surely all the heater manufacturers would simply say to fit the pump vertically?? It's a lot simpler for the installer to fit a vertical pump rather than wiggling the pump around aiming for 30 ish degrees (give or take).
I get that it's a very simple piston pump and it's about dealing with the air bubbles but can anyone here with a better physics knowledge than me suggest why 30 and is 90 really just as good?

Like a little soap opera in a thread
cheers,

Nick

 

[vyv_cox]

Planar installation instructions only say 'a slight angle upwards'. I am currently editing instructions for another heater, which quotes 15 - 35 degrees and warns against vertical mounting but gives no reason.

 

[Beneteau381]

Hi all,

The trusty ol diesel heater seems to be getting lots of conversation at the mo so I thought I'd throw a quick question out there...:

Fuel pumps.. I have a couple of Chinese and one Eberspacher diesel heaters and all the instructions require the fuel pump around the 30-45 degree angle.
Now I'm a member (ok a member of one less now) of a few Chinese diesel heater groups and somehow I upset the US/Canada Lavaner sales guy (the moderator of one group) by suggesting to someone struggling with poor heat output, to check the fuel pump angle is around the 30 degrees mark (and check the advanced settings haven't got unusual hz / fan speed settings)..

That prompted a pretty rude response from Mr Lavaner USA (This isn't the Chinese Director who seems ok, but that's one brand I won't be using in future) saying I was literally spouting nonsense and eventually disclosing the reason for his bizarre rudeness was that 90 degrees (vertical) is fine.
Now my issue with 'captain Lavaner' is his attitude (just saying I was spouting nonsense without any form of 'why', and when I said my instructions said 30 degrees he basically said I was lying, until I showed a screenshot), but for me it does seem to be a point of contention. I see a camper van fitter here in the UK says vertical is completely fine, so I'm not arguing against it but logic would suggest that if vertical was ideal, surely all the heater manufacturers would simply say to fit the pump vertically?? It's a lot simpler for the installer to fit a vertical pump rather than wiggling the pump around aiming for 30 ish degrees (give or take).
I get that it's a very simple piston pump and it's about dealing with the air bubbles but can anyone here with a better physics knowledge than me suggest why 30 and is 90 really just as good?

Like a little soap opera in a thread
cheers,

Nick

Link to the group? Perhaps a few wise members could add input? ?

 

[Fire99]

Planar installation instructions only say 'a slight angle upwards'. I am currently editing instructions for another heater, which quotes 15 - 35 degrees and warns against vertical mounting but gives no reason.

Interesting, thanks for that.. There does seem different trains of thought but on the Chinese front, Triclicks and Maxspeedingrods (perhaps the most ridiculous name ever) in the UK seem to either be 30 or 15-30 ish degrees. The Lavaner guy went a bit ballistic that apparently a particular manual categorically says 90 degrees is fine..

 

[Fire99]

Link to the group? Perhaps a few wise members could add input? ?

I would if I could but I was unceremoniously ejected from the group for suggesting an apology may be in order and I can't remember the group name as I think I'm blocked. My first online blocking. . Oh the shame

 

[vyv_cox]

Interesting, thanks for that.. There does seem different trains of thought but on the Chinese front, Triclicks and Maxspeedingrods (perhaps the most ridiculous name ever) in the UK seem to either be 30 or 15-30 ish degrees. The Lavaner guy went a bit ballistic that apparently a particular manual categorically says 90 degrees is fine..

The Planar quote is from the text. The diagrams show two types of pump, one 5 degrees, the other 10 - 20 degrees.

 

[Fire99]

The Planar quote is from the text. The diagrams show two types of pump, one 5 degrees, the other 10 - 20 degrees.

Thanks, 5 degrees must be pretty tight to calculate and maintain but not too many degrees above the horizontal seems the most common across the board.

 

[graham]

Personally I think it should be decided with pistols at dawn.

 

[Fire99]

Personally I think it should be decided with pistols at dawn.

Surely it's the only gentlemanly way of dealing with these things

 

[lustyd]

Mine is vertical and until recently was the original 20 year old pump on the Eber installation which was a pro install.
I can see that it might use a bit less electricity if it’s flatter, but aside from that it clearly works just fine. I did consider mounting the new one less vertically but just seemed a lot of work for no apparent benefit. Really would like to know the reasoning behind the recommendation.

 

[Fire99]

Mine is vertical and until recently was the original 20 year old pump on the Eber installation which was a pro install.
I can see that it might use a bit less electricity if it’s flatter, but aside from that it clearly works just fine. I did consider mounting the new one less vertically but just seemed a lot of work for no apparent benefit. Really would like to know the reasoning behind the recommendation.

Interesting isn't it? I accidentally fitted mine vertically for a while and it didn't seem to complain but when I read the various instructions they seemed to want a fairly shallow angle.. It's a bit of a mystery to me.

 

[spudnukem]

From what I know(!?) The pumps are only lubricated by the fuel. If it drys slightly it can wear pretty quickly. Read it somewhere but don't remember where!

 

[Fire99]

From what I know(!?) The pumps are only lubricated by the fuel. If it drys slightly it can wear pretty quickly. Read it somewhere but don't remember where!

I heard that in a few places too. It's a simple piston just lubricated by the fuel, hence the concerns of some Kerosene not having enough lubricating 'ingredients'. I'll have to have a little ponder on the physics and see if I can come up with an idea.. Or not.

 

[thalassa]

A dealer in Autotherm Planars told me that they work in any position, but if placed horizontally they do not close fully as they might not fallback into the seat after they had been pulsed by the ECU. Especially after some years of use. The fuel in the tubing then might siphon off to the tank. Hence the incline. In vertical position, they would be more vulnerable to wear.

 

[oldgit]

Personally I think it should be decided with pistols at dawn.

pumps ?

 

[lustyd]

In vertical position, they would be more vulnerable to wear.

But without an explanation as to why this makes no sense to me. Vertically they stand a better chance of keeping fuel in, as any child with a glass of water and some paper will tell you! Vertical will also give more consistent pressure on parts, thus preventing wear on one side which would happen faster.

Anecdotally, if my old pump lasted from 1999 until 2023 in a vertical orientation I'd say wear isn't an issue. Even at Eberspacher prices that's only £6 a year and the generic one would be £1 a year which for a consumable part doesn't seem crazy. It was actually still working when I replaced it, just occasionally needed a tap to get going.

 

[Fire99]

A dealer in Autotherm Planars told me that they work in any position, but if placed horizontally they do not close fully as they might not fallback into the seat after they had been pulsed by the ECU. Especially after some years of use. The fuel in the tubing then might siphon off to the tank. Hence the incline. In vertical position, they would be more vulnerable to wear.

Gotcha.. That sounds the most logical explanation.. I did hear somewhere about wear in the vertical position but I couldn't say why that happens other than perhaps (and this is firing from the hip) gravity removing residual fuel from the piston surround between strokes. Something like that perhaps.

 

[lustyd]

surface tension should stop that in the vertical position though, it would be more of an issue at an angle. Not that it matters anyway since there's no air to replace the fuel so actually all that would happen would be new fuel sucked down from above. The pressure here would be due to the height of the heater above fuel tank anyway so I can't imagine the pump would play a part in that at any angle.

 

[Graham_Wright]

Vertical but which way up?

 

[vyv_cox]

I asked Owen (tech director of Autoterm) He says all the branded heaters use the slope of around 15-30 degrees except a special Webasto one. The slope ensures no air and is quieter. The horizontal info from a dealer is incorrect as there is a spring return. Important that the hose continues to run uphill to the heater.