Fuel supply to a diesel heater

[sequena1]

As part of a rebuild I'm putting in a new main diesel tank and piping. As I'm contemplating installing a diesel heater I'd like to know whether I can tap a spur into the main engine supply pipe (possibly from the second "out" connection of the filter), or should the heater supply be kept entirely separate? Thanks for your thoughts in advance.

 

[EUXINE_Rival]

I fitted an eberspacher two years ago and it was easy enough to drill the tank and put in a seperate fuel line. Saves any problems wih lack of fuel to engine or heater. There was a good article in one of the magazines on fitting a heater, well worth looking for it.

 

[jeremyshaw]

Mine is tapped, like you suggest, after the filter. Have not used it much so can't say it is the right way, but is was the factory way and I see no problems with it. You'd definitely want it filtered and it would be a pain to install another filter unit just for that.

 

[savageseadog]

Put it on the filter but would suggest putting a stop cock in line for maintenance

 

[Csail]

I would / have keep it totally seperate. get a fuel pump from a scrappy to top up a seperate tank from the main.

 

[fireball]

We've just put a small oil can in a convenient place and tapped a fuel line into it - no connection to the main tank at all ... cost ... a couple of quid for the connectors and fuel line...

 

[ms1]

I think normal wisdom is that you supply the heater from your main tank. However under the new diesel taxation arrangements we are expecting NOV 2008 if you had a separate tank for your heater you would be legally permitted to fill it with red diesel. If you have boat safety scheme considerations I suspect you will find that all tanks have to be fillable from outside the boat.

 

[fireball]

Whats wisdom got to do with it? Why is it wise to feed a heater from the same tank as your main engine? Convenience I'll go with ...

Oh - as for filling my tank outside the boat - that's easy ... just unscrew the top and lift the whole thing out ... take it home if you've got a spare cap ... /forums/images/graemlins/grin.gif

 

[Gunfleet]

If you look at the BSS booklet that rule is for tanks over 6 gallons, which have to spill over the side when they spill. Being able to feed the heater from a separate tank may be a distinct advantage soon!

 

[fireball]

hmm 6 gallons ... na - we're on ~ 2 litres!! - Stop gap measure till we decide what to do ... although it works quite nicely as it is ...

 

[pbeard]

If you do tap your main tank ensure the feed pipe to your heater only goes down to no closer than 2 to 3" from the bottom to make sure you aren't able to leave the heater on and empty your tank, because that will be when you will need your engine!

 

[Robin2]

If you share a feed-line from the tank there is a risk that either the engine or the heater will draw air from the other rather than drawing fuel from the tank.

The eberspacher fuel connection is a narrow metal tube that goes down into the tank from the top. Obviously the eberspacher version has a flange and screw fitting to fix it to the tank.

However I got mine working for a long temporary period using a bit of brass tubing that I got from B&Q. I used about 50mm of fuel hose for an engine (from a motor-factors) to join the brass tube to the flexible feed hose for the heater. If you go this route get a very narrow metal pipe so that the heater's fuel pum does not have to draw up much fuel when it is priming.

By the way one could easily solder a brass flange around the brass pipe to make a more permanent fitting - B&Q also do brass sheet (I think), or you could use a brass washer.

 

[savageseadog]

[ QUOTE ]
If you share a feed-line from the tank there is a risk that either the engine or the heater will draw air from the other rather than drawing fuel from the tank. It might be worth putting one on the engine outlet as well if you think you'll be running the heater while maintaing the engine. It's worth using the main fuel filter to avoid duplication. If you run the heater on raw fuel from the tank it will clog up.



[/ QUOTE ]I'm sorry but this is oft repeated nonsense. The eberspacher pump is by default non return. How exactly is air going to get into the fuel supply from the engine's injection system? If you've got air in the fuel system the engine won't run.
I do suggest fitting a stop cock on the outlet to the heater for maintenance.

 

[Robin2]

I don't mind if you say I talk nonsense, but I do object to being mis-quoted.

 

[savageseadog]

Looks like my post went wrong somewhere /forums/images/graemlins/smile.gif

 

[Gumpy]

It doesnt quite happen that way, my Mikuni and Old Dutch are fed from the same line and fuel filter. If the fuel filter in my heating line is clogged then when the mikuni fires up it puts the diesel stove out which is gravity fed by sucking all the available diesel away from the stove.

Always reminds me to change the filter though.........

Julian

 

[ms1]

sequena
so the answer to your question is YES you can tap into the main fuel tank.