Installing a heater

carrier82

Petty Officer 2nd Class
Joined
Oct 1, 2013
Messages
118
Hi

I was planning to install a water separating fuel filter (boat doesn't have one yet) that has multiple output connections with my heater retrofit. I have a Carter electric fuel pump on my engine (350) and I'm guessing the heater's own fuel pump can't draw fuel through the engine fuel pump when engine is not running. It if could, it would be simple to install the fuel filter after the fuel pump and feed both the engine and the heater from the filter. The heater is an Ebersp?cher bn4 gas fired, recently refurbished heater. Before you tell me I can't install a gas heater on the boat, it is allowed where I live on boats of this age. Of course I have to be absolutely certain the fittings are done properly.

So my question is: Installing the fuel filter before the Carter fuel pump would probably lead to trouble as the pump would have to draw excess air through the filter and I guess that's beyond the fuel pump's abilities. Can I permanently install a hand pump similar to the ones used in outboards before the fuel filter to fill the system after a filter change?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Avoid all the potential issues by installing check valves in the engine and heater supply lines. Just because you run the heater and engine from the fuel filter doesn't automatically prevent back flow of fuel from either the heater or engine line. If you do that, it would probably be necessary to remove the anti-siphon valve at the tank. The anti-siphon valve you add to each line would take care of the siphoning issue.
 

alldodge

Moderator
Staff member
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Mar 8, 2009
Messages
40,582
So my question is: Installing the fuel filter before the Carter fuel pump would probably lead to trouble as the pump would have to draw excess air through the filter and I guess that's beyond the fuel pump's abilities. Can I permanently install a hand pump similar to the ones used in outboards before the fuel filter to fill the system after a filter change?

All fuel pumps both mechanical and electrical have the ability to draw fuel through the filter. All filters are installed by the manufacture before the pump, this is to protect it. Main issue with installation is keep the filter at the same level as the tank. Increasing the height above the tank also increases the amount the pump will work to pull fuel up. Check to make sure your anti-siphon valve is in good working order to keep additional restrictions down
 

carrier82

Petty Officer 2nd Class
Joined
Oct 1, 2013
Messages
118
Thanks for the tips. I?ll install the filter before the engine fuel pump. After reading the heater installation instructions, it occured to me that the heater?s own fuel pump isn?t powerful enough for my application and I?ll have to install an auxilliary pump as well. Any suggestions for a cheap electric fuel pump for low consumption applications with adjustable fuel pressure?
 

carrier82

Petty Officer 2nd Class
Joined
Oct 1, 2013
Messages
118
Got a cheap HEP-02A fuel pump off ebay. According to my calculations based on maximum fuel level (rated) height of the heater pump (hydrostatic pressure) the input pressure to the heater pump should not exceed 0.5 psi. I might calculate the pressure loss to determine if I need a pressure regulator as well.
 
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