Diesel filter connections

[jtylr]

Please can someone help with the following:

 

I have a CAV filter with what I think is a ‘spare’ inlet/outlet which is currently fed by a day tank.

 

I am planning to install a diesel heater dropped down into the swim (currently in the middle of prepping for paint) - can I just connect the fuel line to the no.1 outlet and utilise the same filter to save me tapping the tank?

[Alan de Enfield]

You could, but it would not be the norm.

 

Normally the 'dip-pipe' for the engine will go almost to the bottom of the fuel tank (just sit above the muck and water level) and any other appliance using fuel would have a shorter 'dip-pipe' so that the appliance will stop running before you don't have enough fuel left to run the engine.

 

If you connect it as proposed, you could use all the diesel sat running the heater and have none to start / run the engine.

Edited June 21, 2022 by Alan de Enfield

[Tony Brooks]

And there is a possibility the engine might eventually suck air back through the heater.

[Tonka]

14 minutes ago, jtylr said:

Please can someone help with the following:

 

I have a CAV filter with what I think is a ‘spare’ inlet/outlet which is currently fed by a day tank.

 

I am planning to install a diesel heater dropped down into the swim (currently in the middle of prepping for paint) - can I just connect the fuel line to the no.1 outlet and utilise the same filter to save me tapping the tank?

Where is the engine lift pump. If like mine it is before the filter, how would your heater work when the engine is switched off

[Tony Brooks]

15 minutes ago, Tonka said:

Where is the engine lift pump. If like mine it is before the filter, how would your heater work when the engine is switched off

 

It looks like a primary filter (agglomerator) to me and if so it is on the day tank side of the lift pump (assuming the engine is not gravity fed).  Actually without a front view that might be a water trap (sedimentor) and those leave about 20% of the muck and  water as small particles in the fuel. Maybe the OP should post another view.

[jtylr]

Thanks for the replies.

 

@Alan de Enfield My day tank should be called a half day tank really, as it holds about 4l. I am used to topping up before starting a journey. Dip pipe is right at the bottom.

 

@Tonka I am fairly dense when it comes to engines, I assume the lift pump is where the pipe/hose are leading to from the filter?

 

I will attach a photo of the whole system shortly - I can’t resize it to under the attachment limit on my phone 

[Tony Brooks]

7 minutes ago, jtylr said:

I will attach a photo of the whole system shortly - I can’t resize it to under the attachment limit on my phone 

 

If you want us to confirm what that "filter" actually is we need a front view that shows whatever forms the body of the device.

[Tonka]

7 minutes ago, jtylr said:

Thanks for the replies.

 

@Alan de Enfield My day tank should be called a half day tank really, as it holds about 4l. I am used to topping up before starting a journey. Dip pipe is right at the bottom.

 

@Tonka I am fairly dense when it comes to engines, I assume the lift pump is where the pipe/hose are leading to from the filter?

 

I will attach a photo of the whole system shortly - I can’t resize it to under the attachment limit on my phone 

Sorry to confuse you , I didn't see the day tank bit. So as you have to pump fuel up to the day tank by hand I assume which then feeds the engine by gravity then your engine doesn't have a lift pump. Hope that makes sense

[jtylr]

Here is photo showing the whole setup (in the middle of prepping bilges for painting)

 

[Tony Brooks]

I can confirm that thing is a filter.

 

I  think I can't see a lift pump. The injector pump seems to be to the rear of what  take to be the oil filler. It seems to be graivty fed.

[jtylr]

10 minutes ago, Tony Brooks said:

I can confirm that thing is a filter.

Yes, that’s the injection pump. I stopped by UCC when bringing the boat north and Jonathan Hewitt kindly spent some time talking me though the engine.

 

Is there better options for filter(s)?

 

 

[Alan de Enfield]

22 minutes ago, Tony Brooks said:

I can confirm that thing is a filter.

 

I  think I can't see a lift pump. The injector pump seems to be to the rear of what  take to be the oil filler. It seems to be graivty fed.

 

"Day tank" top RH corner of the photo gravity feed to water separator / filter.

 

27 minutes ago, jtylr said:

Here is photo showing the whole setup (in the middle of prepping bilges for painting)

 

Do you do a daily water-trap drain down ? (brass screw, open a few turns and water dribbles out, when you get diesel and no water tighten the screw back up)

 

 

4 minutes ago, jtylr said:

Is there better options for filter(s)?

 

 

You can go 'overboard' as my builder did :

 

Diesel filters as the 1st stage, then under the engine thru a separator (the same as yours) into the pump and out of the pump and into the injector pump.

 

 

 

 

Edited June 21, 2022 by Alan de Enfield

[jtylr]

2 hours ago, Alan de Enfield said:

Do you do a daily water-trap drain down ? (brass screw, open a few turns and water dribbles out, when you get diesel and no water tighten the screw back up.

 

Nope, but I will do now! Just let 210ml of water out of it, thanks for the tip!
 

So I have separator -> filter -> injection pump, gravity fed.

 

As gravity fed does this remove the risk of engine sucking air/fuel from the line to heater as mentioned by @Tony Brooks further up? 
 

 

Edited June 21, 2022 by jtylr

[Tony Brooks]

1 minute ago, jtylr said:

Nope, but I will do now! Just let 210ml of water out of it, thanks for the tip!
 

So I have separator -> filter -> injection pump, gravity fed.

 

As gravity fed does this remove the risk of engine sucking air/fuel from the line to heater?
 

 

 

No, you have a filter that can clog acting as a water trap (agglomerator) > filter > injection pump/.

 

As there is no lift pump and that primary filter is under the day tank head it makes sucking air very much less likely.

[jtylr]

Thanks for clarifying  @Tony Brooks

 

I think I will replace this with the double mounting type and fit agglomerator + sedimenter and run 1 line to engine and 1 to heater as this minimises number of filters.

 

It will all be easily accessed so can tap the tank if any problems occur.

 

 

[blackrose]

I also have a CAV/Delphi water/sediment trap and then fuel filter on the fuel feed to my engine. When I recently fitted a new diesel heater I just fitted another dedicated CAV/Delphi unit. They're fairly cheap, easy to fit and they work well. New elements are cheap too. There would be very little benefit in trying to use the same filter for both engine and heater and it seems a few potential disadvantages. 

[Tony Brooks]

11 minutes ago, jtylr said:

Thanks for clarifying  @Tony Brooks

 

I think I will replace this with the double mounting type and fit agglomerator + sedimenter and run 1 line to engine and 1 to heater as this minimises number of filters.

 

It will all be easily accessed so can tap the tank if any problems occur.

 

 

 

As far as I know all filters will act as agglomerators, so at present you have two filers in the engine supply. If it were not for your wish to run the heater from that filter I would suggest just changing the body to accept the sedimentor parts. These are very unlikely to block. However, As you wish to run the heater from it, I would not change anything, but change both filters during an engine service and drain the one in question every week and modify that period when you see how much water it traps - if any.