Diesel fuel lines, filters and the rules ...

[T_i_m]

Hi all,

 

Following on from me learning another facet of my friends CC 71' NM, I am now set-up to run the Webasto diagnostics and we currently have his Thermo Top C in bits and have (ironically) diagnosed a faulty dosing pump.

 

Faulty in that whilst it seems ok electrically, the solenoid / piston moving electrically the same as when you mode the piston manually with a fine rod pushed into the outlet, it doesn't seem to pump diesel.

 

Wanting to try to understand better how these particular dosing pumps actually work, I was pointed to Youtuber who had sectioned one and I have since asked him if he could see mow the valves actually work and so therefore I might better see if they could have failed because of some debris getting in them and if they might be flushed out. That in comparison with a rubber based valve that has simply worn out. The YT'er has replied and said he will investigate further when back with the pump.

 

I now have a cheap replacement (12V/ 65ml) that I hope to bench test soon but with a genuine replacement being £378.95 (WTF!?) I'd like to fix the original if possible as it feels much heavier than the cheap replacement.

 

Now, if it turns out it is blocked / damaged because there was no filter between heating tank and TTC, what could we get away with re the rules and adding a filter please? I ask because I think I understand that the fuel pipe should be metal (typically copper) but can be joined using short rubber sections and clips, so, what of a plastic bodied in-line filter, would that be 'allowed'?

 

I could cut the copper pipe between tank and pump and fit an in-line filer using a couple of rubber hose sections and clips (do you put a flare on the copper pipes, similar the the end of the pump and heater nipples as I could probably add bubble flares using my brake flaring tool?) if that would be acceptable and it would be much easier to do that than mount a larger metal bodied / replaceable cartridge type filter. He pulled it all out and I think he's going to need me to put it all back but I'm not sure if I can (poor access and me 6'2" etc). ;-(

 

Just trying to get a feel of what the panel suggests please ...

[Alan de Enfield]

11 minutes ago, T_i_m said:

Just trying to get a feel of what the panel suggests please ...

 

Seeing as having a filter with a 'plastic' drain screw, or a filter with a 'plastic' bowl is forbidden I wouldn't think that a plastic inline filter would be acceptable.

 

Mind you with my history of BSS examiners I doubt that :

1) they'd even know that a plastic filter was fitted ( they wouldn't even look in the engine hole)

2) they'd even know that plastic wasn't allowed.

[Tony Brooks]

12 minutes ago, T_i_m said:

Hi all,

 

Following on from me learning another facet of my friends CC 71' NM, I am now set-up to run the Webasto diagnostics and we currently have his Thermo Top C in bits and have (ironically) diagnosed a faulty dosing pump.

 

Faulty in that whilst it seems ok electrically, the solenoid / piston moving electrically the same as when you mode the piston manually with a fine rod pushed into the outlet, it doesn't seem to pump diesel.

 

Wanting to try to understand better how these particular dosing pumps actually work, I was pointed to Youtuber who had sectioned one and I have since asked him if he could see mow the valves actually work and so therefore I might better see if they could have failed because of some debris getting in them and if they might be flushed out. That in comparison with a rubber based valve that has simply worn out. The YT'er has replied and said he will investigate further when back with the pump.

 

I now have a cheap replacement (12V/ 65ml) that I hope to bench test soon but with a genuine replacement being £378.95 (WTF!?) I'd like to fix the original if possible as it feels much heavier than the cheap replacement.

 

Now, if it turns out it is blocked / damaged because there was no filter between heating tank and TTC, what could we get away with re the rules and adding a filter please? I ask because I think I understand that the fuel pipe should be metal (typically copper) but can be joined using short rubber sections and clips, so, what of a plastic bodied in-line filter, would that be 'allowed'?

 

I could cut the copper pipe between tank and pump and fit an in-line filer using a couple of rubber hose sections and clips (do you put a flare on the copper pipes, similar the the end of the pump and heater nipples as I could probably add bubble flares using my brake flaring tool?) if that would be acceptable and it would be much easier to do that than mount a larger metal bodied / replaceable cartridge type filter. He pulled it all out and I think he's going to need me to put it all back but I'm not sure if I can (poor access and me 6'2" etc). ;-(

 

Just trying to get a feel of what the panel suggests please ...

 

Unless the filter is marked to show it is suitably fire-resistant (the BSS manual gives details) I believe it should fail the BSS. The same goes for the hose. However, I have seen it claimed that this does not apply in the engine compartment, but I would not risk it.

 

Any sort of flair should be fine to prevent the hose pulling off the pipe, but bubble flairs will be easier to get the hose over.

[Momac]

14 minutes ago, T_i_m said:

Hi all,

 

Following on from me learning another facet of my friends CC 71' NM, I am now set-up to run the Webasto diagnostics and we currently have his Thermo Top C in bits and have (ironically) diagnosed a faulty dosing pump.

 

Faulty in that whilst it seems ok electrically, the solenoid / piston moving electrically the same as when you mode the piston manually with a fine rod pushed into the outlet, it doesn't seem to pump diesel.

 

Wanting to try to understand better how these particular dosing pumps actually work, I was pointed to Youtuber who had sectioned one and I have since asked him if he could see mow the valves actually work and so therefore I might better see if they could have failed because of some debris getting in them and if they might be flushed out. That in comparison with a rubber based valve that has simply worn out. The YT'er has replied and said he will investigate further when back with the pump.

 

I now have a cheap replacement (12V/ 65ml) that I hope to bench test soon but with a genuine replacement being £378.95 (WTF!?) I'd like to fix the original if possible as it feels much heavier than the cheap replacement.

 

Now, if it turns out it is blocked / damaged because there was no filter between heating tank and TTC, what could we get away with re the rules and adding a filter please? I ask because I think I understand that the fuel pipe should be metal (typically copper) but can be joined using short rubber sections and clips, so, what of a plastic bodied in-line filter, would that be 'allowed'?

 

I could cut the copper pipe between tank and pump and fit an in-line filer using a couple of rubber hose sections and clips (do you put a flare on the copper pipes, similar the the end of the pump and heater nipples as I could probably add bubble flares using my brake flaring tool?) if that would be acceptable and it would be much easier to do that than mount a larger metal bodied / replaceable cartridge type filter. He pulled it all out and I think he's going to need me to put it all back but I'm not sure if I can (poor access and me 6'2" etc). ;-(

 

A plastic drain in a metal fuel filter is not permitted so I would have thought a plastic fuel filter would not be permitted.

However I believe metal inline filters are available.

The fuel pipe does not need to be entirely in metal. A rubber fuel hose is acceptable with the requirements being as below.....

 

But really are you sure the filter is necessary and shouldn't  a possible contaminated fuel issue be investigated?

https://www.boatsafetyscheme.org/requirements-examinations-certification/private-boat-requirements/

 

[T_i_m]

32 minutes ago, Alan de Enfield said:

 

Seeing as having a filter with a 'plastic' drain screw, or a filter with a 'plastic' bowl is forbidden I wouldn't think that a plastic inline filter would be acceptable.

 

Mind you with my history of BSS examiners I doubt that :

1) they'd even know that a plastic filter was fitted ( they wouldn't even look in the engine hole)

2) they'd even know that plastic wasn't allowed.

Hi Alan and thanks for that. If I'm involved in anything like that I would be pushing to do what was right, rather that what we could get away with. 😉

13 minutes ago, Momac said:

A plastic drain in a metal fuel filter is not permitted so I would have thought a plastic fuel filter would not be permitted.

However I believe metal inline filters are available.

The fuel pipe does not need to be entirely in metal. A rubber fuel hose is acceptable with the requirements being as below.....

 

But really are you sure the filter is necessary and shouldn't  a possible contaminated fuel issue be investigated?

Thanks for the reply and info Momac.

 

So (me being lazy but also you guys often have a real world take on 'the rules') can we assume that the rubber hose couplings between pipe from the tank to the pump and hose to pipe to heater, and hose joining it to heater, all conform to BN ES ISO 7840 (and can't be just ISO 8469 as this hear IS fitted in the engine space) and if that is that case and given the distance from the tank to the pump is maybe 400mm and pump to heater about the same, could it all be rubber?

 

I mean, ITRW I think there could be more issues for one of many joints coming undone (and causing problems) than a fire in the engine bay being made worse because of an extra 800mm of rubber fuel line?

 

Ok, if the fuel line needed to run right round the engine bay and especially if there was any chance of it coming in contact with something hot, it makes good sense to run it in metal but in this case, it's right in the comer between the hull and whatever you call the 'cheeks' in the hull either side of the prop?

55 minutes ago, Tony Brooks said:

 

Unless the filter is marked to show it is suitably fire-resistant (the BSS manual gives details) I believe it should fail the BSS. The same goes for the hose. However, I have seen it claimed that this does not apply in the engine compartment, but I would not risk it.

 

Any sort of flair should be fine to prevent the hose pulling off the pipe, but bubble flairs will be easier to get the hose over.

Hi Tony and BSS points noted (thanks).

 

I think the best flair I could make in a bit of 3/16 copper pipe would be a DIN 'bubble', because of it's square back shoulder (acting like a barb), followed by an SAE bubble with it's more tapered back shoulder.

[Momac]

1 hour ago, T_i_m said:

can we assume that the rubber hose couplings between pipe from the tank to the pump and hose to pipe to heater, and hose joining it to heater, all conform to BN ES ISO 7840 (and can't be just ISO 8469 as this hear IS fitted in the engine space)

That is how it reads .

I am thinking a simple inline filter or any filter at all is probably best avoided.

I have also vaguely recalled that the fuel pipe or hose for a diesel heater needs to be a certain small bore otherwise the fuel pump may not be able to draw the fuel.

Edited March 26 by Momac

[T_i_m]

1 hour ago, Momac said:

But really are you sure the filter is necessary and shouldn't  a possible contaminated fuel issue be investigated?

 

Sorry, I think I forgot to reply to this bit ... we don't know that the fuel is contaminated, just that 1) the boat is 20+ years old and I'm not sure I would expect such a plain steel tank to not have some level of corrosion in it and 2) nearly everyone who responded to the issues with the TTC failing have stated that a filter was important to reduce the risk it blocking the vaporiser. 

 

3), Just before the heater failed he added some (red) diesel manually (from borrowed containers filled at a local supplier and ) rather than the more usual way, via the fuel boat. I'm not sure if he actually ran out and that's why he took that option ... or that the heater was playing up and he wondered if it was a fuel level issue or what. <shrug>

8 minutes ago, Momac said:

That is how it reads .

I am thinking a simple inline filter or any filter at all is probably best avoided.

I have also vaguely recalled that the fuel pipe or hose for a diesel heater needs to be a certain small bore otherwise the fuel pump may not be able to draw the fuel.

I deffo got the feeling that not fitting a filter was a bad thing, suggesting that those fitters who didn't were asking for trouble down the line (several YT videos of people repairing systems and retro fitting filters).

 

I assume the existing fuel line setup must have been generally ok given it's been working for a good few years now (with no sign of the heater being serviced in the last 10 my mate has owned the boat) and knowing how the pumps / heaters work (a fixed volume of diesel injected per pulse from the controller), I would have though you might need to ensure there was no additional back pressure that might impact that flow?

 

And the back pressure (into the burner unit) was how one repairer determined if the atomiser was blocked or not. This one seemed to react more like the new one the guy showed than the blocked one.

 

Some of the after-market pumps (and even the current Webasto replacement) come with the equivalent of an accumulator but they aren't needed on the TTC.

 

[blackrose]

I installed a CAV/Delphi water separator/sediment filter with a metal bowl and drain screw between my tank and Webasto. Some here said it wouldn't work, I'm not sure why they thought that, but it's fine. I'm not sure if that's the element I've got in mine. I thought it was the 296, sorry can't remember?

 

 

I also used a proper flexible fuel hose for the final connection to the heater. It's marked with the relevant coding. I think the Webasto manual required 2mm ID pipe but the smallest ID fuel hose that I could find was 3mm so I used that. It's been inspected and passed the BSS twice. 

Edited March 27 by blackrose

[Tonka]

When I installed my Thermotop I used the proper Webasto fuel filter, Copper pipe which I flared using a brake pipe flarer. Also Diesel marked flexible pipe  plus clips

[blackrose]

11 hours ago, Alan de Enfield said:

Mind you with my history of BSS examiners I doubt that :

1) they'd even know that a plastic filter was fitted ( they wouldn't even look in the engine hole)

2) they'd even know that plastic wasn't allowed.

 

I think you must have been very unlucky with inspectors. All the inspectors I've had onboard have checked my fuel lines and the drain screws on both CAV/Delphi filters. I also have one on the fuel line to the engine.

[Jen-in-Wellies]

I installed a standard CAV filter and water separator in the fuel line to an Eberspacher. Used compression fittings to the 4mm pipe, then BSP to 1/2" UNF adaptors to fit to the filter.

[T_i_m]

1 hour ago, blackrose said:

I installed a CAV/Delphi water separator/sediment filter with a metal bowl and drain screw between my tank and Webasto. Some here said it wouldn't work, I'm not sure why they thought that, but it's fine. I'm not sure if that's the element I've got in mine. I thought it was the 296, sorry can't remember?

 

 

I also used a proper flexible fuel hose for the final connection to the heater. It's marked with the relevant coding. I think the Webasto manual required 2mm ID pipe but the smallest ID fuel hose that I could find was 3mm so I used that. It's been inspected and passed the BSS twice. 

That unit looks quite tall and that may be why a filter wasn't fitted in the first place.

 

The fuel tanks seem to be across the inside of the transom and round the stern un a 'U' and is / are split into two unequal sizes, large for engine, smaller for heating with two fillers one on either side of the stern deck / gunwale.

 

 

I've not checked the engine fuel line (on the port side) but given the top of the engine is around the level of the bottom of the balcony bit that hangs over the prop / rudder / skeg (what is that bit called please?) there is a very clear gravity path between even the bottom of the fuel tank and engine, even when the tank is low.

 

The outlet of the heater fuel tank is also just above the balcony with the pump at about the same plane but with the feed into the pump pretty close over the rear balcony. ie, The (copper) fuel line is joined to the tank tap with a compression joint, it then spirals round 3-4 x 3" diameter loops, travels forwards and outwards about 12" to the rubber hose jointer into the horizontally mounted pump, mounted to the vertical metal bracket that is welded to the fuel tank, that then the heater bracket itself bolts to.  The fuel line then comes out the pump (rubber hose coupling) through another set of loops in the copper then up vertically a foot and into the heater with a rubber hose joiner (and clips etc).

 

I think the general idea is that the fuel line rises from the tank to help the air get out of the system and to minimise the chance of airlocks so I guess if we were starting again, we would mount the filter near to the tank outlet so the pipe rises up to the height of the filter. The outlet of the filter would then carry on (slightly) up to the pump and then from the pump, up to the heater. The problem with that is we would have to be mounting the filter onto the fuel tank or onto the heater, or a metal plate / bracket bolted to the heater?

 

That might be doable and would at least bring the filter and pump towards the centreline of the boat a bit and so slightly easier to access.

 

All more engineering work than I really have time / capacity for. ;-(

1 hour ago, Tonka said:

When I installed my Thermotop I used the proper Webasto fuel filter, Copper pipe which I flared using a brake pipe flarer. Also Diesel marked flexible pipe  plus clips

 

Thanks. I think that filter is fairly compact, so likely easier to fit and would be more 'approved' (by Webasto) for use with these heaters.

 

I think it might be one of those jobs where you get all the bits (heater / pump / filter) lined up and then join them the best you can?

[Jen-in-Wellies]

There are small metal can filters used in vehicles that should be BSS compliant and fit in a much smaller space than the typical CAV. Similar to the plastic, or glass body ones. They won't separate water out, but would filter out the particles that could block the pump, or heater. Typical example:

https://www.merlinmotorsport.co.uk/p/sytec-fuel-filter-8mm-in-and-out-with-bracket-ssfc5160c

[T_i_m]

1 hour ago, Jen-in-Wellies said:

I installed a standard CAV filter and water separator in the fuel line to an Eberspacher. Used compression fittings to the 4mm pipe, then BSP to 1/2" UNF adaptors to fit to the filter.

 

I like the idea of a water separator, given the fillers are horizontal and I'm guessing would get some ran in there if filled when raining (plus any water in the supply boat tanks etc).

 

Dad, an Ex Merchant Navy master on tankers told me that after discharging oils they generally purge the pipes with compressed air. When purging the likes of petrol they use water (because of the increased risk of ignition etc) and so why there often is water in petrol tanks?

2 minutes ago, Jen-in-Wellies said:

There are small metal can filters used in vehicles that should be BSS compliant and fit in a much smaller space than the typical CAV. Similar to the plastic, or glass body ones. They won't separate water out, but would filter out the particles that could block the pump, or heater. Typical example:

https://www.merlinmotorsport.co.uk/p/sytec-fuel-filter-8mm-in-and-out-with-bracket-ssfc5160c

Yeah, that looks more doable but I think we would need one with a smaller tail size, like 4mm or so?

 

I'll have a look about, thanks. 😉

[Jen-in-Wellies]

6 minutes ago, T_i_m said:

Yeah, that looks more doable but I think we would need one with a smaller tail size, like 4mm or so?

The link was just an illustration. Get one with BSP threads at the end, then pick hose tails, or compression fittings to suit the hose, or pipe.

The most common source of water in boat tanks is from flush fit deck fillers. The o-ring seal degrades and rainwater gets past.

[T_i_m]

14 minutes ago, Jen-in-Wellies said:

The link was just an illustration. Get one with BSP threads at the end, then pick hose tails, or compression fittings to suit the hose, or pipe.

The most common source of water in boat tanks is from flush fit deck fillers. The o-ring seal degrades and rainwater gets past.

Point about 'choose your own ends' noted thanks Jen. Without wanting to sound like 'Jonny glass half full' here, and given the potential searching power of Google, you often find what you are looking for is rare / expensive. ;-(

 

I learned that early on with clothes. A shirt that fitted me round the neck and was long enough in the arms was like a tent. If it fitted me in the body I couldn't do the collar up and the cuffs would be by my elbows. The good thing about that was that I never got into fashion, just grabbing whatever fitted me whenever I could. 😉

 

 

56 minutes ago, T_i_m said:

Thanks. I think that filter is fairly compact, so likely easier to fit and would be more 'approved' (by Webasto) for use with these heaters.

 

You just need to hope it doesn't get contaminated, at the price of a new element! ;-(

[David Mack]

48 minutes ago, Jen-in-Wellies said:

The link was just an illustration. Get one with BSP threads at the end, then pick hose tails, or compression fittings to suit the hose, or pipe.

The most common source of water in boat tanks is from flush fit deck fillers. The o-ring seal degrades and rainwater gets past.

Filters fir domestic oil fired heating systems are widely available and inexpensive. For example

 

https://www.fueldump.co.uk/product/fag-inline-heating-oil-filters/

 

 

[T_i_m]

6 minutes ago, David Mack said:

Filters fir domestic oil fired heating systems are widely available and inexpensive. For example

 

https://www.fueldump.co.uk/product/fag-inline-heating-oil-filters/

 

 

That (the 1/4" version I think) looks promising David. Just needs a couple of 1/4" BSP to 3/16" tails (or 3/16" compression joints?) and we should be good to go. 😉 

 

So, would we go for the 100 micron stainless mesh or the 15 micron paper element do you think?

[Jen-in-Wellies]

13 minutes ago, T_i_m said:

So, would we go for the 100 micron stainless mesh or the 15 micron paper element do you think?

100 micron would just get the naked eye visible chunks of crud out. This may, or may not remove particles that could block a pump, or jet. 15 micron would be safer.

[T_i_m]

5 minutes ago, Jen-in-Wellies said:

100 micron would just get the naked eye visible chunks of crud out. This may, or may not remove particles that could block a pump, or jet. 15 micron would be safer.

Thanks again Jen. In this case I don't believe there are any jets, just a form of fireproof 'pad(s)' that allow the diesel to spread across the diameter of the burner before vaporising by the heat and burning.

 

TBF, whilst I have seen mention of not having a fuel filter being party to blocking the diffuser, I think it's more likely to be blocked by carbon from the combustion process.

 

 

(View into burner showing the diffuser and glowplug). Whilst that looks pretty grim, it's nowhere near as 'sooted up' as many that stop working but in this case it's likely that it may have burned some of the carbon off as it was probably running lean.

 

One of the Youtube vids that covered the diagnostic and subsequent replacement of the burner unit tested it by blowing into the fuel feed pipe. If it feels like blowing into something that is 100% blocked then it's blocked (if you can't blow air though it then the chances diesel can't get through it either). But even with a new one is was like starting to blow up a tough balloon, where you could just hear the sound of air passing though the mesh etc.

[Tonka]

Bit concerned, did you say that the fuel line for the engine and heater were gravity fed from the tanks, because I thought that was a definite BSS fail

[matty40s]

13 hours ago, Momac said:

That is how it reads .

I am thinking a simple inline filter or any filter at all is probably best avoided.

I have also vaguely recalled that the fuel pipe or hose for a diesel heater needs to be a certain small bore otherwise the fuel pump may not be able to draw the fuel.

Webasto now include an inline fuel filter with all their marine kits(quite similar to the above small alloy filter)

The small bore is indeed necessary, to allow the pump to work effectively. 

[Tonka]

Just now, matty40s said:

Webasto now include an inline fuel filter with all their marine kits(quite similar to the above small alloy filter)

The small bore is indeed necessary, to allow the pump to work effectively. 

Is that the one with a stop valve?

[matty40s]

2 hours ago, T_i_m said:

 given the top of the engine is around the level of the bottom of the balcony bit that hangs over the prop / rudder / skeg (what is that bit called please?) there is a very clear gravity path between even the bottom of the fuel tank and engine, even when the tank is low.

 

Not gravity fed, just a common engine install, most modern engines narrowboats have this arrangement.

9 minutes ago, Tonka said:

Is that the one with a stop valve?

Yes..

[T_i_m]

20 minutes ago, Tonka said:

Bit concerned, did you say that the fuel line for the engine and heater were gravity fed from the tanks, because I thought that was a definite BSS fail

Erm, the heater pump (that I believe also doubles as a stop valve) is definitely gravity fed, not sure about the engine (I just assumed it would be) but I'll check when there next.

17 minutes ago, matty40s said:

Not gravity fed, just a common engine install, most modern engines narrowboats have this arrangement.

Yes..

Thanks for that Matty as if that's the approved Webasto filter it also answers another question, '44 micron'.

 

Is that a spare / working pump in the background and if not, do you want to sell it for me to cut open?