Dual filter

Roberto

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I have a 50hp Perkins 4108 fitted with a water separator filter of unknow origin, possibly a cav one, or very similar.
I would like to fit a racor filter in parallel, with a Y shutoff valve to be able to use one filter or the other (for ex while changing a cartridge underway), model 120 seems ok as it has a flow rate of 57 liters per hour.

Does it seem a sensible thing to do ?

I cannot see any problems in using two different filters as they will not be used together, is there anything to worry about?

I am also thinking about fitting a vacuum gauge after the two filters, which will indicate if clogging is taking place: is this useful or is it overkill?

thanks
 

pvb

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Maybe consider...

Racor filters are good, but it might be better to consider adding a second identical filter/separator - that way, you only have one type of spare filter to keep on board.

You may well have one of the CAV-type filter/separators now, they're very common and filters are cheaply available everywhere. They look like this:-
302003.jpg


I have two of these with taps so that either or both can be in circuit. Separate taps are preferable to a Y-valve, so that you can use both filters together if you need to. You'll have to have taps on the inlet and outlet of each filter if you want to be able to change the cartridge whilst under way. Remember too that you'll only be able to bleed the air out of the replaced cartridge if the fuel tank is above the filter, or if you add a pump device. Otherwise you'll have to stop the engine and use the fuel lift pump to bleed the new cartridge.

I've also installed a vacuum gauge, and find that it's a useful indicator of when the filter needs changing. It's a Racor gauge, and is very easy to fit.
 

pappaecho

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Lifeboats have two fuel filters by default, so that any suggestion of a blockage, they switch to reserve.
I have just overhauled a separator (CAV) from a 4108 installation, which was the first time it was servced in 7 years - there was not a lot of sediment in the separator, and what there was... was stuck to the dish shaped collector. I also as a matter of interest, removed and dissected the CAV fuel filter fitted to the 4108, and again there was little evidence of serious build up of muck.
On this basis, assuming that you have clean fuel, I suggest that just a yearly check, will be more than adequate. I was quoted £25 plus vat for a Racor separator and prefilter, but decided that it was too much hassle to fit, ... the tappings are metric and the 4108 is imperial/Unified threads etc.
 

Coppershield

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Hi Roberto,
RACOR filters may be easier to find, however , as someone else stated earlier , having identical filters are definitely tempting.
I would not have a filtering system without the vacuum gauge; I know before I installed gauges . most filters that I discarded was probably good for another 50 hours or more, however , if You get a bad batch of fuel vacuum gauge will give You early warning. While You're at it You may also consider installing water sensor , as well as installing a auxiliary pump on the discharge side of the filter this pump will allow You polish your fuel and also when You change a filter will make purging the air very easy. Once I changed a filter in less than Two minutes.
If You need more information please let me know.
Good luck :) .
Muzaffer
 

FlyingDutchman

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Interesting.
I am considering doing the same thing, our boat is equipped with the CAV HDF 296 filter as described in pvb's answer and I have another (new) one at home which I could install. My problem is, I don't know what valves to use. Any input most welcome!
 

pvb

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Suitable valves...

You can use good-quality lever operated ball valves, which look like this:-
405752.jpg

Perhaps the easiest way of constructing the copper piping is to make a separate plywood mounting board for the filters and valves. You can then do all the "plumbing" work at home, and then mount the complete dual filter assembly in the boat and finally connect the inlet from the tank and the outlet to the engine. Remember to allow enough space under the filters for servicing access. Although purists may frown on it, it's probably worth sealing all the joints with a diesel-resistant compound - there are lots of joints, so lots of opportunities for tiny air leaks which will be difficult to find at a later date.
 

Roberto

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thanks all,

so the system should be:

pipe from the tank--> Y fitting creating two legs-->two shut off valves on each of the legs--->parallel filters--> two shut off valves on the "out" pipes of each filter-->another Y combining the two pipes into one-->vacuum gauge--->pump--->Y valve with one exit to the engine and another one connected to return fuel pipe to tank

does it seem correct ?
 

FlyingDutchman

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Re: Suitable valves...

Thanks pvb!
I have considered these type of valves, but I am afraid air can be trapped inside and also the mounting is not so easy. The idea of a separate board to mount the whole assembly at home is brilliant! Never thought of that!

PS: SWMBO gave me the GPS 152 for my birthday last week. Thanks again for your advise! Trying to go through the manual, but it does seem rather complex. Even hooked it up to a battery in the living room to experiment a little!
 

pvb

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Mounting valves...

You can get neat little brackets to mount the valves. Look like this:-
405951.jpg


If you contact someone like ASAP Supplies, they'll be able to advise you and supply all the valves, joints, pipe, etc, that you'll need.
 
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