Racor Filter Self Venting Drain Puzzle

[RogerJolly]

Folk's anyone know what is meant by 'self venting drain plug' that you get with Racor filters?

Surely you can only vent air from above the liquid, whereas a drain has to be at the bottom.

No explanation in the Racor documentation - useless. Maybe it means it lets air out if there's positive pressure, being pushed out of the lines upstream of the filter, then stops once filter starts filling.

Guess it doesn't matter. I'll just treat it like a normal drain plug - unscrew anti-clockwise to let the fluid out(?)

Many thanks.

 

[SailingDog]

Which Racor do you have ? I've just changed the element in my 500 series, drain at the bottom, no vent as such. Racor have changed the bottom drain in the last few years.

 

[RogerJolly]

It's a 120 AT, simple spin on job. Just bought it so latest thing. Self venting drain came with it as standard. Think you can buy them separately.

 

[Yngmar]

It's just a drain plug. Perhaps by self-venting it means it can let air in (bubbling up) when you drain liquid out, so vacuum in the bowl (when fuel shut-off is closed) doesn't prevent you from draining. Marketing words to help sell a plastic nipple for 25 quid!

 

[RogerJolly]

Ah. Guess they trying to offer something quicker than a series of 'air bubble comes in, bubble's-worth of liquid comes out' then.

I'm thinking I won't drain much at all, just unscrew the bowl and filter together so not much spills, then tip out out at leisure once I've un-contorted myself.

Compare with CAV type, where I guess once you undo the middle bolt all the contents fall out, and in my case of needing to use a shallow drip tray it would be then be more full and likely to spill.

 

[Yngmar]

Cut off 2L water bottle shoved over the whole thing and then squeezed to unscrew should catch most, except the bits that inevitably dribble out of the top.

We've fitted a 500 FG (well, Chinese copy, not made of money) just because it lets you keep the fuel in the thing and only fish the filter out of the top. Inspired by having to change a CAV filter at sea, repeatedly, fuel all over the place and almost popping that vein on the side of my head and wrenching my tongue swearing.

 

[RogerJolly]

Cut off 2L water bottle shoved over the whole thing and then squeezed to unscrew should catch most, except the bits that inevitably dribble out of the top.

Great tip. Thanks Yngmar.

 

[LittleSister]

I wonder whether it might mean that when you drain from the bottom it draws fresh diesel in to replace it at the top of the assembly, but I can't imagine how that would work if the filter were below the level of fuel in the tank.