Racor 500ma Installation

Bill1565 · Mar 24, 2014

sailingguy2005 said:
Would anyone know if i could use threaded copper fittings and pipe to install a Racor 500ma? And if so, what to use on the threads between the unions. I think desiel will detiriorate Teflon tape? I'm planning on making a loop with shut-off valves so I can by-pass the racor and change the filter on the fly. The loop will be hard piped and I will use fuel hoses both, from the engine to the loop, and from the fuel tank to the loop. Any info with be greatly appreciated. Thanks, John S/V - Annie Eileen

Always used fuel hose, don' t know why you would want copper for this.

capta · Mar 24, 2014

I always use Indian Head Shellac on fuel pipe connections. Right or wrong, it does the job and I've never had a joint done this way leak.
But I agree with Bill1565, why, for this application, would you want to use pipe? But the bigger question is if you are only using a single filter, why would you want to bypass that filter? Filters need to be changed as regularly as your system requires and what you are proposing goes against the "Black Box Theory" in it's entirety.

Maine Sail · Mar 24, 2014

In order to use standard NPT pipe fittings on a Racor 500 you first need adapters to get from the Racor to NPT. Any good quality pipe dope rated for fuel oil/diesel, such as Hercules Real-Tuff, will be fine. Always start the dope one thread down..

Chris Patterson · Mar 24, 2014

Yeah, that's so. The fitting that ideally goes into the filter proper are straight, (parallel), threads with an O-ring that compresses with a captured nut, so you can orient the fitting a particular direction if it is angled. No sealant of any kind is used on this type of fitting, the O-ring seals it, and anything put on the threads will just waste tape, dope, or whatever. And make a mechanic snicker quietly when he sees it. And fittings of this type take some seeking, auto people are clueless about them. Hydraulic specialist will be your ally here.

What threads into this adapter on the other hand should be sealed as described.

Maine Sail · Mar 24, 2014

Chris Patterson said:
Yeah, that's so. The fitting that ideally goes into the filter proper are straight, (parallel), threads with an O-ring that compresses with a captured nut, so you can orient the fitting a particular direction if it is angled. No sealant of any kind is used on this type of fitting, the O-ring seals it, and anything put on the threads will just waste tape, dope, or whatever. And make a mechanic snicker quietly when he sees it. And fittings of this type take some seeking, auto people are clueless about them. Hydraulic specialist will be your ally here.

What threads into this adapter on the other hand should be sealed as described.

Yes the straight thread with o-ring do not get pipe dope. Only NPT/NPT get dope.

This is a typical Racor adapter for a 500 series.

http://www.defender.com/product3.jsp?path=-1|311|2349059|2349074&id=1716268

Eric M · Mar 25, 2014

John,
Back to the comment from capta, you don't want to ever bypass your filter. Put a second filter in parallel with your first, this way when one plugs all you have to do is flip your upstream valve, possibly re-bleed the system and continue on your way. After the second time I had to change a filter at sea I installed this setup on our boat and have never had to change a filter underway since.