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912iS Check Valve installation CAUTION

I’m replacing my $135 FUEL-CK375-NM-BRP check valve on the advice of Van’s.

The step covering the installation is KAI 27iS-03 Step 4 : “Assemble the fuel filter assembly, fluid fitting, FUEL-375-NM-BRP (check the flow direction)…” and also Section 5.27 Pipe Thread Fittings (using Locktite 565):
“. ..Thread the fitting in with your fingers until you just begin to feel resistance and then an additional 1.5 - 2 turns. This is a general guideline… you must still use judgment to not over tighten and damage the threads, but a properly installed fitting is quite tight...”

And noting no cautions about the delicate nature of this part in the step or the Andair packaging, I believe I installed the part correctly. This was reinforced by the Andair packaging which noted the part was “Machined from Aluminium L168” implying premium material and manufacturing.

Having had to really torque the other tapered fittings in the fuel system (fuel pump area), I thought it best to use a 6 point socket on the outlet side rather than a wrench to engage just 2 flats on the input side (both ends have 6 flats on a hexagon).

BAD MOVE!
Better move: tighten using the flats closest to the attaching part.

One turn felt tight enough. I took the socket off and notice a number of slanting wrinkles in the metallic label covering the part. Thought – that doesn’t look right! This looked like rotational motion between two halves (couldn’t tell there WERE two halves) and I thought, have I ruined this check valve?

I sent an explanation and picture to Support and they reached out twice to Andair who never answered. Support said they were unable to give this part a clean bill of health not knowing the inner workings of it. They recommended error on the side of caution and replace.

This GOTCHA should be warned about in the KAI because it’s way too easy to ruin an expensive part. Only took a second.
 
Have you checked the manufacturer website? Some have spec sheets with cutaway drawings. Maybe not this one, but a quick google search might resolve your concerns.
 
I damaged my check-valve in the same way.. not knowing there were two halves of it. As soon as I saw the wrinkling of the metallic sticker on it.. i stopped. The two halves rotated only.. maybe less than 1/4 cm.. just enough to see the label wrinkle. I didn't think anything of it and continued building. It hasn't been a problem.
 
Thanks for sharing your hard-earned experience! I'm not far from doing this step, and I can see myself doing something similar...
 
Thanks Rich, I checked Andair's web page and found this:
From their website at http://www.andair.co.uk/category/check-valves/

================================================== ==
"The Andair Check Valve is a complete closure valve. It allows fluid to pass in one direction whilst preventing it from flowing in the reverse direction. Arrows on the outside of the body indicate the flow direction. The valve is machined from L168 Aluminium and then anodised for greater protection. To connect to the valve a range of fittings are available.
Optionally a bleed can be fitted to the valve at no extra cost, here the internal shuttle has been drilled with two small holes. This allows for bleed back to occur. This particular valve is useful in the vent line of a fuel system where allowance for fuel expansion is necessary.
The internal shuttle and spring are extremely light giving a cracking pressure of between 0.4-0.7 PSI. Optionally, a cracking pressure of between 12-17 PSI (0.8 - 1.2 Bar), suitable for the Rotax 912iS is available (£8.00 extra)."

Also some recalls on some other things, but that's all for the check valve.

Rob,
I measured mine and thing it turned maybe 0.34 cm (0.135 inch) or 36% more than yours, if I got it right. Didn't feel like anything was yielding, so even at that it might have been OK.
The new check valve came today, so now I can wrap this fuel line plumbing up. Did you have any leaks to deal with?
Thanks,
John
 
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