I just bought 3 MEP002As and 2 of them were missing the 1/4" pipe nipple, check valve and 90-degree JIC elbows. (I wonder if these were pilfered at the base or did the last maintenance crew just forget to reinstall them.) Anyway, I plan to install a commercial check valve (Airtex brand) Advance Auto #CV 8000 or NAPA AFP CV8000, price $12-$15 each. This piece is brass with female 1/4" NPT threads. (I have no idea how this valve relates to a size 5 mentioned in the post.) From this I will install two 90-degree elbows with 1/4" NPT to go into the check valve and at the other end 37-degrees JIC with a thread size to fit the existing fuel hoses--I believe its either 5/16" or 3/8". I brought the existing hose to NAPA today so I just matched the thread size to fit the JIC fitting on my hose.
BTW, the brass JIC fittings (90-degree) were pricey at abt $11 each. I bought (4) to set up the two MEPs that were missing the fittings. Hope this all makes sense. One more thing--I posted a question yesterday about this same subject (not knowing the check valve was needed), but I failed to ask about the direction the check needs to be installed. Since the line in question appears to be a supply hose (coming off the 3rd filter), my assumption is that the check needs to be installed to allow fuel flow to the IP.
