High Fuel Pressure - Air Flow Boost Pump

[B737NG]

Hello,

My Air Flow Performance Boost Pump is putting out greater than 40 psi, confirmed with two different guages. I pulled apart the Kepner Check Relief Valve to have a look.

There is a retainer ring that holds the O-ring in place. The retainer ring is "cupped" or shaped like a bowl. For anyone who has had the relief valve apart should the o-ring sit in the top of the "cup" or bowl (large dia of the ring) or does the larger end of the retainer ring point towards the spring?

Thanks for your help!

Paul

[B737NG]

It turns of the retaining ring was installed backwards in the Kepner relief valve.

I turned it around so the O-ring sits on the top of the retaining ring and I am now seeing 24.8 psi with the electic boost pump on.

Paul

[rzbill]

Your experience appears to fly in the face of the severe documentation that comes with the pump stating they have been factory tested and as a result no warranty is provided.

I'm already well down the path, but if I had known up front about the warranty aspect, I might have chosen a different route.

[RVG8tor]

Originally Posted by B737NG

It turns of the retaining ring was installed backwards in the Kepner relief valve.

I turned it around so the O-ring sits on the top of the retaining ring and I am now seeing 24.8 psi with the electic boost pump on.

Paul

Did you contact API to report your issue, did they suggest this fix? I just wonder who else might have a defective part, if you give them your units serial number then they might be able determine if a bad batch were produced. Seems prudent to let them know.

Cheers

[frankh]

One of mine makes 40 psi and the other 35psi..The AFP servo is good to 90psi so it really does'nt matter, but less pressure is nice from a safety perspective

FRank

[AirbusPilot]

I bought an Airflow Performance from Van?s for my RV-8, but I don't like the looks (no better than a car one made in China) and don't like also all guaranty warnings, don't unscrew, don't cut wire, don't touch, bla bla bla. So went I found the new pump made by Andair and they give me 5 year warranty no matter what, I went with them, better looks (like a real aircraft boost pump), cleaner installation.
Anyway my plane is not flying yet so I can not speak about reliability

[frankh]

One of mine makes 40 psi and the other 35psi..The AFP servo is good to 90psi so it really does'nt matter, but less pressure is nice from a safety perspective

FRank