ACS Free Flow One-Way Check Valve

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Part# 10630
MFR Model#


Prevents return fuel flow during normal operation but provides by-pass fuel feed in an emergency if the fuel pump fails. Wt. 1 oz., 2-7/8" long. Use with tube fittings for 3/8" dia. fuel line. Anodized for corrosion resistance.
Made in USA
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


Leaks when under pressure from the gravity feed of high wing. Requested replacement

Dan K Verified Purchase


April 6, 2024

Order received within 3 days and installed on the airplane on the same day. Exact product as ordered.

Guy S Verified Purchase


September 13, 2023

I replaced my old check valve same part number that was on my aircraft for 10 years, new one works as advertised.

Gary S
March 7, 2020

Installed in a gravity feed system, in parallel with a Facet boost pump. This valve is indeed free flow (zero PSI breakout pressure) and as such works well in the gravity feed system, when the pump is turned off. The pump is only turned on for extreme nose up attitudes.

Chris S
August 4, 2017

The item works great at sealing as a check valve. I had to open up and clean the seats from dust and once clean it worked great. I used it for vent and gas applications.

James E
June 3, 2017

Not as represented, will not operate in light flow conditions

Russell M Verified Purchase


November 5, 2021

It leaked, did not work

John A Verified Purchase


February 15, 2022

Tried two of these. Both leaked and I ended up with fuel all over the floor of my hanger.

Wayne L
December 24, 2017

Failed, wasted $75 worth of fuel on the floor. Was in the upright position.

Stephen P
June 15, 2019

Since it is not spring loaded, it never worked and it was in a vertical position.

Randy F
February 9, 2018


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Does this ACS free flow one-way check valve use -6 AN flare fittings?

Yes, it uses 3/8" tube fittings, which is a -6 AN flare.

Q: What is the mechanism inside the ACS free flow one-way check valve?

Per ACS Products, it is a gravity flow piston. It only allows fuel flow in one direction.

Q: Can this ACS Free Flow One-Way Check Valve be used in any position?

Yes. This is for a free floating application, but can be mounted in any position.

Q: What is the maximum flow rate for this ACS check valve part# 10630?

0 PSI for breakout; 20 PSI max.

Q: Is there a pressure rating on this item? And what are the seals made of?

0 PSI for breakout; 20 PSI max. Seal are made of viton rubber.

Q: What is the interior flapper material (PTFE?)? Is this component rated for fuels containing ethanol?

The piston is made of Delrin and there is no rating for ethanol.

Q: Does ACS check valve 10630 have a bleed function?

No, this product does not have a bleed function.

Q: What are the failure modes which could prevent flow in the forward direction? Have you had any field reports of failure to flow in the forward direction?

We do not have any reports of failure to flow in the proper direction. There is only a plastic piston on the inside and even if it is put in wrong, it will still flow just not stop.

Q: What are dimensions of the ACS free flow one-way check valve? Is valve available with NPT one end and other end flare?

The dimensions are 2-7/8 long. This is not available in any other sizes or modifications.

Q: Is this ACS check valve an FAA/PMAd part approved for use on certified aircraft?

No, the 10630 is not FAA/PMA approved.

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