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How to service and/or fit a replacement diaphragm to the Alfons Haar type SF1 inflation valve

The Alfons Haar SF1 is a high quality, high performance RIB inflatable boat inflation deflation valve that is fitted to the RNLI’s Atlantic Class RIB inshore lifeboats and other military and high-level commercial specification boats.

The SF1 valve is simple to maintain and service and ribstore are able to supply both complete SF1 valves and service diaphragm kits – visit


Alfons Haar SF1 inflation valveServicing the Alfons Haar SF1 Inflation Valve
Remove the cap. Deflate the tube or collar by twisting the brass diaphragm spindle anti-clockwise a ¼ turn and depress the spindle down until it is in the locked open position. Remove and keep safe the black rubber seal (do not unscrew the upper valve body as the lower valve body may be lost inside the collar/tube).


Using a pair of circlip pliers, remove the large gold coloured circlip from the body of the valve. Slide the complete spindle/diaphragm assembly up and out from inside the valve body.

Alfons Haar valve Alfons Haar valve components

Inspect the rubber diaphragm for any damage, dirt and/or grit, or for any hardening of the rubber that prevents a good seating of the valve. Ensure that the spindle is in the closed valve position and depress the brass spindle to check the free operation of the spring. Inspect for any damage of the brass spindle, spring and plastic fittings. If any damage or failure to freely operate, replace the diaphragm assembly (service kit available at Otherwise clean the diaphragm assembly with soapy water and when dry reassemble the valve. Ensure that the spindle is in the closed position before re-inflating and replacing the cap.

Alfons Haar valve cross-section


View & Download a PDF Version of this Guide HOW TO service a Alfons Haar SF1 inflation valve