Magnum Venus Plastech PATRIOT SSB Commissioning and instruction - Manual (Page 15)

SSB_Auto Instructions Issue 05
Page15
10.1 Catalyst pump piston seal.
The SSB model is designed with a new type of internal Piston valve. This new design has
dispensed with the conventional small ball and spring metal to metal types formally common in
the industry.
In the new design the valve action is generated by the fact that the piston assembly has a very
small amount of “slop” or lost motion.
It is essential therefore that during any maintenance on the piston seal the correct lost motion is
set as detailed below and is observed before re assembly after service of this section.
To access the pump piston seal or any other pump internal parts proceed as follows.
Pump out catalyst from system after lifting the filter end of the catalyst feed above the catalyst
bottle level. Continue to pump until air bubbles appear in the return flow glass and then
remove catalyst feed pipe from the inlet to the catalyst pump. This should only be hand tight.
Remove pump guard
Unscrew by hand the lower catalyst block (4282) from pump body.
Unscrew outer tube (0526) the pump cylinder (0525) is now exposed.
Remove this by withdrawing down to expose the pump shaft and piston assembly.
Loosen locking nut 6256 and unscrew the piston retainer M4 screw (5692) using 2.5 AF Allen
key Tthe piston assembly will remain upon the screw as it is removed.
Remove the Piston assembly from the screw and unscrew the piston (4234) from the retainer
bush (4235). Withdraw the piston seal (1712).
Replace with new seal. Observe the correct” lip up” orientation of the seal as detailed on figure
33. Do not force seal onto piston (4234) unevenly. Best results are obtained by placing seal in
position (lip upper most) and hand tightening piston and bush back together. Do ensure
assembly is fully retightened. It should measure 13.5 mm when tightened. Piston valve seal O
ring (5684) may be renewed at this time.