Westwind pressurization problem











The valve opens correctly with shop air applied, and the controller  disconnected, and slight vacuum applied to control circuit





Front valve will open when control i connected straight to the pneumatic relay.




Ground prepress seems to work correctly





Aircraft pressurizes hard on the ground, straight to 3 psi at idle.  Fwd valve will not open via the controller.


Turns out the limit valve was failed.  It had opened because the pilots got the cabin to 17,000 feet.  Then the brass seat fell out of place.  Then valve leaked from then on .





Removed failed altitude limit valve PN 102466-1  SN 88-2322.  Installed serviceable valve received on form.   PN 102466-1   SN 17-1898






Removed failed anti-ice pressure reducing valve PN 38E59-1D  SN 2907 -U. Installed Ovrrhauled valve recieved on AVITECH W.O. 1021932 PN 38E59-1D  SN RF3502.