Re: BigKev

Posted by HH56 On 2022/10/11 13:51:43

As I understand it, A is the vacuum source and vacuum is also connected thru a passage in that solenoid assy and passed thru to B and via the short hose to C. When the button is pushed the solenoid activates and vacuum is admitted to the large piston section to pull the piston up against the heavy spring. Never tested to see if the vacuum is temporarily blocked at B when the solenoid is active but at any rate, when the large vacuum side piston moves up it also sucks water up into the small piston side water chamber.

When the button is released, the solenoid again blocks vacuum to the large piston and at the same time readmits air so the spring can start to push the piston assy down and expel the water. Vacuum is again (or maybe still) present thru the hose at C.

As water starts to discharge thru the separate coordinator valve section it pushes against the bottom of a rubber diaphragm or valve assy before it exits at D and goes to the nozzles. As the rubber diaphragm is pushed up by the water from below it also causes a port in a section above the diaphragm to open and let the vacuum present at C pass thru to E and on to the coordinator. Vacuum then pulls the coordinator piston back against a spring and starts the motor.

As the water is exhausted from the small piston chamber, flow diminishes and the diaphragm is no longer held open so vacuum to the coordinator is stopped. With no vacuum the spring in the coordinator can push the piston back and stop the motor. The length of time this takes is controlled by how fast the air bleed screw on the end of the coordinator lets the piston move. As I recall, instructions say adjust for 3 or 4 wipes after the water stops and to be careful not to bottom the adjust screw if trying for more wipes because the bleed valve can be damaged and not function if you do.