this is a new machine or you just purchased it used. there is a remote
possibility the pump has no bypass (unloader) valve.
Generally a pump
will only work once if the trigger
gun is shut when there is no unloader or bypass valve on the
pumps are positive displacement, meaning that if the pump turns it has to
pump. If there is no place for the water to go something has to give.
here for more discussion on pumps.
If there is no unloader valve and you
release the trigger on the gun your in for a potential catastrophic
failure. Best case scenario is that your motor or engine will
stall. Worst case is you will see parts flying out of the side of the
pump, hopefully not at your head.
It is absolutely
critical that an unloader valve is installed, unless you are working with an open
system with no shut-off devices downstream from the
here for more discussion on unloader valve.
here for further discussion on protecting your pump.
SOME OF THESE OPERATIONS CAN BE
EXTREMELY DANGEROUS. IF YOU DO NOT HAVE SUFFICIENT TRAINING IN THESE PROCEDURES, WE RECOMMEND YOU
SEEK ASSISTANCE FROM A