Specs from the Simpson book show a great range so not really critical. It says the inlet valve is capable of working at 30 to 1400 kPa which is 4 to 200 psi.
Lincoln Appliance NZ
October 2009
I can answer this question...
What is the water pressure needed on a simpson encore 704?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix washing machines.