Electric Pressure Washer add Flow Switch and Timer Relay

Thread Starter


Joined Mar 28, 2020
I am looking to invest in an electric pressure washer from Northern Tool, 5HP 230v 30a electric motor


Unlike cheap electric pressure washers that turn off when the trigger is released, this one keeps running much like a gas unit, relying on a temperature bypass relief valve to dump water when it gets too hot from recirculating through the pump which takes about 2 min from all accounts.

I would like to add a flow switch on the high pressure outlet of the pump like this model from General Pumps


To minimize wear and tear on the motor and pump from quick cycling (releasing the trigger momentarily for safety, change position, etc for a few seconds) I would like to add an adjustable relay timer to keep the motor running for say 15 seconds after the trigger is released to give some margin of convenience to allow continued use without shutting down and promptly restarting the motor.

Any thoughts on such a timer? All of the 230v ones I see out there max out at 10amp - does the rating of the relay and flow switch need to match that of the motor? Is there a better flow switch for the application I should be looking at - maybe a flow switch with an integrated timer function?? Also any thoughts on wiring the solution up to the existing on/off switch and 5 HP Leeson motor?