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The Medway Handyman[_3_]

wrote:
Help!!
I have a problem with my RE108 pressure washer. On initial use, it
will work as expected. When the trigger is released the motor switches
off as expected. When trigger is pulled again water will come out of
the lance at mains pressure but motor will not restart.

Not familiar with that particular model, but 30 years in the pressure washer
game....

The unit has been at the local dealers for over a week and they cannot
replicate the problem. They suggested that the 'waterstop' connector
I used may be at fault.

'Waterstop' connectors do cause problems with pressure washers because the
valve is 'sucked' shut by the pump, reducing the water supply, but they
shouldn't cause that particular problem.

I have now tried with different straight
through connectors and, indeed, different shorter hose on the mains
supply. The problem still persists although I have found that by
nearly closing the tap to which the (various) hoses are connected will
allow the motor to restart when the trigger is pulled but then after a
few seconds the flow is clearly restricted that the washer seems to
be 'hunting' for more water.

It would, the machine needs at least 440 l/hr, any less & it will 'hunt'.
Any more water isn't a problem.

It seems to me that the pressure (or is it flow) switch is rather too
sensitive. I believe this is adjustable but do not know where to
start!

It will almost certainly be a pressure switch. Flow switches are rare.
Been trying to find a parts list online with no success. Don't spose you
have one?

Pressure switches on HPC's are very basic things. Basically a piston &
spring. When the trigger is shut the piston is pushed up (or down, or
sideways, whatever) by the increase in pressure and the end of it touches a
microswitch which breaks the circuit to the contactor running the motor.

When the trigger is opened the pressure drops and the spring returns the
piston, allowing the microswitch to 'make' again & the motor re starts.

Sounds like the piston is sticking in the 'up' position & the spring isn't
making it return. When you starve the machine of water its returning as it
should.

Take the cover off & you should see something on the pump head with a cable
going to the electrics box. That will be the pressure switch. Possibly
damaged/weakened spring. Most have adjustments, but don't go mad, a slight
adjustment will have a big effect.

Any adjustment that affects the 'on' pressure will also affect the 'off'
pressure.

Incoming filter is clean - and has been all along.

Good!

Our mains water is supplied through a relatively new but longish
service pipe (about 300 m) which we installed a couple of years ago to
help improve flow rates. The local pressure, prior to installation,
was approx 7bar according to water supply company and the flow was
considered 'acceptable'. The flow has been increased significantly
since we installed the new non-shared service pipe. Hence, I have no
real concerns about the mains supply being in any way unusual.

Incoming water pressure doesn't really matter, only the flow 440 l/hr is
7.3 l/min - time it with a graduated bucket if you want to check.

--
Dave - The Medway Handyman
www.medwayhandyman.co.uk