Self suction and Pressure washers - an explanation.
Some pressure washers are good at drawing their own water from a water tank,
bowser or even swimming pool or pond water others aren't.
The main reason for this is the speed of the motor and therefor the speed at
which the pump runs. Electric motors are either high speed brush motors
(only used on domestic rated machine) or induction motors. In the UK 240v induction motors
spin at either 2800 rpm or 1400 rpm, the slower motor is better.
Pumps that run at 2800 rpm do not work very efficiently
on suction
Pumps that run at 1400 rpm are much better at sucking in their own
water.
Indeed Kranzle Pressure Washers that run at 1400 rpm are self priming and will lift water from a depth of just over 7 feet (2.5m). This is because the bore of the plungers or pistons is larger and the inlet and out let valves open and close at half the speed of a 2800rpm pump/motor. In fact because the Kranzle valve casing is made out of brass, the plungers are ceramic coated and the valves and unloader are made from stainless steel our pumps can even use sea water, we just recommend that the pump be rinsed out with clean water after use so that salt does not dry in the valves.
Kranzle pumps that run at 2800 rpm will work on suction but not very well and, as with all 2800 rpm pumps, if used like this for long periods or if the suction height or distance is too long damage will occur.
We strongly recommend that you buy a pressure washer with a 1400 rpm motor if you intend using it on suction rather than from a tap. Also note that if you need to run your pressure washer a long distance from your tap or you sometimes have low water pressure or you will be using your pressure washer in many different locations it is not always possible to ensure that you will have an adequate water supply for your pump. Again in this case you should buy a machine that runs at 1400 rpm so that you have the choice of running it from a small tank with a hose running into it, this acts as a buffer and will protect the pump from water starvation.
If you have any doubts or want more information on choosing the right machine please email us or during office hours call our local rate number 0845 053 9107 from within the UK.
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