[Mr B]

Just been using my 21ltr hotbox this morning, and I noticed that 80% or so of the water was coming straight out of the flow switch bypass under my hotbox and there was virtually no pressure at the gun.

Process of elimination proved hotbox was ok, washer was ok, hoses were ok. It had to be the flow switch itself somehow dumping most of the water instead of pushing it along the outlet hose...

Not sure exactly how these things work, is it a case of just replacing the whole thing (£36) or is there another way?! I took it off, no obvious blockage, but the 'wire' that pokes out the back into the junction box was loose. Looked like a thermostat?

This is my model if it helps...

http://www.ebay.co.uk/itm/HOT-BOX-240-WATER-BOILER-15LTRS-MIN-PRESSURE-WASHER-/180518854096?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item2a07c31dd0

[Blast Away]

I had a flow switch jammed the other week with a bit of a o ring, from where I don't know. It kept burning off the gun.

Don't know about your problem though mate, don't know much about them.

[Matt Gibson]

Are you sure its not a safety valve? to stop the boiler getting too much pressure?  I didnt think flow switches had overflow/bypasses on them?

[Kenny83]

It will be your safety valve mate, unless the flow switch is leaking through damage, or a loose connection, flow swtiches are flow through components, they don't have any dumping system on them mate