Brass garden hose connectors

On Sun, 12 Aug 2007 16:32:28 +0100, Ben Willcox mused:

Never had a problem using the stop connectors on any of my pressure washers. I have had problems with using brass hose connectors on the crappy plastic ones on the pressure washer though.

I did have a problem with another device, not one with a pump. The length of the Screwfix male brass fitting was fractionally too short to open the shut-off valve in the Hozelock female fitting. I fixed it by soldering a washer to the end of the brass fitting to increase its length

I have since

However hard the pump sucks, it won't be able to put more than 1 bar (15 psi, one atmosphere) of pressure across the stop valve (in addition to whatever the water supply pressure is).

The problem only occurs when the machine is used to suck water in. The stop conector either stops or severly restricts the water flow. On mains pressure feed it won't cause a problem.

Is the fixed inlet pipe rigid or flexible? Prossibly caused by the by pass valve allowing pressurised water back into the inlet. Stop connectors are bad news on pressure washers.

It's rigid, here's a pic of the old one:

Ben.

A flexible hose probably wouldn't have split.

I'm not sure either to be honest, but I have plenty of experience of the problem (30 odd years in the pressure washer game). I think its down to 'play' since these couplings aren't built to exact tolerances. The suction from the pump can be pretty powerful and although the coupling may not stop the water supply entirely it could certainly restrict it.

It can if the machine is sucking water instead of getting it from a pressurised feed like a tap.

Commercial machines can easily collapse a 22mm braided supply hose if the supply is turned off.

No it can't.. just try sucking water up onto the fourth floor and you will see.

Supply pipes aren't designed to cope with a vacuum.. you need a more rigid pipe if you want to suck.