back pressure from power washer

[wingreen]

I'm using a power washer (fitted to an outside tap). Its causing a lot of back pressure when I switch nozzle on and off and I need something to fit on the outside tap to stop that happening. (I know I need something to stop water getting back into the mains). Its a Nilfisk and Nilfisk say I should use their "BA Valve" - but I'm damned if I can find one for sale and I'm not sure it would stop the back pressure. Is there a (cheap!) alternative "mechanism" I can use. Am I right that a double check valve (fitted "in line" or changing the outside tap for one with built in double check valve) would solve my problem? Thanks

 

[PlumbBobBob]

hi wingreen welcome to the forums. you need to fit a double check valve to the pipework under the sink before the pipework goes out through the wall to the tap. taps that have inbuilt check valves only last for a relatively short time due to freezing temperatures causing the innerds to fail.

 

[Simon F]

Hello wingreen,:iagree:.. but you should have a double check valve fitted anyway irrespective of the use

 

[wingreen]

Thanks to both for such quick replies. I thought putting one inside the house was only a requirement for new installations post 1999? I'd love to put a double check valve under the sink - but you haven't seen my sink! - or more accurately, the plumbing under the sink - the pipes from the stop tap are essentially "chased" into the wall - doing anything there is going to be a nightmare. I take the point about outside ones not lasting long but we don't get much frost up here on Anglesey and, if it came to the crunch, I'd put the "old" tap back on for the winter (Power washer stays in the shed until Spring!). What if I fitted an "in line" double check valve on the "end" of the outside tap? (I could just take that off for the winter).

 

[PlumbBobBob]

you could but it would look ugly 1/2 or 3/4 female straight to 15mm copper, to 3/4 male to 15mm copper, with 3/4 tap connector to hose push fitting. i'll sort some pics.

 

[Simon F]

you can get a hose lock double check valve fitting

www.hozelock.com › Watering › Hose Fittings

Non Return Outdoor Tap Connector: 2181

 

[PlumbBobBob]

thanks simon i go searching for pics to make up a heath robinson contraption and you go and find exactly what the op needs :laugh3:

 

[wingreen]

Again - many thanks. Looks like the ideal "off the shelf" solution. Having said that - I quite like the Heath-Robinson solution!

 

[wingreen]

Mind you - just found the hozelock for £4.99 on ebay, which is very cheap - so will buy and give it a go. (Heath-Robinson - turn in your grave!)