Anyone know what would happen if I use my Karcher presuure washer
without fitting a non-return valve to the tap end?

In an earlier contribution to this discussion,
wrote:

Anyone know what would happen if I use my Karcher presuure washer
without fitting a non-return valve to the tap end?

Not a lot! What are you expecting to happen?

I think that, legally, you're supposed to use a double check valve when
using hosepipes etc. outside to avoid any danger of dirty water getting
sucked into the mains system in the event of a mains failure. I would have
thought that the risk of that was negligible when using a pressure washer.
--
Cheers,
Roger
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On 31 Dec, 15:21, "Roger Mills" wrote:
In an earlier contribution to this discussion,

*wrote:
Anyone know what would happen if I use my Karcher presuure washer
without fitting a non-return valve to the tap end?

Not a lot! What are you expecting to happen?

I think that, legally, you're supposed to use a double check valve when
using hosepipes etc. outside to avoid any danger of dirty water getting
sucked into the mains system in the event of a mains failure. I would have
thought that the risk of that was negligible when using a pressure washer.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Thanks for that - I wasn't expecting a lot to happen, but as it is
mentioned in the instruction book, and I couldn't find one locally,
thought I'd see if I could get someone knowledgeable to advise.

Thanks

Graham

On Dec 31, 4:21 pm, "Roger Mills" wrote:
In an earlier contribution to this discussion,

wrote:
Anyone know what would happen if I use my Karcher presuure washer
without fitting a non-return valve to the tap end?

Not a lot! What are you expecting to happen?

I think that, legally, you're supposed to use a double check valve when
using hosepipes etc. outside to avoid any danger of dirty water getting
sucked into the mains system in the event of a mains failure. I would have
thought that the risk of that was negligible when using a pressure washer.

Not so much a mains failure, as the gentlemen in large red trucks
turning on their pumps. A hose filling up a swimming pool or a pond
can easily suck the water back into the mains unless a non-return
valve is fitted. This is less of an issue with a pressure washer
because the end is usually not dipped under water.

Martin Bonner wrote:
On Dec 31, 4:21 pm, "Roger Mills" wrote:
In an earlier contribution to this discussion,

wrote:
Anyone know what would happen if I use my Karcher presuure washer
without fitting a non-return valve to the tap end?

Not a lot! What are you expecting to happen?

I think that, legally, you're supposed to use a double check valve
when using hosepipes etc. outside to avoid any danger of dirty water
getting sucked into the mains system in the event of a mains
failure. I would have thought that the risk of that was negligible
when using a pressure washer.

Yup, its just to comply with the water board regs.

Not so much a mains failure, as the gentlemen in large red trucks
turning on their pumps. A hose filling up a swimming pool or a pond
can easily suck the water back into the mains unless a non-return
valve is fitted. This is less of an issue with a pressure washer
because the end is usually not dipped under water.

Plus a set of inlet & outlet valves! Back siphonage virtually impossible.

A water authority plonker once told me, after admitting that back siphonage
was about as likely as a lightning strike, that if the water main were shut
off, the suction from the pressure washer could cause a 6" plastic water
main to collapse.

He didn't specify what size pressure washer might be able to do this - I
reckon about 500hp :-)


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

On 31 Dec, 17:26, "The Medway Handyman"

A water authority plonker once told me, after admitting that back siphonage
was about as likely as a lightning strike, that if the water main were shut
off, the suction from the pressure washer could cause a 6" plastic water
main to collapse.

He's talking crap anyway - thickwalled plastic water main (and yellow
gas pipe) makes a perfectly fine vacuum chamber, if you put a suitable
domed end cap onto it. You might suck a flat plate endcap inside out,
but you won't collapse a _cylinder_ of this material.

Andy Dingley wrote:
On 31 Dec, 17:26, "The Medway Handyman"

A water authority plonker once told me, after admitting that back
siphonage was about as likely as a lightning strike, that if the
water main were shut off, the suction from the pressure washer could
cause a 6" plastic water main to collapse.

He's talking crap anyway - thickwalled plastic water main (and yellow
gas pipe) makes a perfectly fine vacuum chamber, if you put a suitable
domed end cap onto it. You might suck a flat plate endcap inside out,
but you won't collapse a _cylinder_ of this material.

I did try to tell said plonker this...... but he wasn't listening.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257