What is a check valve - instructions for Trevi Boost

[wolfboy]

I have been reading the instructions for installing a Trevi Boost shower.
It says that it's essential to fit check valves on both hot and cold supplies,
to prevent crossflow. It also says to fit as far upstream as possible.

What does the Check Valve do, are they talking about preventing backflow? And does upstream mean nearer the shower end. (sorry if that's a stupid question)

Thanks

Wolfboy

 

[BoxBasher]

Yes, check valves are to prevent backflow.

Is the wording as far upstream or just upstream? Upstream does mean before the shower.

 

[bster]

yes -backflow protection,

and upstream I would have though as far downstream as possible (closer to the outlet-i.e.shower) nut i may be wrong (i am an apprentice so seek further advice to confirm!)


BTW - they only allow the water to flow in one direction

 

[wolfboy]

the wording is 'as close upstream as possible' so I guess that's under the batth.

Is this the sort of thing?

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=16281&ts=12660

 

[bster]

http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=100121&ts=13542&id=19860

theseb will doit!

 

[ChrisR]

A 22mm one on the HW side might be better - lower resistance. Do use a SINGLE cv though as bster indicated.

 

[Softus]

the wording is 'as close upstream as possible' so I guess that's under the batth.

I'd interpret that as being close to the cylinder and to the rising/incoming main.

Is this the sort of thing?

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=16281&ts=12660

No. You've posted a link to a double check valve of restrictive bore. You need a full bore single check valve.

 

[BoxBasher]

A little ambiguous.

I would interpret as far upstream as possible as being close to source (tank)

But I would interpret as close upstream as possible to mean being close to the shower on the upstream side...

Do the chinese/russian instructions make more sense?

 

[wolfboy]

Thanks for all your, I will check upstream bit with the maufactuer.

Anyone know a way of checking the mains pressure without using a meter, which I assume would mean spliting the pipe work?

 

[Softus]

Anyone know a way of checking the mains pressure without using a meter

You can measure it with a bottle of wine. Simply give the wine to a neighbour and ask them to do it.

...which I assume would mean spliting the pipe work?

You can get adaptors to attach a meter to a garden tap or to a kitchen tap.

 

[wolfboy]

For anyone fitting the Trevi Boost I have checked with the manufacturer and the term
'as close upstream as possible'

means as close to Shower Head as possible.

Now we know. I intend to fit one over next couple of weeks so will let you know how it goes.

 

[wonderb0y]

If both feeds are coming from the tank i wouldn't of thought you would need to use a check valve, unless the preasures were differant, i.e cold direct from mains.

 

[Softus]

If both feeds are coming from the tank...

Do you actually know what a Trevi Boost valve is?

It's a venturi valve, i.e. specifically designed for unbalanced supplies.

 

[wonderb0y]

arhh ok well do as told above then

ive just looked at them now god knows why i havn't looked at em before.