Whole house pump issues

[ChrisR]

Cust has a 5.5 bar Grundfos.
Generally it's a very good quality installation, so I'm wondering if there are aspects where the installer had some information /experience I don't...:
Its supply has a 1 1/2" flappy type NRV, which is letting by, causing predictable problems the Grundfos man couldn't identify!
ANyone know of a reason to use the flappy ones and not a single or double conventional CV?

ALso it's hard-plumbed in copper, which is odd because there's a very expensive variety of flexible connection to the EV.
Again - any reasons?

 

[Agile]

Presumably this is a potable cold water supply?

Isn't 5.5 Bar rather too high a pressure for a cold supply?

I would be more happy to see anything at that pressure piped in copper!

Tony

 

[Biggles..]

Which pump or pump set is it.

check valve that size would normally be spring.but that shouldnt really make any difference.

 

[doitall]

A flapper NRV is unsuitable for potable water, they are designed for heating systems, usually gravity.

Are you certain it's the flapper type and not the Boss brand sprung load single check valve, a pic would be good.

What are the predictable problems

It's quite normal to use flexible connections for the EV, is there also flexible bellows either side of the pump.

What model pump is it.

Is it operating at the full 5.5 bar, hot and cold.

 

[ChrisR]

A flapper NRV is unsuitable for potable water, they are designed for heating systems, usually gravity.

WHyzthat? I didn't think I'd seen one on CW, but couldn't think of a reason why not.

Are you certain it's the flapper type and not the Boss brand sprung load single check valve, a pic would be good.
No - you might be right. It was a boss. Have pics somewhere.

What are the predictable problems
When the pressure switch turns the pump off, the pressurised water goes back through the pump and nrv into the break tank, which overflows, and the pump turns on again cos the pressure's dropped - every half minute...

It's quite normal to use flexible connections for the EV,
Sure

is there also flexible bellows either side of the pump.
NO! And it's sitting on wood.

What model pump is it.
Grundfos CHI 4-60 Prod 4J512106
http://net.grundfos.com/Appl/WebCAP...Row=0&fileid=QU1RIE1RU1BNQUlOICAgIEm8I1Ev7SVR

Is it operating at the full 5.5 bar, hot and cold
Yep, up to 5.5, back to 4.5, up to 5.5, ................
Then into Megaflow prv etc.


Grundfos has to be the worst website on the planet. Masses of carp stopping you getting where you need...

This might work
http://www.grundfos.co.uk/web/HOMEUK.NSF/Webopslag/DMAR-5UTL7K

 

[doitall]

A. They would rattle like you wouldn't believe with the turbulence from mains water.

B. They only work in the vertical orientation.

C. They are not an approved potable water fitting.

The boss valve is likely to be the problem and not seating properly. is it on the flow or feed, I assume the feed, and there's a bit of muck stuck in the seating.

Positive, they make hoses for the purpose.

 

[ChrisR]

valve is likely to be the problem and not seating properly

Yes that's what I said in the first post.

So, have you found the Boss things OK?? Had any fail?

 

[doitall]

Never used them on domestic water Chris, I don't think the spring is that strong, or put another way it wouldn't be my first choice for what it's being used for. But saying that I thought the Grundfoss had built in check valves.

They are cheap as chips though.

 

[glasgowgas]

have a look at a Geestra NRV

 

[doitall]

Or Reliance.

http://www.advancedwater.co.uk/public/Advanced_Water_A4_V5.pdf