Booster pump on unvented hot water system

[Masood]

Need a little imaginative input here, please - custard has an unvented cylinder on ground floor, and a bathroom in the loft conversion. He had a new mains put in, and pressure both hot and cold are great throughout the house except for the loft bathroom. He would like a booster pump installed, but Stuart Turner are adamant that you mustn't pump out of an unvented cylinder. I can get around not being allowed to boost mains by installing a break tank on the cold, but what to do with the hot? Any ideas? Short of suggesting a small direct cylinder just serving that bathroom, I'm a bit stumped...

PS, I know that you can now buy 12l/min boosters that are legal on cold mains, but that won't really help him...

Thanks,
Masood

 

[chris watkins]

Why can't CW break tank be made to feed both the cold & the cold feed into the un-vented ??
What pressure did you have on the system at the moment (working) ???

 

[Dannypipe]

What is the pressure upstream of the PRV?

 

[Masood]

What is the pressure upstream of the PRV?

I don't know - I was there sorting out some problems with UFH fitted by his builder (who he's in dispute with), and he mentioned this in passing. He had a meeting to get to, and I had to get to another job, so it was just a very quick look and a request to have a think about a solution, no time to get the weir cup & pressure gauge out.

That said, opened hot & cold taps downstairs and on 1st floor bathroom just to get a feel for pressure, and it really is good pressure. Just the new bathroom at the top of the house that's a bit weedy.

Why can't CW break tank be made to feed both the cold & the cold feed into the un-vented ??

That was my first thought, but pressure downstairs is so strong that he may need pressure reducing valves downstairs. He was very reluctant to do this for no reason that I can think of (except maybe cost, but he's seriously loaded and I told him it would be particularly costly) Added bonus of this, of course is that the booster pump is downstairs, and not right next to the bedroom! (Loft bathroom is an ensuite)..

 

[Masood]

I told him it would be particularly costly) ..

Wouldn't be, that should read!

 

[chris watkins]

Won't the existing PRV control the new increased pressure ? How high is the building ?

 

[Gray0689]

If the pressure is good downstairs then on unvented it should be the same everywhere
There has to be a problem on pipe work on top floor

 

[Gray0689]

If the pressure is good downstairs then on unvented it should be the same everywhere
There has to be a problem on pipe work on top floor

Unless its a very very high house witch I doubt

 

[Masood]

Won't the existing PRV control the new increased pressure ? How high is the building ?

3 stories now, including the loft conversion. Normal height house. The existing PRV would cancel the boost, but it can be adjusted up...

 

[Dannypipe]

He'll have around 3bar of pressure if the pressure into the house is above that. The PRV on the cylinder will limit to 3bar as we know. If he doesn't have 3bar + coming in, then you will have to think about a pumped accumalator possibly before the cylinder. The pump just increases the pressure in the accumalator at about 10litre per minute.

If he has 3bar + and isn't getting a good outlet in the loft, I would imagine it might be another issues. For every 10 meters of head, you lose 1 bar. How high is this loft?!

Possibly the pipe work is too small in loft, and it's starved by other outlets? Look at the more basic stuff first. So many times I've started to think outside the box, and then gone, oh it's switched off in the cupboad...etc etc.

 

[Dannypipe]

Gray, always beating me to the punch!!

 

[Masood]

If the pressure is good downstairs then on unvented it should be the same everywhere
There has to be a problem on pipe work on top floor

Yes, quite likely. Everything is now finished, tiled, hardwood floors, and so on. The guy is in dispute with the builder, so this was a little thinking outside the box solution required. It doesn't need a huge boost - the shower works, he'd like a little more than the gentle trickle that he currently gets..

 

[Gray0689]

Sorry Danny

 

[Gray0689]

If its a problem with pipe work then no matter what you do your still likely to have the same problem imho

 

[Masood]

If its a problem with pipe work then no matter what you do your still likely to have the same problem imho

I think you're right, but he absolutely doesn't want any of the decor disturbed... Hey ho, it's still a working shower!

 

[Dannypipe]

Check the obvious things first. It could be a check valve in the shower that's slowing it down. (on hose) Or a flow restrictor (on hose or on rose) seen that before.

Check all the basic stuff out. Might be an easy fix, and a chance to shine!

 

[Gray0689]

Is the bad pressure just on shower what's it like on basin toilet ect

 

[Gray0689]

Lol you was quicker there Danny
We thinking on same lines

 

[Mike Jackson]

Sounds like a walk away job to me. He's already in dispute with the builder, next will be the plumber.

 

[Dannypipe]

Sounds like a walk away job to me. He's already in dispute with the builder, next will be the plumber.

That did cross my mind too. Be careful. Could have a Rogue Customer on your hands.