A mix of 10mm microbore and 15mm

[lsearson]

hi all,

i have a town house (3 storrey)

just getting ready to install my new combi boiler (vaillant). Im running from the boiler in 22mm to a manifold and from the manifold in 15mm, this is on the 2nd and 3rd floors, But here is the question the ground floor, has 22mm to a manifold then microbore 10mm pipe work but has all been concereted into the floor (i know this because next door dug it up).

the pipes downstairs have never caused me a problem, so can i leave it how it is and use it with my 22x15 manifold upstairs, also im planning on fitting trvs on nealt all rads so will this also play a part

thanks in advance for your replys

Regards

 

[gas4you]

Shouldn't be any problem, but you may have to balnce 1st & 2nd floors down on locksheilds

 

[lsearson]

hi

thanks for that, should i bother getting trvs for the 1st and 2nd floors then or shall i just use normal lockshield valves and just trvs on the 3rd floor,

another idea i had was to put full bore isolating valves on the flow and return on the 1st floor just before the manifold and leave them quarter closed, so it wouldnt steal to much pressure from the top two floors, is this worth doing

regards

 

[chrishutt]

Isolating valves of the ball type should only be set fully open or fully closed. In intermediate positions the main seals are by-passed and only the spindle seals then prevent leakage.

 

[Softus]

Is that also true of the Prestex ones Chris?

 

[chrishutt]

I should think so, if they have the same basic construction. It may be that the spindle seal on its own is good enough to provide long term security, but with the main seals by-passed any contaminants in the medium (mainly iron oxides with CH systems) can deposit on all the moving parts of the valve, leading to premature failure.

 

[ChrisR]

The Prestex ones have a "proper" gland seal arrangement (2 triangular section rings iirc) whereas a lot of the cheaper ones just have one O ring. The Plumbcenter ones are OK too and not exorbitant.

I wouldn't use any ball type valve for restricting flow though, they make a racket. Gate valves are quieter, or you could use a radiator valve.

Tall houses always benefit from trv's I reckon , especially if you're a normal human being and leave doors open! They also help with balancing difficulties.