22mm hot for my bath...

[JonHeath]

Hi,

I'm re-fitting my bathroom. I have a 22mm hot feed from the tank in the loft for the bath.

I have a thermostatic valve for the bath (a bath filler waterfall system that goes on the wall). The connections into this for the hot and cold are 1/2" BSP with a 1/2" BSP output.

Will this slow down the flow from the hot, or should it be OK? Presumably I'll need to convert from 22mm to 15mm and then to 1/2" BSP just before the valve, as I'm struggling to find a 22mm to 1/2" BSP male direct adaptor.

I assume it's still worth running the hot in 22mm even though it'll get converted down at the valve?

Thanks
Jon

 

[steve32]

You will need to convert to un-vented or a pumped system for it to work.

 

[JonHeath]

Thanks for the reply Steve.

If I used a pump, would both the hot and cold need to be pumped, or can I just pump the hot?

Also if the valve inputs are in 1/2" BSP do I just run 15mm hot and cold feeds to the valve and not bother with 22mm for the hot? (assuming I pump it)

 

[Roger928]

Connect it up and see how it works.
What the minimum operating pressure? Probably about 0.5 bar.

 

[JonHeath]

Min dynamic pressure 0.2 bar according to the manual. So you're saying try it without a pump?

I actually already have a pump in the loft for the ensuite shower so tapping into that supply for the bath would be fine, and it might well work better off the pump anyway?

 

[Roger928]

What head height do you have?

 

[JonHeath]

Tank and pump are on loft floor which will be around 2m higher than where this valve is going in the bathroom.

 

[Roger928]

That's what I have. But I have a sensible low head gravity compatible bath filler.
I think its pump or unvented for you.

 

[JonHeath]

I think I'll T my existing pump for the ensuite shower and run a feed from there.

I still have a couple of questions on that:

1. Do I need to run a pumped feed for just the hot to the valve or the cold as well?

2. 22mm feed or is 15mm ok? The valve entries are 1/2" BSP.

Cheers

 

[Roger928]

15mm is all you need and both hot and cold should be pumped.