Bath supply

[melkor12]

Question: the original bath cold water supply (mains pressure) is 22mm but the hot water supply is 15mm should both be 15mm or both 22mm If not why not - balance/flow issues

I have a Vokera combi boiler.

I'm intending to fit a "Hudson" type thermostatic valve (wall mounted) to supply a bath Centrafill and ceiling mounted "rain-shower".

I am planning to use PEX pipes for the run from the valve to the outlets.

The valve requires 3/4" x 22mm or 3/4" x 15mm outlet adapters for connection to the pipe run.

Grateful for advice.

Ron

 

[Bahco]

You will probably have to change the cold to 15 mm to fit your shower inlets. Cold should not really be 22 on a combi system but do check its not a tank supply.

 

[ChrisR]

"rain-shower".

Check the flow rate it needs against whatever your combi can deliver.
Usually combis would have to be 35kW minimum for big roses.

 

[melkor12]

Thanks for response Guys.

(1) There is no tank;

(2) The Vokera combi (Excell 80SP) has a 23.7kw max heating output. The thermostatic valves specifications confirm that it is (a) suitable for unequal pressure; (b) minimum of 1 bar and maximum of 5 bar pressure operation and (c) suitable for either combi or tank fed supplies;

(3) My concern is whether 22mm connection from the thermostatic (3-way) valve to the Centra-fill only is correct or as suggested all the outlet runs should be 15mm

(4) At present the H & C pipes from the floor (original bath tap lines) are terminated by 15mm and 22mm isolating valves - can I simply attach a reducer to the 22mm isolating valve and therefore have 15mm (PEX) pipe runs to both the rain shower and the bath Centra fill via the thermostatic valves outlets

Ron