Adding a Shower?

[adam81]

Hi,

I want to add a shower into my downstairs cloakroom. Presently I have a storage tank for the hot water in the house and mains cold supply. The image shows my system as it stands, and the proposed shower extension.

At present the whole system bar the HW bath tap (22mm) runs in 15mm. Can I simply extend the hot and cold feed in the cloakroom to include the shower?

Should I go to a combi boiler in the future will the same shower still be adequate or should I be more careful when picking the shower I choose? It is likely the upstairs shower will always be electric, but could in theory this be replaced by a mixer shower as well?

Any help/corrections would be most appreciated?

Cheers
Adam

 

[Hugh Jaleak]

Ideally a mixer shower needs independant feeds from stored water, teeing off existing feeds could cause a problem if water is drawn off elsewhere.

Most combi's will struggle to provide for two drawoff's at the same time, and running more than one outlet at a time from a combi will also depend on the mains supply into the house.

 

[calorific]

The problem that you are likely to have is that (according to your diagram and description) your cold water supply to the shower will be mains whereas your hot water is gravity fed.

You can either go for an electric shower downstairs, or a venturi mixer (google this)

 

[adam81]

Ideally a mixer shower needs independant feeds from stored water, teeing off existing feeds could cause a problem if water is drawn off elsewhere.

In order to achieve this then do I need two independant feeds off the tank, or simply another 15mm tee from the 22mm before it tees for the downstairs WC and basin?

 

[adam81]

The problem that you are likely to have is that (according to your diagram and description) your cold water supply to the shower will be mains whereas your hot water is gravity fed.

You can either go for an electric shower downstairs, or a venturi mixer (google this)

Ah, yeah it is definitely mains cold water I've checked the pipes again. Straight across to the downstairs, then up to the bathroom and from there up to the header tank on 15mm with a 22mm return to the tank.

Looking at the Trevi system I'd need to run 22mm pipe off the tank before it tee's for the elsewhere, and run this down the into the bathroom, not ideal, but doable. It would still tee off the 22mm supply pipe but be the first branch off the system.

Quick google shows I can get one of these, which would reduce it to the lowest pressure which would obviously be the HW.

http://www.plumbworld.co.uk/pressure-equalising-valve-344-20563

Reviews seem favourable and they I could use a standard mixer shower I assume?

At present my header tank is around 4-5m (without climbing in the loft to measure accurately. above the head of the shower should that make a big difference, as the Trevi says it works with headers on the same or 3m heads?

 

[adam81]

I could tee off the cold return and get a gravity fed cold, and tee of the hot for a true gravity fed system.

Was thinking I could put a washing machine fit on the pipes so I can test with a pressure guage