Need advice on tap inlet/outlet size for bath filler please!

[doogyscoot]

Hi all, I have ordered a Grohe Talentofill system for my new bath. This is a system which has an intergrated bath filler and pop-up waste so I just need to get some deck mounted valves to control the flow of water into the filler itself. I need some advice though. The water intlet for the filler is 22mm so what size valves would be used to go before this.
Would I need 1/2" or 3/4" valves? I'm also presuming I just get the valves and a Tee fitting so the hot and cold mix at this junction before they reach the single inlet on the filler?
Have seen a few deck mounted tap/valves I like the look of but want to make sure I don't pick up the wrong ones.
Ta!

 

[Agile]

It all depends on the source of hot water and the current pipe sizes.

I am surprised that you have bought expensive bits without know if they are compatible with your system. Thats why a competent plumber is usually advisable when you are spending a lot of money on top of the range fittings.

Tony

 

[picasso]

what system are you putting your new filler on?

 

[doogyscoot]

Agile, the system was ordered at a greatly reduced cost - £135 including the finishing trim kit, less than any of the other options I was interested in. I will get in touch with my plumber and ask him for his thoughts.

The plumber is yet to take the hot feed off the system for the bath but I believe the cold feed which already exists is a 1/2" pipe.
In terms of the system it is attached to I am assuming you want to know about pipe sizes etc but if you can be more specific I will try and get all the info together. If it helps the hot comes from a combi boiler with a stated flow rate of 9.7 l/min at 35 deg. pressure in the mains water system seems pretty good as we are ground floor of a tennement flat though I have no measurement.

 

[Agile]

OK well you have 15 mm pipe sizes and mains pressure so 15mm is fine.

The flow rate from a basic combi is not very good and will take about 15 min to fill your bath but presumably you already know that.

Tony

 

[doogyscoot]

Thanks Tony, I spoke to my plumber and he has said that for a bath I require 3/4" valves so I'm guessing I just go with that.
I know the combi won't be that great for filling the bath but thats fine. We are looking at getting a new and more effective boiler at some point in the future anyway

 

[Agile]

The bath end may have 3/4" fittings but there is no point in using 22mm pipe if the source is mains pressure from a 15 mm pipe.

Its worse than that because the hot pipe will take longer to get hot water to the bath and fill it with more cold water if its wrongly piped in 22 mm. Amazing that some plumbers dont know that!

Tony

 

[doogyscoot]

Ah, so I should be after 1/2" taps then? Think I was less confused before I asked the plumber
Would I be right in thinking there are 1/2"-3/4" converters anyway? so it wouldn't be the end of the world if I got either? Sorry if this sounds ignorant but plumbing fittings is the one thing I really don't have a great grasp of... most other things I'm fine with. Thanks for the help!

 

[Agile]

Its traditional to plumb a bath supplies in 22 mm so you will have to get 3/4" taps etc.

But the pipework in your case feeding the taps should be in 15 mm.

I would hope your plumber would know this! But some dont!

Tony