Service valves - what is the point?

[scubapete]

Ok, excuse my ignorance and bear with me..

I have a low pressure system and am about to re-plumb my bathroom (which contains no service valves) and have learnt that pipe bore is everything to make sure there's a decent amount of water coming through.

There is currently a 22mm feed for hot and I have run a new 22mm pipe from CWC for cold to make sure there's a balanced supply to the basin monoblock.

All the pipework runs on the floor next to the skirting board and will be hidden by furniture.

Why should I fork out for 4 expensive full-bore service valves? Currently I close the full bore level valve between CWC and HWC and open the hot water taps to equalise the water level. I even do it in the kitchen to make sure the water level is below the bathroom and therfore no chance of a leak.

I mean realistically how often are you going to use the service valves? I feel like I'm missing something really obvious here.

 

[scubapete]

ps I realise I need one for the dedicated CWC feed as there's no way of draining away the water.

 

[kevplumb]

what is a CWC

 

[scubapete]

Apologies, thought that was aaccepted abbreviation for the cold water cistern in the loft.

 

[Agile]

Do you realise that its usual to use 15 mm to feed 1/2" taps and 22 mm to feed 3/4" taps?

Tony

 

[scubapete]

No, I did not.

But, as I say the existing hot feed is 22mm supplying a 1/2" basin and 3/4" bath tap.

The existing cold feed to basin (and bath) is 15mm mains which completely overpowers the hot.

I wanted to make sure the basin has completely balanced supplies meaning 22mm feeds and reducing couplers to 15mm at the last possible moment.

 

[Agile]

You will never get balanced supplies whateve pipe sizes you use if cold is mains and hot cistern fed.

There is a pressure ratio of about 20:1

Tony