Unvented cylinder thoughts

[Danv44444]

Hi guys I'm currently first fixing a loft conversion with 3 showers and 1 bath and about 5 basins. I was wondering whether to take the colds apart from the kitchen sink off of the balanced valve on the multi bloc or just put a 22mm prv on the cold main and then tee off the cold and not come off the balanced port?

Any thoughts please?

 

[chris watkins]

How high is the loft up above the ground ?
Whats the static pressure at peek times ?
Whats the flow rate & the likely usage of the fittings is it just a domestic house ?
Size of incoming supply?

or take off the rising main all the fittings you can that do not connect to a mixer / blending fitting, so kitchen, utility & machines, cloak room, any other WCs etc you can. So you just do showers / mixers on the balanced port.

 

[Danv44444]

Thanks Chris it's a 15mm supply currently but I've ran the main cold supply in 22mm with a view to having a new main put in in the future.
The trouble is I'm not totally sure what taps the customer is having yet. Obviously the wcs won't be mixed and washing machines etc. The loft height is 3m max above the ground floor. The cylinder is going upstairs about 3m higher than the lowest point

 

[Danv44444]

As for flow rate it shoots water all over my flow cup

 

[Danv44444]

Standing pressures about 4bar

 

[chris watkins]

(I think you know a 15mm main is not going to supply all that new lot satisfactory hope your customer is aware of that)

So cylinder is one floor above the point where the standing pressure was measured at 4bar, taking that you install the PRV close to the top of the cylinder the pressure available at it would be around 3.55 bar ? (4bar = 40Metres - 3M one storey - height of PRV off of the floor 1.5M = 35.5Metres) PRV set 3Bar I take it, so not a lot to be gained running up & down throughout valve more important to take of what you can as you go up I would have thought.

but it is not going to be that great first thing in the morning in that loft en-suit shower with a couple of toilets flushing below, pound to a penny.

 

[Danv44444]

Cheers Chris thanks for your time. I will take of the cold main for utility and kitchen and the bath. Then do the rest of the balanced connection. The bath is going in back to back with the cylinder so I'll just tee in the cold before the balanced valve.