15mm first fixing a house run off a combi

[Riley26]

So running the cold in 22mm will give better flow to the boiler and taps/ showers if washing machine and toilets are runing

 

[Terry lambert]

Yep

 

[Riley26]

Thanks and as said hot in 15mm as this is what it comes off the boiler in.

 

[Terry lambert]

Yes

 

[Riley26]

I ran 22mm cold from mains to the combi, combi is near were cold mains enters the building and kept the cold in 22mm till after it has feed the kitchen and the first two bathroom. It then reduces to 15mm to feed one more bathroom and cloak room toilet and basin. Hot is all in 15mm as this is what the combi outley is. Tiny bit concerned that having some of the cold first fix in 22mm and the hot in 15 (limited to this by the combi outlet). Will give different pressures on the hot and cold as the larger 22mm pipe will reduce the pressure though will increase the flow. Or is the effect of this negligible?

 

[nortonj]

Dont worry about it, it will be fine

 

[TCCHeating]

Your logic is wrong Riley

 

[Aquaheat]

Are we going to have another flow rate V's pressure debate again! lol

Still amazes me that there are guys that don't understand it.

 

[Riley26]

Thanks I just wanted to make sure it should be out. Just studying system design at the moment with my level 3