Help Needed for kitchen bathroom renovation

[MarkAtHome]

We are in the process of renovating a kitchen and bathroom and want to replace the majority of water plumbing. Current pipework is ancient, mainly done with compression fittings. New central heating was installed about 8 years ago but was joines to old pipework. Hot pipe runs in 15mm from boiler then enlarged to 22mm after about 0.5m to bath reducing tee to bath hot bath tap in 22mm then 15mm from tee to basin them down into kitchen to tee for washing machine then elbow to kitchen sink.

Cold water returns from supply by kitchen sink in 15mm tee to sink, tee to washing machine, tee to outside tap, then up to bathroomm tee to toilet, then basin, then bathen then to combi boiler.

Boiler is vailiant condensing with warm start.

What size should i replace pipe with or should i stick with current arrangement only addition would be a cold tee after bath for electric shower. Planning to replumb in JG plastic.

Any help or advice much appreciated.

 

[justlead1]

Hi. As you say, the combi was fitted and cistern / cylinder removed. The 15 mm hot just stabbed in to a local hot supply (rather than striping out 22 mm) 15 mm is the standard for that type of system. Good Luck

 

[garyplumb]

I would try and get as much 22mm from your main to the last tee before your boiler, this will increase your flow when you use more than one thing

 

[JCplumb]

15mm's fine for hot from a combi, if you use 22mm you waste gas heating up all that extra water so that it can just cool back down again in the pipe.
It used to be better to run in 22mm from a gravity fed water tank, it's not the case now though.

 

[AWheating]

i agree with gary that it may be a good idea to run some 22mm on the cold. Or run a seperate cold to the boiler and make it your first tee after the stop tap.Normally you would not do this unless its a new build or your gutting and replacing everything.