Combi vs tank - which should I go for?

[b21playa]

Just fit the combo valve eg prv at your mains stop tap or a secondary pressure reducer to keep the whole system at the same pressure

First thing to do is get a heat loss done then you know the load of the new boiler

Hi Shaun

I’ve got a new mains being fitted beginning of March. I’ve asked for 32mm which will terminate in the garage. I’ll do a temp connection to the existing in 22mm pex which I already have but ultimately it needs to feed to cupboard where new tank will be. This will need to run under the floorboards, can this be done in 28mm pex/pb pipe?

Many thanks

 

[ShaunCorbs]

Yes as your running plastic it’s best to upsize like you’ve done eg 22mm copper 28mm plastic / pex

 

[b21playa]

Yes as your running plastic it’s best to upsize like you’ve done eg 22mm copper 28mm plastic / pex

That’s great.

Water main guy recommended 25mm so as not to reduce pressure but as prv is 3bar I thought it was ok to move to 32mm
I had read 28mm has the same internal diameter as 32mm mdpe so thought best to run this all the way to the prv location. Just need to decide on pex or polybutylene pipe.

The 28mm plastic will terminate to a stopcock and then run internally for a short distance in 22mm copper to the prv

 

[ShaunCorbs]

Yes fine to move upto 32mm

Yes 28mm copper is same dia internally as 32mm alk