Replacing 28mm copper H/W flow & return with 22mm copper? (or even 22mm pushfit?)

[F1_wired]

I need to re-route 28mm copper pipe, in our bathroom, which is the flow & return for the hot water cylinder heat exchanger coil. A new boiler was fitted couple of years ago and was converted to a fully pumped system at the same time.

My question is, can I use 22mm pipe for the re-route, (approx 1.5M section) now that H/W is pumped and not gravity fed? Could I even use plastic push fit?

I assume that when I do this, closing the supply from the f&e tank and draining down the C/H through the lowest rad will also drain the H/W flow & return circuit ....

 

[denso13]

Yes to everything. 28mm was typical for gravity systems, as you say.

 

[ianmcd]

yes not a problem

 

[rules&rulers]

Well maybe,can your boiler/is your boiler designed to operate on 22mm.

A few photos will confirm,

 

[Madrab]

If you have a hot water cylinder and a Y/S plan then move your motorised valves to manual during the drain and refill.

Shut down as many of your rad valves as possible to retain as much water with its inhibitor that will also reduce the amount of rusting that would occur if rads were emptied.