38Kw EcoTec 22mm or 28mm F/R?

[zaceverett]

I'm moving over to a sealed system on my EcoTec 38kw boiler. The old flow and return were in 28mm which was there long before the Vailant was installed.

I'm running 10 rads with a small UFH circuit and unvented cylinder.

Could i get away with replacing the 28mm to 22mm instead on the 'backbone'.

The boiler itself has 22mm connections and the pump will be 5m away from the boiler so not a long travel. IT will be connected to an s plan plus.

I've read differnet replies previously about matching the boiler output to pipesize but given the extra cost of 28mm just wondered if 22mm would suffice?

 

[Deleted member 120897]

22mm should be fine, if it needed any more and the connections would be larger. 38Kw seems overkill for what you require.

 

[Last Plumber]

22mm (Copper) will do up to around 55.000 - 60,000 Btu (16 -17.5 Kw) on a sealed system in my book. I personally wouldn't go above that and less on an open vented.
Why have you got a 38Kw boiler?

 

[zaceverett]

22mm (Copper) will do up to around 55.000 - 60,000 Btu (16 -17.5 Kw) on a sealed system in my book. I personally wouldn't go above that and less on an open vented.
Why have you got a 38Kw boiler?

Not sure why we ended up with a 38kw boiler, that's what the plumber spec'd when we had to replace our really old boiler and move it to another room.
I'm not sure that it was plumbed in correctly as in previous posts to this forum i had the question why my return to the boiler actually got very hot a lot quicker than the feed. I've got try and trace it down but suggestions are may be the pipes were crossed and it's been working with the pump on return.

Thanks for your help I'm going to look at replacing the 28mm with 22mm when i move the pump to a airing cupboard. Looking at a wilo yonos PICO 25/1-6-130.