2 port wiring question

[EvilDrPorkChop]

correct as most dont have any sat ports on your unvented cylinder stat so you cant control them like that

thats why they always recommend to upgrade to an s plan

you could install a 28mm port valve and use the white wire as satisfied eg powered when closed

Every unvented cylinder stat I’ve come across has a satisfied port. Even on the Megaflo/OSO inbuilt stats do.

The way your suggesting to me wouldn’t meet any energy efficiency regs at all. As the boiler could be firing with no demand needed from the cylinder.

I do agree though trying to use a 3 port with a 2 port is daft. It’s better to convert to a S plan system.

 

[ShaunCorbs]

Every unvented cylinder stat I’ve come across has a satisfied port. Even on the Megaflo/OSO inbuilt stats do.

The way your suggesting to me wouldn’t meet any energy efficiency regs at all. As the boiler could be firing with no demand needed from the cylinder.

I do agree though trying to use a 3 port with a 2 port is daft. It’s better to convert to a S plan system.

last mega flow and gledhill 300-400l didnt the stats had no ports (as any stat does) but not wired up

havent fitted an oso so cant comment

 

[wattsie1987]

Normally open 2 port powered closed from cylinder stat sat or hw off on prog?

 

[EvilDrPorkChop]

Here's the diagram you need.