Three port or Two port valve ?

[Philpoy]

Hi

Wonder if someone could clarify something.

I currently have a conventional boiler which I'm planning on changing to a sealed system boiler.
With my current system i have a three way motorised valve in the airing cupboard.
I have had a couple of plumbers out to quote on the job.
One said the current three way valve will need to be replaced with a two port type as the three way valve will not be needed with the sealed system.
The other guy said that i will need to keep the existing three way valve.

Who's right? Or are both right?

Any help would be much appreciated.

 

[twgas]

If the existing system works the 3 port you've got will be fine, unless you're having an unvented cylinder, which has to have a spring return 2 port valve.

 

[Philpoy]

Hi Mick

Thanks for the reply

Errr what do you mean by an 'unvented cylinder'
Is that revering to the hot water cylinder in the airing cupboard?
Sorry i'm not that clever with heating systems

 

[Gasinayr]

I think you plumbers are referring to the wiring for the new boilers. Some boilers controls are 24v therefore two port valves would be required. if boiler is 240v controls then the three port will be ok

 

[Philpoy]

The new boiler will be a Vaillant Ecotec plus 15.
Not having anything else replaced like the airing cupboard hot water tank.

 

[twgas]

The low voltage stuff is usually on combis, with which you would not, normally, have motorised valves.
Switched lives in boilers are mains voltage.

 

[Philpoy]

Sounds like the three port should be fine then.

Mick, found out what an 'unvented cylinder' is and mines an open vented type and it's not being replaced.

Cheers