Flow through zone valves

[b21playa]

Hi all

Just had a new zone valve delivered and noticed they don't open up much say compared for an isolation valve. Does this not restrict flow?

Many thanks

 

[stem]

Assuming that you are opening it with the manual lever, then most models will only partly open. When they are opened electrically they will fully open.

This is because the manual lever is designed for opening the valve whilst the system is being filled, at the far end of the travel there is a small microswitch that operates the boiler, the manual lever opens the valve but not to the full extent of its travel so that it doesn't operate the microswitch.

To bench test it, it's possible to fit a 13A plug (with a 3A fuse in) to the zone valve lead L,N & E and plug it in. You will then see how far it opens and you will hear a 'click' from the microswitch.

 

[b21playa]

Assuming that you are opening it with the manual lever, then most models will only partly open. When they are opened electrically they will fully open.

This is because the manual lever is designed for opening the valve whist the system is being filled, at the far end of the travel there is a small microswitch that operates the boiler the manual lever opens the valve but not to the full extent of its travel so that it doesn't operate the microswitch.

To bench test it, it's possible to fit a 13A plug (with a 3A fuse in) to the zone valve lead L,N & E and plug it in. You will then see how far it opens and you will hear a 'click' from the microswitch.

thanks for this, makes sense and explains it perfectly