how to change head of plumbcenter 2-port zone-valve

[bobalicious]

hi,

I think the plumbcenter part 340075 2-port zone-valve is busted.
I removed the casing to move the head and couldn't see any easy way to remove the head from the brass fixtures.

Plumbcenter assured me that it was just a honeywell valve with a plumbcenter box.
Also, they said that they use to have a document explaining how to remove it but its no longer availlable.

This all suggests
1) the head is replaceable with a honeywell head.
2) its not as easy as unscrewing two-diagonal screws

if anyone know how to remove this valve then please enlighten me.

My reasoning for why I want to replace the head.
1) when I open the valve manually (push tick and lock into MAN) the valve opens but the boiler does not fire.
2) whilst I turned the room-thermostat on and off someone confirmed that 240v was seen at connections between Switched-Live and Neutral into junction-box that feeds valve.

I've been trying to figure out how the whole system has been connected and its a bit of nightmare as always to understand someone else's thinking.

I think I have an S-plan with an oil-boiler and an indirected-unvented tank.
3-Zone-valves:
Zone1: hot water
Zone2: upstairs rads
Zone3: downstairs underfloor heating.

Let me know if you have any idea how to take these zone-valves apart.

ta,
Bobo

 

[mickyg]

dont think you can remove the head asfaik. you can change the motor.
It is made by honeywell but its not the same as a honeywell.

 

[shorky]

you cannot change these heads, you have to replace the entire valve.

 

[bobalicious]

How can I determine which part within the valve-head is broken.

Should I try stripping it and seeing if it comes apart from the brass ?

As you can imagine I really really dont want to drain the system and replace the whole valve.

There is also an Orkli 22mm 2-port-Zone Valve on the Under-Floor-heating supply.
If I do drain the system to remove the Plumbcenter Zone-valve then is it worth replacing the Orkli Zone valve too ?

FYI, plumbcenter Zone Valve is dated Feb-2008.
Lastly, does anyone have a wiring diagram of
A) how the 2-port zone valve should be wired into the main system
B) An internal Diagram of the PlumbCenter 2-port 22m zone valve (might help dismantle it)

ta,
Bobo.