central heating wiring

[bigfeet84]

hi i have a danfoss fp715si programmer which controles hw or ch
when i have ch on the motorised valve opens but boiler doesnt fire unless you also hit the hw on.

any1 know much about the wiring for these

 

[petit_pablo]

What type of system do you have?

Sound slke the timer has been set up for gravity hot water, is that the case with your system?

 

[bigfeet84]

hi i have a circulating pump so i assume its a pumped system. the programmer is set to pumped. i think it a wiring fault i have live going to dhw on and htg on but nothing going to htg off or dhw off.

also i dont have a room stat

 

[bigfeet84]

Untitled

• bigfeet84
• 24 Oct 2011
• 2

basic diagram of the wiring

my wiring

 

[jackthom]

Untitled

• jackthom
• 19 Dec 2008
• 18

Do you have a motorised valve like this one in the system?

If so it's a common fault for the microswitch inside the top of this valve to become faulty and not switch on the boiler when Heating-Only is required.

 

[bigfeet84]

i think its like that but it only new