motorised valve problem

[007agent]

Our hot water/central heating system timer has failed so we have been putting it on manually. Now the pump is not working at all. We have replaced the pump and now that's okay but still have no hot water or heating. The problem seems to be with the motorized valve. We have removed the top cover and when we push the spring inside to the valve with a screwdriver it starts to work but immediately we let go then it goes off. Does anyone have any idea how we can fix this. Appreciate any helpful comments. Many thanks FYI its a honeywell model V4043H1056

[The Builder]

I was just wondering how you were operating the system manually, if the programmer is faulty.
Isn't the programmer built-in to the boiler?

[007agent]

Instead of using the timer, we used the on/off button. This worked until we changed the pump. Now the pump is working, some of the pipes are hot but although all the lights on the controls are on, the radiators are cold and we are not getting hot water. When we turn on the heating the pump starts, but when we turn on the hot water alone, the pump doesn't start. That's why we think its the motorized valve, because when we push the spring on the valve, then the pump will start

[AlBags]

This 22mm two-port motorised valve ... orange wire fires the boiler. This goes live once valve opens.
If microswitch fails the valve motors but nothing happens. New head or preferably drain down and complete valve.
If central heating is calling for heat, white goes live and valve motors .. orange then goes live and files boiler.
Is there another two port valve for HW? That would make the system S-plan. If not, it's probably HW priority.
Is there a cylinder stat fitted? Check wiring/setting on that, and if calling for heat would also fire boiler.
You will have to explain EXACTLY what there is in system and type of programmer to get more help.

[AlBags]

PS .. The over-ride lever is there in case of motor/microswitch failure. As you see, it can be manually moved and 'hooked' over the open gate in the body.