Vaillant Ecotec Plus System Boiler problem.

[soundwave49]

Hi Guys. We have an intermittent problem that when hot water is set to be on say 3 hours and heating set for say 6 hours on the programmer the heating goes off when the hot water goes off after 3 hours and not staying on for the 6 hours! Also, sometimes the heating wont fire up on its own unless i fire up the hot water too! We have two 2 way motorized valves. Any ideas please?

 

[muggles]

Motor in the heating 2 port has become weak and is no longer fully opening the valve

 

[soundwave49]

Thanks, but when I slide lever on valve to manual it still does not fire up!

 

[snb1]

it won't fire up with the lever in manual because that only partially opens the valve and the valve needs to open fully for it activate the microswitch to send the demand for the heating

 

[Johntheo5]

Thanks, but when I slide lever on valve to manual it still does not fire up!

That manual lever is designed to latch open the valve to facilitate refilling after a drain down and will not fire the boiler as pointed out but what you can test to see if its a faulty end switch which fires the boiler when the valve is energized and fully open.
Switch on the CH and ensure the roomstat is calling for heat, if the valve is open then you will find the lever very loose and floppy and easy to pull with no resistance, if it has a fairly still resistance when pulling the lever then its not energized or the motor/gearing could be kaput, but because its firing the boiler sometimes then looks very like the end switch and you will probably find the lever loose.