Vaillant Turbomax 242/E Ignition flashing light

[matabufalez]

Good morning everyone,

I was making some maintenance task in my house, so I remove the radiators from the walls.
Well, now I am trying to start again the boiler, but with the CH disabled (swith just in hot water).
When I try to run it, the Ignition light becomes to flash and nothing happens, except the hot water indicator demands is on.

The Ignition light blinking in the manual means:

"(A flashing indicator shows lack ofwater or poor water circulation in central heating system.)"
But I am quite sure the microswitch from hot water is being actuated since it is detecting hot water demand and trying to start the sequence (it makes some noises when I start the boiler and open a tap, but after a few seconds of noises, the ignition light starts blinking.

I don´t know if I can start the boiler without pressure in the CH circuit, just the hot water, but if i select just hot water on the selector, it sounds acceptable.
What could be my first approach? I ´ve read here about the diff pressure switch, but i really don´t know if it could be the reason

Thank you!

 

[terryplumb]

If there is no water in the central heating system ,that's very likely why your boiler will not fire up.

 

[matabufalez]

If there is no water in the central heating system ,that's very likely why your boiler will not fire up.

Seems logic, but since there is a hot water position for the switch, I was thinking I could start up the boiler withouth the central heating.

Thank you for the reply!

 

[terryplumb]

The central heating water is heated,and passes through the heat exchanger that transfers the heat to Your tap water. In hot water position only ,the flow to the radiators is closed off , but the Central heating water still circulates within the boiler. So ,no water in the system and boiler doesn't function.