Hi
I have an old conventional vaillant boiler vu-242eh that until recently has worked fine. Now, when it is cold it fires up with no issues whenever the heating or hot water is switched on. However after a minute or two it goes out, almost as if the water in the system is up to temperature.
After the usual delay it tries to fire up again. The fan is on, the ignition goes, the boiler lights for a fraction of a second and then goes out. It then repeats this constantly until it eaither suceeds or locks out. Its almost as if the flame lights but is blown out.
The fan is fine, pressure is ok and the pump is working. In a fit of frustration during an ignition sequence I did give the front of the combustion chamber a thump and it fired up (only to go out again after a minute). Subsequent gentle thumps have also proved successful leading me to think something is sticking, is blocked or there is a pressure issue from the fan. The fact it is fine when cold also leads me to think something is expanding and either sticking or losing pressure.
An ideas? If the thing never started then the failure may be easier to trace but this is a failure when hot and the control unit must be getting the correct signals as it tries to light but doesn't quite make it.
I am looking for a knoweldgable engineer at the moment as past experience has shown me many engineers are not always familiar with this model and use the replace one component at a time approach without fuly understanding the root cause of the issue.
thanks
I have an old conventional vaillant boiler vu-242eh that until recently has worked fine. Now, when it is cold it fires up with no issues whenever the heating or hot water is switched on. However after a minute or two it goes out, almost as if the water in the system is up to temperature.
After the usual delay it tries to fire up again. The fan is on, the ignition goes, the boiler lights for a fraction of a second and then goes out. It then repeats this constantly until it eaither suceeds or locks out. Its almost as if the flame lights but is blown out.
The fan is fine, pressure is ok and the pump is working. In a fit of frustration during an ignition sequence I did give the front of the combustion chamber a thump and it fired up (only to go out again after a minute). Subsequent gentle thumps have also proved successful leading me to think something is sticking, is blocked or there is a pressure issue from the fan. The fact it is fine when cold also leads me to think something is expanding and either sticking or losing pressure.
An ideas? If the thing never started then the failure may be easier to trace but this is a failure when hot and the control unit must be getting the correct signals as it tries to light but doesn't quite make it.
I am looking for a knoweldgable engineer at the moment as past experience has shown me many engineers are not always familiar with this model and use the replace one component at a time approach without fuly understanding the root cause of the issue.
thanks
