Vokera Linea 24 help required

[tooley3000]

I have a Vokera Linea 24 combi boiler that when i turn the tap on it just lights for 5 seconds then go`s off for 5 seconds continuously.My heating seems fine.
I have water coming out of the pressure release valves overflow pipe,not a great deal more of a drip,so i changed the pressure release valve but to no avail.I have been told that it may be the expansion vessel,so i purchased a new one,not before i checked the old one to see if it had lost any pressure,which it hadn`t.When i removed the new expansion vessel from its box i noticed that the gauge of the threaded connection was larger than the pipe and nut i was supposed to connect to it,so i couldn't use it.
Every now and again my boiler will start normally when i turn on the tap.
Has anyone got any ideas.By the way the Vokera is approx 10years old

 

[nickso]

you have more than one fault by the looks of it.

read the FAQ's on recharging your vessel. if you have changed the prv and still get water out of the pipe then the vessel is probably not charged properly.

when you do get the boiler working normally on those odd occasions does the water get hot? or is it luke warm or cycling hot and cold?

if it does work normally then its probably either a burner pressure issue or more likely the gas valve pcb is faulty.

 

[tooley3000]

Thanks for the reply. When the boiler does get going the water is always hot.The pressure gauge does tend to go to about 2bar with the temperature reaching about 63 to 70c.
When i repressurized the expansion tank i emptied the water out through the prv overflow pipe but, correct me if i`m wrong,i should have pumped some air in and released it again through the prv just to make sure all the water was out.I just repressurized it to the correct setting in the manual. Do you think i should re pressurise the expansion tank?

 

[nickso]

yes, do it again and open the prv to let the water out until its stops.