gas pressure

[Max5]

how can i check internal gas pressure because my boiler just fires up for 20 sec then cuts off then turn the tap off and back on boiler fires up and goes off again same on CH help please

 

[chrishutt]

If you want to know what's wrong with your boiler, best not to jump to conclusions. Just tell us what boiler you have and what the symptoms are.

 

[Max5]

thank you for reply I have worcester 24i fitted about 2 yrs ago worked fine now when turn the hot water tap on fires up but cuts off after 20 sec while the water is still running, does the same on CH i replaced the pcb ,air p switch,thermistors,but problem is the same,pump runs elec there thanks

 

[Bamber gaspipe]

thank you for reply I have worcester 24i fitted about 2 yrs ago worked fine now when turn the hot water tap on fires up but cuts off after 20 sec while the water is still running, does the same on CH i replaced the pcb ,air p switch,thermistors,but problem is the same,pump runs elec there thanks

Gas valve?

 

[Paul Barker]

blocked heat exchanger?

 

[ChrisR]

Yes, or clogged up pump.

Would you post me all the perfectly good bits you've removed??!