possible dead leg in hot water system

[jbw1]

Hi,
I've just had a mixer valve shower fitted and this works from my Puma Potterton 80 combi boiler system.
When I turn the cold water on and off, I get a clicking sound from boiler as though it is firing up but it's only for a split second.

Is this a dead leg caused by an air gap in the hot water system.
How do I overcome this?

Thanks Jim

 

[bengasman]

Have you left a dead leg?

 

[gaspro1981]

turn the cold mains supply to boiler off and try operating a cold tap and see what happens then

 

[jbw1]

Thanks for the replies. No dead leg left in system.
I think it's just trapped air which seems to be improving gradually.
Cheers Jim

 

[bengasman]

So where can it be trapped if there is not dead leg?