Combi Boiler and turning off water supply

[OhGranny]

Hi
I have been doing some work on my bathroom and have had to turn the water supply off a few times.
Now when I turn on the cold tap the boiler pump (or something inside) operates for a few seconds the pressure drops to .8 then goes back up to 1 bar. The boiler doesn't ignite but something runs inside. It never used to do this before!
I have always turned the boiler off when the water supply was off in case someone turned the hot water tap on accidently but I have never turned off the water supply to the boiler.
The boiler still give hot water but I am a bit worried now that something is running inside when I turn on the cold water tap. Something has changed.
I have a manual but can't see any advice or procedure to follow if disconnecting the water supply.
Any ideas or advice please?
G.

 

[sooey]

Have you fitted mixer taps, or created a dead leg somewhere in the pipe work.

 

[kevplumb]

run all the taps one at a time you have air in the pipework

 

[sooey]

It's obviously a combi, so any air can only be trapped in a dead leg.

 

[kevplumb]

It's obviously a combi, so any air can only be trapped in a dead leg.

yup what would you call say a basin feed full of air

or a shower that hasn't been ran

might be obvious to me and you but we ain't there

 

[sooey]

Come on kev, you've got to assume that he's ran all his taps plenty, after doing new work and before posting on here.

 

[sooey]

and stop editing your posts you bugger.

 

[kevplumb]

never assume anything on here

like my boiler wont work on heating

have you turned the selector to water / heating

oh thanks it worked

 

[sooey]

 

[OhGranny]

Thanks lads that's put me at ease a bit at least the boilers not K********d.
I've got the bath out at the moment to plaster so the taps hadn't been run the bath pipes had air in.
I undid the taps and a large gush of air came out the combi seems O.K.
In future should I turn off the water supply to the combi boiler when I turn off the water?
G.

 

[sooey]

I've got the bath out at the moment to plaster so the taps hadn't been run the bath pipes had air in.
I undid the taps and a large gush of air came out the combi seems O.K.

Aaaarghh

In future should I turn off the water supply to the combi boiler when I turn off the water?

No need if you turn off the water at the stopcock anyway.

 

[kevplumb]

I've got the bath out at the moment to plaster so the taps hadn't been run the bath pipes had air in.
I undid the taps and a large gush of air came out the combi seems O.K.

Aaaarghh

In future should I turn off the water supply to the combi boiler when I turn off the water?

No need if you turn off the water at the stopcock anyway.

 

[sooey]

That's what I like about you kev, you're so subtle and debonair.

 

[dextrous]

There's nothing like a good winner

 

[kevplumb]

That's what I like about you kev, you're so subtle and debonair.

yup and we have all been caught out at sometime

missing the freakin obvious