Help needed following air in pipes problem

[islandman]

Somehow a build up of air has occured in our water pipes manifesting itself in a 'trombone' like sound coupled with vibration in the cold taps when the upstairs lavatory cysten concludes each refill.

I turned off water at mains, switched off combi boiler and opened all taps. Air could be heard expelling so I left it like this for an hour of so.

Closed taps & turned water back on (not boiler) and opened taps. Loads of hissing and spurting etc but in the end it settled down and the noise is gone.

Turned boiler back on.

I have noticed that since doing this when I turn a cold tap off the boiler starts up momentarily ---- it never did this before. If however I turn the cold tap off slowly nothing happens --- it only seems to do it if I turn the tap off sharply.

Any ideas on why this would happen? The hot water works fine.

Boiler is a Vaillant Ecotec 831 combi

 

[Razor900]

Sounds very unlikely unless air splutters out the taps when you turn them on!

Time to change the wc inlet valve methinks

 

[doitall]

Yep, agree with Razor, Typical plastic ball valve noise. new valve or change the diaphragm.

 

[islandman]

Right ok & thanks for the pointers ---- but any ideas on the boiler now behaving differently. May be just a coincidence.

 

[doitall]

May be more than one problem so get the ballvalve sorted first.

 

[Razor900]

The boiler firing up momentarily when a tap is turned off is a classic sign of trapped air in the pipework, just like you would get if someone turned off the main and opened all the taps - Oh, like you did

Run every outlet in the house for a couple of minutes each not forgetting any unused drawoffs (like an unused washing machine hot supply) and tell us if the problem stops.

 

[Muzz]

i also had the trombone sound on toilet refill and thought my plumbing had major problems,

eventually figured out it was the ball valve, easy job to diy replace!

 

[islandman]

OK & thanks ---- I guess it was an easy 'try' just to turn of the water, leave the taps open & see what happens.

Razor --- thanks, I'll try what you say. The pressure does seem different since I did what I did. Seems alot higher initially and then settles down ok.

Boiler doesn't seem to fire if you turn the cold tap of slowly and the worst offended is the one in the kitchen nearest the boiler located in the back porch.

 

[doitall]

A lot of boilers require a shock absorber on the mains.

 

[islandman]

A lot of boilers require a shock absorber on the mains.

Blimey! ----- would this be with fairly high main pressure? Ours is not particulary high but for some reason it seems higher now!

Also, I know there's a length of blanked off piping upstairs - previous owners were going to convert small bedroon to ensuite but never got round to it but had the pipes laid. Maybe some air has got trapped in these. May be difficult to get out if so

 

[kevplumb]

so cut them off and cap them

if they are full of air its probably your problem

jeez wish i was sober

 

[islandman]

so cut them off and cap them

if they are full of air its probably your problem

jeez wish i was sober

Hah! --- I know ............ but I don't think the good lady will be very pleased with the disruption ESPECIALLY as there wasn't a problem before I did something that as it turns out wasn't necessary in the first place!

 

[doitall]

Tell her that water regs say un-used pipes should be capped at source (the branch) as the pipe contains stagnant water and is a breeding ground for bugs.