Question for Budding Plumbers

zom247 · 9 Aug 2007 at 17:14

The cold water tap on my bathroom sink has started making a right racket (knocking sound) when I turn it on. Anyone know what's causing this?

Mr Joshua · 9 Aug 2007 at 17:17

Sounds like it could be an air lock.

Edit. Might not be though, I always associated knocking with an air lock

AtreuS · 9 Aug 2007 at 17:40

Sounds like air in the pipes somehow... odd if its not part of central heating system.

( im not plumber )

Sharq · 9 Aug 2007 at 17:53

Could be a mineral build up. Try flushing your water system!

zom247 · 9 Aug 2007 at 18:01

So•H I Gunit H**•mp3 said:
Could be a mineral build up. Try flushing your water system!

Sorry mate, ask me to fix a pc and I'll do it but diy around the house stuff is not my forte

So, how do I flush the system or get rid of an air lock? I can report it to my landlords and get it fixed for free but it takes weeks, if it's something I can do I'll have a bash myself.

Millwall.FC · 9 Aug 2007 at 20:40

Might be a loose pipe knocking against some thing from the pressure of turning the tap on, dont take my word on it though, im a electrician

RatsPom · 9 Aug 2007 at 21:05

zom247 said:
Sorry mate, ask me to fix a pc and I'll do it but diy around the house stuff is not my forte So, how do I flush the system or get rid of an air lock? I can report it to my landlords and get it fixed for free but it takes weeks, if it's something I can do I'll have a bash myself.

Go to the bathroom sink with a bit of hose that will fit over the sink tap outlets. Connect both the hot and cold tap outlets together with said hose.Open the cold water tap and then the hot water tap. Cold water pressure is greater than the hot water pressure as it is usually fed from the tank in the loft or is straight off the rising main. As the cold water pressure is greater it will force any air in the hot water system out into the space at the top of the hot water tank (I think) not sure but I think there will be some sort of automatic air bleed valve on the system somewhere (someone please correct me if wrong). Of course if you are not totally confident with this routine then call a professional and don't blame me if it all goes wrong...this is the way I did it when a so called kitchen installer/plumber who had just installed my kitchen managed to air lock the hot water system at home .

Best of luck