Banging Clanging Noise from near Boiler/Pipes near it!!

[MancAnt]

Hi all,Hope Someone can shed any light on the issue we currently have. Last week the water company were working in our area ( though they never told us initially) and we only noticed and raised the issue as our water pressure was really low. Anyway long story short they completed the work in our area and called to say pressure should be back to normal. We now have a strange banging/clanging noise near the combi boiler/pipes upstairs in the cubby hole next to the bathroom that only happens when we turn the hot water tap off in the kitchen ? It doesn't happen when it's cold water from the kitchen mixer tap or from the hot and cold mixer taps in the bath or the sink in the bathroom. Also doesn't happen when shower turned off or on either?? If we turn the kitchen tap on slower and off slower we don't get the banging/clanging noise. Is this water hammer or something else to do with the boiler a Bosch Worecester Junior 28i? I have tried turning the stop tap water pressure down slightly to see if that helps but am at a loss? Any advice-help appreciated

 

[WC1]

Is it quarter turn type tap? If so its probably water hammer as you say

 

[MancAnt]

Is it quarter turn type tap?

Sorry to you mean the actual tap in the kitchen that causes the issue? If so it's a large mixer tap ...attached.
I just find it strange how we didn't have this issue until after we had the water pressure issue when work was being carried out.im wondering if its a pressure issue?

 

[WC1]

Pressure might be a bit higher than it was. Try Al's suggestions from the vid - look for loose pipes etc. Unlikely to be related to the boiler

 

[MancAnt]

Pressure might be a bit higher than it was. Try Al's suggestions from the vid - look for loose pipes etc. Unlikely to be related to the boiler

Will do mate. I'll turn the stop tap off completely tomorrow then turn it back on gradually until I get a decent flow rate and see if problem still exists. Strange how the tap (the only item doing it ) is furthest away from the boiler and it's only the hot water???

 

[MancAnt]

I've attached a video of the noise I've recorded ..pipes or boiler ? Filmed in cubby hole on the landing where the boiler is installed 7-8 seconds you can hear it .
# I cannot add the 20 second video in mp4 format ??

 

[MancAnt]

OK so I have turned the stopcock pressure down by a quarter turn then another quarter turn but still get this noise near to the pipes near the boiler or from the boiler only when hot water tap turned off after being initially turned on in the kitchen only?? Any other ideas anyone?

 

[MancAnt]

Pressure might be a bit higher than it was. Try Al's suggestions from the vid - look for loose pipes etc. Unlikely to be related to the boiler

OK so I have turned the stopcock pressure down by a quarter turn then another quarter turn but still get this noise near to the pipes near the boiler or from the boiler only when hot water tap turned off after being initially turned on in the kitchen only?? Any other ideas anyone?

 

[ShaunCorbs]

Turn the tap off slowly need a shock arrestor fitting

 

[MancAnt]

Turn the tap off slowly need a shock arrestor fitting

Yeah I've tested it again Shaun and it definetly doesn't happen if you turn it off slower (the kitchen mixer tap). What I don't understand is this didn't happen until we had initial lw water pressure problems ( unitised utilies were working in the area). They told me to do the "turn off water mains/stop tap,turn on taps on 1st floor,then ground floor allowing all water to drain then once drained turn stop tap back on allowing water to flush out any air". They said could be water hammer!
Where would we fit the shock arrestor specifically?
Is it dangerous ?

 

[ShaunCorbs]

It’s common when you have high pressure and a fast closing tap

It will be fine if you learn to close it slow or have a shock arrestor fitted below the boiler

 

[MancAnt]

It’s common when you have high pressure and a fast closing tap

It will be fine if you learn to close it slow or have a shock arrestor fitted below the boiler

 

[MancAnt]

Sorry for not getting back to you sooner Shaun...... is it dangerous? Like you say if you turn the kitchen mixer tap off slowly or it's just cold water feed and you turn on and off you don't get the banging/clatter noise from the pipes below the boiler fitment?

 

[Ric2013]

Dangerous? No, but the transient pressure surges through the pipework won't be good for them in the long term if they are rattling around.

By the way, throttling down your stopcock will limit maximum flow and not maximum pressure. If you want to reduce your pressure, fit a pressure regulating valve.

 

[MancAnt]

Dangerous? No, but the transient pressure surges through the pipework won't be good for them in the long term if they are rattling around.

By the way, throttling down your stopcock will limit maximum flow and not maximum pressure. If you want to reduce your pressure, fit a pressure regulating valve.

Thanks for the response Ric2013. Having spoke to our plumber on another issue we had (float valve issue now sorted) he stated that ideally you should always turn your stopcock open fully and then turn it back at least a half turn so it doesn't seize. So currently is left at just that .
It is really strange how we didn't have this issue until a few months ago when United Utilities were working in our area and the pressure was low ( they didn't admit it at first) and they initially told me to turn off the mains water at the stopcock and then turn on all taps upstairs,then downstairs to flush my system of any trapped air. Then once all empty to turn on the taps from upstairs to downstairs (bathroom taps then kitchen and outside tap) to flush an air out of the system possibly causing the low pressure .
It is literally when we turn off our Blanco mixer tap when running hot water in the kitchen only...