Water Hammer since installing push fit tap tails

[M A Preston]

Today I installed some push fit plastic tap tails under the sink. This replaced the previous flexible hose (4 in total joined together by last owner - don't know why). I also installed some push fit appliance taps that will go to a water filter and a dishwasher.

Ever since when any tap in the house is shut off I get water hammer. Hot or Cold.

I have drained the system by shutting off the stopcock and letting all taps drain. I thought this cured things until later I went upstairs and used the hot tap and bang again it was back.

Should I try bleeding the rads?
Could it be the push fit pipes installed incorrectly?
Is this going to be a nightmare to troubleshoot?

Any suggestions welcome!

 

[Riley]

Rads and domestic water are separate shouldn’t make a difference. Is your stopcock fully open again

 

[Scott_D]

Have you opened all taps and outside taps?
Could be some trapped air

 

[M A Preston]

Yeah it's for sure trapped air. The problem is I don't know how to remove it.

The stopcock is open, yes. I've been told to maybe turn this shut a bit to see if that reduced pressure? But then I've also been told pressure is constant so this won't do anything.

I have tried to remove the air by shutting off stopcock and opening all taps - but I don't know if it matters how long for? I just did it until all water stopped, then turned on stopcock.

The reason why I ask about central heating is when I drained the system first time (I've done it now about 6 times) the knocking went away UNTIL I used a hot tap upstairs and then all taps started knocking again.

So either air is somehow getting into the system since my modification, or I have not got the air out properly in the first place. I can get it so the downstairs taps make no effect but then if i use the upstairs taps they start to splutter and when I shut off the hammering returns to all taps on system.

I am worried this will cause a leak somewhere if I cannot fix and I've just had all my electrics redone, down lights and plastering everywhere.

Thanks for replies so far!

 

[Scott_D]

If you have run every tap. Flushed the toilets. Checked the outside taps. Run showers etc the air should be out

Unless you have a dead leg of pipe somewhere
Eg you have a combi boiler now but originally there Wes a boiler and cylinder and some old pipe is still under the floorboards

 

[Riley]

What boiler do you have

 

[M A Preston]

The boiler was moved outside into the attached garage.

We have a brand new (3 months old) baxi boiler.

To the best of my knowledge there are no dead legs.

Since this issue didn't occur before I'm guessing it is fixable without the use of arrestors - is this correct?

Could my water pressure be causing this issue?

 

[Riley]

Combi boiler?? Apparently several manufacturers now require an arrestor. Not a baxi expert so maybe one of my colleagues can enlighten us

 

[M A Preston]

Yes it is combi boiler.

I don't mind installing arrestors IF they are the done thing - I don't want to simply be masking a problem with a hack type device.

As I said before - there was next ot no water hammer before installing these bloody taps. Now it has affected the entire system.

I am tempted to do the whole house in push fit to see if that will cure the knocking.

The 15mm copper is old and I don't trust it if this continues and I can't resolve. Any water source causes hammer and two days ago we never heard it.

 

[rpm]

As I said before - there was next ot no water hammer before installing these bloody taps.

No swearing!

 

[Riley]

Are you just talking the washing machine Taps

 

[M A Preston]

No buddy.

Every water source in the house now causing water hammer.

All I changed was some flexible hose under the kitchen sink to some plastic push fit tap tails. Since then the hammering has begun.

I am now wondering if the meter plus of flexible hose used to connect to taps prior was absorbing some or all of the hammer.

In which case will simply installing an arrestor anywhere on the system fix the issue?

Could my water pressure be too high in which case will a pressure reduction valve at the stopcock solve this?

Anyone got any ideas?

 

[Riley]

Realistically two things happened you changed the pipe and you turned off the stopcock.
Has anybody suggested the innards of the stopcock vibrating?

 

[M A Preston]

No one yet. Would that cause the loud clunk when turning off any water source? There is no noise when water is turned on from any source?

 

[Riley]

It’s where id look. Cheaper than re-piping your house

 

[M A Preston]

This has now been fixed.

Turns out I needed to turn my stopcock all the way open. not semi closed as I have been told by a few sources.

This has now resolved the matter.

No idea how.

 

[townfanjon]

This has now been fixed.

Turns out I needed to turn my stopcock all the way open. not semi closed as I have been told by a few sources.

This has now resolved the matter.

No idea how.

Honestly don’t leave it fully open , just turn it back in about a 1/4 to 1/2 turn , helps stop it seizing.

 

[M A Preston]

Will do!