Question About Recharging a Water Hammer Arrestor on an Open System All aspects of plumbing questions and answers, help, tips and information

[RobDoesDIYDoctor]

Hi,
Can anyone advise what procedure I should follow to recharge an arrestor on an open system, i.e. a system that feeds the cold taps, an instant shower, a toilet cystern and also provides the feed to obtain hot water from the combi boiler. The arrestor is, I believe, located on the cold feed pipe that divides into two branches, with one side going to the combi boiler and the other side going to the instant shower.

I've tried uploading a photo of the pipework showing the arrestor without success. A photo of my set up can be seen at:
http://tinyurl.com/mky564g

(If that link doesn't work please copy it and paste it into your browser.)

Many thanks.

[thedoctor]

Hi,

The usualway of recharging a basic air valve waer hammer arrester is simply to turn off the water at the mains then drain down all the water in the hot and cold pipes by opeing all taps and any drain cocks you have near the rising main. When you are sure all water is out of the pipes, close everything up again - taps and drain cock/s.

Then turn on rising main. The air willautomatically recharge as the system refills. When the system, tank etc is all full, open each tap slightly to remove ant air from the main pipes.

Please do let us know how you get on as your feedback could help loads of others with a similar problem.

[RobDoesDIYDoctor]

Thank you to everyone who has posted a reply to my query.

What seems to have worked for me is to do the following:

My arrestor needed to be recharged to 3.5 bar (50 psi)

I turned the water off at mains. Then opened cold taps only until the pipes drained. Then I attached a bicycle shock pump to the arrestor valve and pumped up the arrestor to 50 psi. Then I turned off the cold taps and opened up the mains. I waited a couple of minutes for the cold pipes to fill.

Then I opened up the cold tap downstairs to make sure the cold water flow was at the required pressure. Then I closed the downstairs cold tap. Then I opened the bath and wash hand basin cold taps upstairs. The water coming from these sputtered and spat because of air in the system. I closed the wash hand basin cold tap but left the bath cold tap running. I turned my shower on to cold and left it running for 1 min to purge all the air from the system. Then I closed the bath cold tap but left the cold shower running for another 30 seconds or so.

This seems to have worked as I am on longer getting the water hammer in the pipes.

[Devk89]

Thanks followed your steps and fingers crossed my shock arrestor is recharged and not noisey any longer.