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General Plumbing and Gasfitting Talk => Plumbing => Topic started by: roberto on July 27, 2018, 08:44:02 PM

Title: H J Cooper cylinder banging
Post by: roberto on July 27, 2018, 08:44:02 PM: hi guys,

just got called out to a job this evening, 4 other plumbers have been prior to me...this has been going on for a year!

its a mains pressure h j cooper hot water cylinder that makes a banging noise randomly, its a very loud bang that you can hear all through the house,

i was sent by apex to replace the cold water expansion valve, I isolated the two ball valves either side of the cwe at the inlet to the cylinder, opened up the lever on the cwe to relieve the pressure and the bang went off like a shotgun, then the drain oin the cold water expansion felt hot.

is there anyway it could be a issue with the tempering valve non return? the take off line on the cwe does go up to the tempering valve,

from what the customers have told me ALL the valves (including the limiting valve in the garage ) have been repaced

the customers are starting to get frustrated.....
Title: Re: H J Cooper cylinder banging
Post by: robbo on July 31, 2018, 11:38:45 AM: hi guys, Roberto i have a 2006 300ltr `H J Cooper h/p cyl myself but dont have the problem you describe, have you contacted `RINNAI`as they took coopers over some time ago sounds like a strange problem that will/could result in a serious leak, needs sorting for sure, good luck and keep us posted, cheers
Title: Re: H J Cooper cylinder banging
Post by: Plumber on July 31, 2018, 01:52:17 PM: I have had this issue before. It will be a faulty element ARCING under water.
Title: Re: H J Cooper cylinder banging
Post by: bowtieboy on August 01, 2018, 08:25:51 PM: surely a arcing element would pop a circuit breaker or rcd !due to earth leakage

what model coopers is the cylinder? stainless steel coil wet back by any chance ?
Title: Re: H J Cooper cylinder banging
Post by: robbo on August 06, 2018, 10:28:31 AM: hi guys, yeah very strange, i suppose expansion and contraction could let a drop or two in then seal before arcing but i imagine that the element would slightly `faulty`from new, long shot but.... cheers
Title: Re: H J Cooper cylinder banging
Post by: Plumber on August 06, 2018, 10:49:02 PM: Hi Robbo, not externally. Im talking about inside the tank and submerged under the water if the element has a crack it will arc under water and cause a banging noise. This is not uncommon when the element is on its way out or damaged for other reasons.
Title: Re: H J Cooper cylinder banging
Post by: Brassfield on November 13, 2018, 04:02:11 AM: How loud is that banging noise if the element has a crack? Is it unmistakable? I'm having a paranoia that I'm hearing something like that.
Title: Re: H J Cooper cylinder banging
Post by: Plumber on November 13, 2018, 06:30:32 AM: It can get pretty loud