Water Heater Expansion Vessels
I have seen a number of posts on here regarding badly installed expansion vessels on domestic hot and cold water systems. Here's one identified in a risk assessment for a school. This was fitted to a 10 litre undersink water heater but when i checked the installation instructions they made no reference at all on how to position the expansion vessel.
Should'nt the manufacturer have a responsibilty to ensure he spells this out especially when they quote how their product meets WRAS, KIWA, EU regulation this and regulation that....
I spend a disproportional amount of my time and precious resources having badly installed expansion vessels replaced and fitted correctly. We know there is a training gap for Legionella awareness in the industry, (evident by the shrug of shoulders when I try and explain to some plumbers) even though the information has been out there for years. WRAS and the ACOP L8 HSG 274 pt 2 tell you how but its not filtering down to the man on the ground (or in a cupboard)
To try and address this, and other design/installation queries, I have started to provide the project teams, design consultants and contractors with a 'Water Hygiene Briefing Note' which includes how to install an expansion vessel..
(i.e. all expansion vessels installed on domestic hot and cold water systems must be mounted vertically preferably of the through flow type or with the connecting pipework as short as practicable with a means to isolate, drain and flush (Water Safety Plan) Alternatively, an anti-legionella valve can be used on certain connection sizes).
More needs to be done and one day, the above photo will be rarety.
Was the installation approved before the invoice was paid? Probably not. A common occurrence?
Minor Works Foreman at Durham County Council
6 年Recently we have been supplied with combination valves (pressure reducer/relief/none return) which has a female thread for an expansion vessel to be fitted horizontally. I am G3 qualified and have installed a few water heaters this way. Is this incorrect?
IHEEM Registered Authorising Engineer (water)
6 年Haha.i know I remember it well. They were unable to verify anything . Even how it would or would not flow around a vessal body
IHEEM Registered Authorising Engineer (water)
6 年Anti legionella valves is a myth ... check out WRAS. It states on their register , directory the anti Legionella valve has NOT been tested by WRAS for controlling Legionella, the valve is tested only for material component.
OEM Director at Global Water Solutions
6 年Paul great article. You are correct that the information and recommendations given by HSG274pt2 is not getting to the plumber. Your initiative is excellent, I will contact you to ask for a digital version of your leaflet so my company can distribute globally. One further point to add is there is already legal precedent on the failure to install to ACOP standards. So prosecution is on the cards!!. Ignorance is no defence.