M
michaelp
I have a 210 litre Santon unvented hot water cylinder. The house was built just less than 5 years ago. Yesterday it was dripping through the Tundish whilst the water in the tank was heating (indirect from a Vaillant boiler). It stopped dripping when the water stopped heating. It was dripping like this 13 months ago and cost me £180 to have the combination valve replaced. The original installer has been back to service the boiler annually, and also been to do any other work we've needed, although it's a nightmare getting hold of him. He's a really nice chap, but has more work than time. I have left a message (but doubt I'll hear anything anythime soon as it can take months to get them out). To the best of my knowledge, they have never checked the pre-charge pressure in either the Extravalem unvented expansion vessel or the Boss vessel on the closed heating circuit. Instructions say these should be checked annually.The Santon instruction book says that if it's intermittent, re-charge the expansion vessel to 3.5bar (it also says if it's dripping continuously, check pressure and replace the 'Pressure reducing valve cartridge' (rather than the entire expensive combination valve) or clean the strainer).The Extravalem expansion vessel is located awkwardly behind the hot water tank, about half-way up the said tank, and has the water entry at the top. Santon's schematic shows the vessel placed higher up and bottom entry.I would be very grateful for some opinions on this please, as I am rather wondering whether the right job was done last winter or whether it actually needed the pre-charge re-pressurised?I would also appreciate any comments on the vessel being installed top entry, although suspect it doesn't matter.(I had an expansion tank in a previous house, but that was only for a negative head 'shower' pump and I was instructed how to annually check and adjust the pre-charge by the manufacturer's engineer. I'm a Chartered Physicist so I do understand and appreciate the importance of proper operation of an unvented hot water tank, and feel I'm currently depending on a safety device to prevent failure)Thank you.
