I have a Range Tribune HE 210L unvented indirect system with an Ideal Logic System 18 Boiler. Over the past few months water has been constantly flowing from the overflow pipe outside. (filling a 7ltr container a few times a day) I have had a plumber come and check everything over, service the boiler and replace the PRV and the internal expansion vessel in the boiler, however the problem still continues. The system pressure (theres a gauge on the boiler and on the hot water cylinder) is always re-set to 1-1.5bar as per the guidance in the manuals. However within 10-20 minutes the pressure is back up to 2.8-3bar, with the boiler switched off. If the boiler is turned on, it creeps up to 4bar. There is only 1 filling loop to the system which is disconnected. When the cold main to the system is shut off, the pressure holds at 1-1.5 bar. When it is turned back on, it shoots up to 2.8-3bar again. The diagnosis from the plumber (who seems to be very good) is that the coil inside the cylinder has split. Is this likely? However, having spoken to the manufacturer they said it is very unlikely this is the case and there would be noticeable discolouration to the hot water, which there isn't. Any advice would be appreciated, thanks.
The primary flow and return to the cylinder could be disconnected (partial drain down). Turn the main back on at the cylinder and observe if water exits from either connection. This would check if the coil is at fault.
It certainly sounds like mains water is entering the system. It can only really enter via the filling loop or coil.
Thanks for the reply, This hasn't been checked yet, so I will see if the plumber can come out and double check before I pay out £1500 for a new cylinder.
I've only recently moved into the property, which is 3 and a bit years old, the previous owners didn't bother servicing anything and the guarantee is now void.
That's not good. The servicing on these is fairly basic. If it is the coil there is no harm in trying to claim of the warranty. https://www.bvt.org.uk/wp-content/uploads/2010/10/RangeTribuneHEcylinder.pdf
Thought warrenty was transferable, make a claim. https://www.kingspan.com/gb/en-gb/p...water-cylinders/tribune-he-indirect-cylinders