Is central heating leaking - please tell me no!!

M

munstershug

Registered User
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Folks,
I have multiple problems with my Vokera Mynute 20e boiler. A burst expansion vessel balloon (venting water from recharge valve) and a leaking heat exchanger. I am probably going to replace the whole thing and get a powerflush on the 12 year old system. However a long-time nagging doubt as be asking the question here.
One of the tiles in the kitchen floor about 1ft before the first radiator, and about where I believe there is a tee into the playroom rad gets warm over a diameter of about 6-10inches - is this definitely a sub-floor leak - how do I tell? There are no isolation valves on the flow and return pipes from/to the boiler, except for the zone valve for downstairs. Pressure does drop but I cannot tell if that is from the heat exchanger or the sub-floor pipes.
Should I run leak sealant through the system before I put a new boiler on or after?
Any opinions / suggestions greatly appreciated. It's going to be fun run into Christmas this year!
 
If you have a leaking heat exchanger and a deflated vessel, both these will drop your system pressure.
A floor getting warm would not necessarily be a leak. If you have a second pressure gauge on the system, you could isolate the boiler by turning off the flow & return valves below the boiler and see if there is a pressure drop on the system without the boiler connected.
 
Thanks Shane of course the high quality standards when the estate was built meant there are no isolation valves fitted to isolated the boiler from the system. Local plumber came on Sat evening and replaced heat exchanger and fitted external expansion vessel and all seemed good in Sat night with all rads on both zones heating. Plumber said flow was good but could hear air, so I bled all rads.
On Sunday evening however there is no heat going to last rad on ground floor. Even the flow pipe is cold. All rads bleed water. But hear air circulating in pipes in hot press upstairs.

Any suggestions? Could air be trapped or causing air lock.
 
The Mynute 20e has isolation valves built in to it. They are square valves just underneath the boiler.

To get the rads to heat, turn off the cylinder coil balancing valve and turn off all rads that are heating, leaving only the rad that will not heat on.

If it then heats, it is a balancing issue.
 
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