On 10/03/2019 07:55, harry wrote:
On Saturday, 9 March 2019 18:25:13 UTC, John Rumm wrote:
So far all the normal tricks don't seem to be doing it!

Short version:

There is a leak somewhere in my central heating system - its losing
pressure regularly, and needs topping up with at least a couple of
litres a day.

Any bright ideas?

Leak on heat exchanger of boiler itself.
They can leak only when it's firing/hot.
Water evaporates so not necessarily any drips.

A leak into the combustion chamber is possible. The outside however it
spotlessly clean.

I will introduce a pressure valve into the pipework separate from the
boiler's internal one, then I can isolate the boiler form its pipework
and see if I can eliminate one or the other.

Tie plastic bags over PRV vents, it only leaks as water heats up.
And when it's topped up.

Already tried that.

Does it lose water when not running?

Its not usually off for long enough at this time of year.


--
Cheers,

John.

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