Intro:
I have a flat in Scotland, UK. We live on the 2nd floor. We have been here for about 18 months and we have a (new-ish) Combi boiler holding a static pressure measurement of around 1.6 bar.
Boiler water pressure indicator increases by about 0.2 bar when central heating is on.
First Notice:
We usually have no need to check the pressure and we found to our surprise a few days ago that the hot water (washing) was not heating, checking the boiler it had a stated pressure of only 0.3 bar, and so the boiler was not firing.
The water flowed out the taps are at a suitable speed.
I hooked up the repressuring inlet tube and raised the boiler pressure to 1.9bar. This is the first time we needed to do this in 18 months.
Ongoing Concern:
From that day, I have been keeping an eye on the stated pressure of the boiler -- and the pressure is decreasing by about 0.2bar a day, right now it is 1.1bar . There has been a little central heating usage in the last few days (1-2 hours only) but I'm curious as to why the pressure seems to be dropping so persistently and if this cause would bring it down to under 0.5bar as before.
Observations:
- We live in Scotland. The water does not contain limescale.
- I have extensively checked all visible pipes and no indication of any leak was found.
- Tap pressure hot/cold are roughly equal, cold tap pressure is not an issue.
- We have a new (18 months ago) Combi gas fired boiler fueling hot water and central heating.
- My only point of pressure measurement is the boiler display which is dial rather than digital.
- Radiator heating circuit is set to be turned on manually so we never have the heating on without doing so ourselves.
- Boiler is "Logic Combi ESP1 30". Boiler was installed new at property purchase.
Other Q&A on here:
I have read Low water pressure which sounds similar but the question deals with a lot of (technical?) stuff I don't recognise (their pressure guage for instance). I also viewed and a few similar posts but which seem to deal with fast/sudden pressure drops rather than gradual persistent pressure drops over time.
Question:
It feels like something's changed because previously this has never been a notable issue and certainly pressure has never fallen below 1bar in the last 18 months.
What else could/should I be looking at/for in order to try and establish the cause of this?
How can I fix this if needsbe?