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Boiler pressure drops with no obvious signs of leaking
Anonymous user 09/03/2024 - 3.36 PM
My issue is as followings: 1. My boiler (combi) drops pressure every two days from 2 to 0 and I have to frequently repressure it. A plumber came to check and did not think it is bacuse of expansion vessel as no water drips from the external tube. No obvious water drips from the boiler either. 2. I bled all radiators early November, but by the end of December, I noticed lots of air in the towel rail (1/5 of the whole rail probably). After bleeding, I noticed air in this rail early January again. During this period, I used the radiators a lot. The radiators were installed in August and by early November (when I did not use heating), I only noticed small amount of air in the towel rail. 3. As all radiators are newly installed, I cannot see any water dripping from the valves, nor the ceiling. It is suggested that leaking somewhere in the system. I just wonder about other possibilities before people remove all my floors to check underneath the ground floor. Update: Thanks Mohib for your reply. Another thing I noticed with the boiler is that the pressure seems to stay where it is if I leave the heating on 24hrs a day, but start to drop slowly when I turned off the heating. As I usually only use heating in the evening, that's probably why it drops every day. Another thing I noticed is that as soon as the boiler stops heating the water, the pressure has an obvious drop. I read someone saying the heating can compensate the water loss in pipe leak due to the expansion, but in my case it seems even the water is still hot, as soon as the heating mechanism is off, the pressure will drop still. To me it feels like a boiler issue?
Are you a tradesperson and able to answer this question?
4 Answers
Mohib
The Fixer
Privetts heating & plumbing engineers limited
Firefly Heating Ltd