I have recently moved into a house with the following heating system:
The system is behaving strangely and I'd like an overview of the cause of the problem before calling a plumber out.
This is what I have observed:
Bluto
- Traditional boiler (Worcester Greenstar Ri 24 with only one temperature dial and no pressure gauge)
- Vented central heating (cold tank in loft)
- Unvented hot water (Excelsior cylinder with pressure gauge plus white expansion vessel above)
The system is behaving strangely and I'd like an overview of the cause of the problem before calling a plumber out.
This is what I have observed:
- The good. When the boiler is set to "hot water only", everything seems fine. The pressure gauge by the cylinder goes from 2.5 bar to about 3 bar over the course of 30 minutes or so as the water is heated and settles at 3 bar. Increasing the flow temperature on the boiler doesn't cause any issues: the pressure in the cylinder doesn't go beyond 3 bar. I'm guessing this means the cylinder thermostat and expansion vessel are doing their jobs fine.
- The bad. However... When the boiler is set to "central heating only", things don't work as expected. The radiators work fine, but the hot water is still being heated. The pressure in the cylinder gradually increases from 2.5 bar to 4 bar (the end of the scale) over the course of a couple of hours, showing no signs of slowing down, at which point I shut off the heating for safety. Exactly the same happens when the boiler is set to "both central heating and hot water". I tried lowering the flow temperature of the boiler so the radiators weren't piping hot, but the issue persists.
Bluto