"summer mode" to keep radiator valves open during summer
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The problem is: If I connect all the smart radiator thermostats to my zone controller and I don't want to heat any room (because it is summer now) this results in all the radiators being 'closed' (or 'blocked').
This makes the total central heating system volume smaller (since the radiators are essentially cut off from the total volume of the system, they're 'blocked').
Now when I tap hot water from my shower for example, the water in the remainder of the central heating system warms up a bit (due to thermal radiation in the combi-boiler) and the water expands. This causes the pressure in the central heating system to increase too much.
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