I had problems with my 4 year old Ideal H24 heat only boiler Central heating system. Central heating flow was intermittent and worked most of the time but there was an issue. When hot water was called at the cylinder stat the pump would run and the boiler ran to the default 80C flow temperature. When the cylinder stat was satisfied the pump would suddenly stop even though there was a demand from the room stat. This was an intermittent problem , only showing up occasionally. After much electrical testing I discovered the problem was as simple as this. I loosed off the HSA3 actuator head slightly and the valve started to motor and the C/H started to work properly. Lesson learned.
There must have been some tightness due to slight misalignment between the actuator head and the valve, this stopping the actuator from motoring properly
There must have been some tightness due to slight misalignment between the actuator head and the valve, this stopping the actuator from motoring properly
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