Arrived back home, during the early hours, having decided to pack up the caravan, awning etc., at 1am because I was feeling quite ill, and thought better to be at home ill, than in a remote field. Arrived home, and took the heating system out of 'holiday mode', and back to normal operation, then set it to boost the hot water, except water in cylinder, didn't get any hotter. Waited until the scheduled time for it to heat the water, and still it didn't heat the water. Boiler working fine, handling CH perfectly, when called.
At that, I went into full diagnostic mode, pulled everything in the airing cupboard out, to better access everything - swapped the MOMO valve head, to a new replacement - nothing. Checked the thermistor cylinder temperature sensor, fine. Lots of head scratching, up and down stairs, rebooting system - nowt made it heat the water in the cylinder. I even began to think the VR65 control had become faulty. Getting desperate for a good soak in the bath, Ev suggested giving up for the day, and just put the immersion on to get a bath.
There I was, soaking in the bath, when it suddenly dawned on me, what was wrong - before the holiday, on the Friday, I'd set the water temperature for the cylinder, when the boiler heats it, to 34C. To 34C, so we could make use of the free hour of Octopus power, using the immersion heater. Once the HW temperature was reset to 65C, we got a full cylinder of hot water. I just need to restore everything back in the airing cupboard.
At that, I went into full diagnostic mode, pulled everything in the airing cupboard out, to better access everything - swapped the MOMO valve head, to a new replacement - nothing. Checked the thermistor cylinder temperature sensor, fine. Lots of head scratching, up and down stairs, rebooting system - nowt made it heat the water in the cylinder. I even began to think the VR65 control had become faulty. Getting desperate for a good soak in the bath, Ev suggested giving up for the day, and just put the immersion on to get a bath.
There I was, soaking in the bath, when it suddenly dawned on me, what was wrong - before the holiday, on the Friday, I'd set the water temperature for the cylinder, when the boiler heats it, to 34C. To 34C, so we could make use of the free hour of Octopus power, using the immersion heater. Once the HW temperature was reset to 65C, we got a full cylinder of hot water. I just need to restore everything back in the airing cupboard.

