baxi solo he15 cycling on and off

[PCatterall]

I would like to understand the issue before calling in my friendly local engineer.
Over the winter our 8 year old boiler has been fine but is now firing up for a couple of minutes stopping for a couple of minutes then repeating the cycle house rads are all switched off only the cylinder is on.
After someone has showered the boiler fires up for longer then the cycle starts again.
I am assuming that the water in the cylinder reaches its set temp and just switches off.

I would have thought that the boiler would have a built in ability to allow the water to cool off a few degrees before heating it up again but this seems not to be the case.

I see that there is a motorised valve on the pipe to the cylinder and clamped on the pipe is a thermostat. The thermostat is not connected to the valve ( reason unknown ).

I will value any ideas about this and suggestions of what may be wrong.

Currently I am using the time switch to just have 'heating' ( hot water) on for an hour in the morning and evening but thought there may be a more 'sophisticated' solution!!

many thanks

 

[ianmcd]

I see that there is a motorised valve on the pipe to the cylinder and clamped on the pipe is a thermostat. The thermostat is not connected to the valve ( reason unknown ).

is your boiler in an outhouse or garage ? this pipestat that you describe is possibly connected to a frost stat

 

[PCatterall]

Thanks Ian. The boiler is in the house. The pipestat is between the motorised valve and the cylinder. I had read about this cycling on and off elsewhere on the forum and there were some recommendations about having the cylinder thermostat set 10 degrees lower than the boiler thermostat. That was when I discovered that the leads from the valve to the pipestat were disconnected!

 

[ianmcd]

Can you post some pics please not really sure what is happening