Megaflo thermostat wiring question

[RichLaw]

Hi
I have a indirect megaflo system and the boiler is always showing demand to heat the hot water even when the water in the cylinder is hot. The thermostat and valve seem ok as far as I can tell. I suspect a wiring issue from the cylinder thermostat to the 2-port valve.

It looks like one of the thermostat wires is connected to the programmer HW On AND joined to the 2-port valve which seems suspect.
Can anyone confirm if this wiring looks correct or not?

I have 2 connections from the megaflo thermostat these are connected as follows:

1 (brown wire) <-> programmer HW On (yellow wire)
<-> HW 2-port valve (brown wire)

2 (blue wire) <-> boiler (blue wire)
<-> HW 2-port valve (orange wire)
<-> CH 2-port valve (orange wire)

Thanks

 

[muggles]

Although probably more importantly, you shouldn't be working on an unvented cylinder unless you have a G3 qualification to do so, as it is a controlled appliance...