I have checked the wire, and seem not problem.
I have use the "testing heating" from Nest thermostat and it is work, the boiler status show "C" and burner light was on.
I am thinking if the heat function okay, the only possible problem of wire shoulg be the one at Nest terminal 6...
And i find that there is no hotwater testing on Nest thermostat, only heating, is it normal?
The cylinder may heat up because my wife truned on the hot water function with the old programmer this morning for showing, maybe i need to test it again tonight?
I found the problem finally.
i use this type of connector for connecting some of the wire together, and i have change the connector to a new one, and it's work!
I don't know how to say but just want to let you know i am really thank you for your help.
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