Red and blue are right but yellow goes to NO and you need to put a link between L and C.
Heatmiser neo-stat V2 but at about £55 each and £150 for the hub it won't be cheap.
It's probably knackered so someone has just joined the wires together to get the heating working.
On your new controller:-
Blue to N
Brown to L...
It is probably just the motor in the valve which needs changing (it's most likely jammed in the heating only position) these are about £20 from...
They are both wired exactly the same way.
However, if you have a room thermostat then you will need to either leave it turned up full or...
The orange from the valve and the call from the cylinder stat connect to the RT terminal on the X1 plug on the boiler.
So 3 on the nest should go to the white on the 3 port valve.
4 on the nest to the grey on the valve and satisfied on the cylinder stat.
6 on the...
4 is HW OFF
6 is HW ON
So if you have done it like you say they are the wrong way round.
Have you removed the 24v link on the boiler circuit board?
The yellow wire isn't an earth. It's the switched live, it should go to 3 and the red wire to L
You need a link between L and 1 in the receiver.
The pump has to run with the gas boiler. As the name suggests it pumps the hot water, that the boiler heats around the pipes which in turn heat up...
Your boiler and pump both use electricity when running as well as the boiler using gas.
So when it fires up both will go up on your smart meter.
Yes it can. Looking at the wiring it is almost certainly a Y plan system.
Both blacks in N to N on Nest heat link.
Both red in L to L
Red in 1 to...
Even with the built in programmer?
To the OP press the left hand button on the programmer that says select once this should stop it.
And as I...
That programmer (DT10rf) is for the preheat on the hot water. You have it set to constant so it will always be on.
But having said that the...
It depends on what make the valve is.
Honeywell and Drayton don't, but Danfoss valves do.
Looks okay to me. You can test it by joining the brown and black wires together where the switch will be going. Because after all, that's all that...
Okay your old clock was a 2 channel clock so it's a bit different to the Hive.
What you need to do is put the black wire in terminal 3, the grey...
I didn't get onto it that you had removed a thermostat.
As Chris pointed out you can't just remove it you need to join the live and switched...
Separate names with a comma.