At present there is a 3 way valve installed in the pipework but there is no electrical unit fitted to it. I was going to replace this with a new 3 way valve and wire it in.
There has never been a electrical unit (motor) i.e it is a mechanical valve, or the electrical unit is missing/kaput? Sounds very Heath-Robinson to me
What programmer would you suggest and how would the wiring be altered?
Depends on what you want to spend and how much control you need over the system. (e.g separate times for HW and CH, different heating requirements during the day, different requirements at the weekend. etc)
What Room Thermostat do you have?
The pump, HW cylinder and all associated wiring are all in the airing cupboard as well as the boiler and programmer so changing any wiring would not be a problem.
The main switch is also in the airing cupboard
Just to confirm
everything including the
boiler, apart from the room thermostat, is in the airing cupboard.
This will make wiring easier.
If you don't have a wiring centre (WC) buy one, it makes it much easier!
Here is the wiring diagram for a Y plan:
It will need modifying for the Apollo, which needs a permanent supply for the pump.
Assuming the pump is already connected to the pump connections on the boiler, leave this as it is and ignore the pump connections shown in the diagram.
You will need to run a three core+ earth from the WC to the boiler.
Brown from WC Terminal 1 to Boiler L terminal
Blue from WC Terminal 2 to Boiler N terminal
Green/Yellow from WC Terminal 3 to Boiler earth terminal
The fourth core (usually black) from WC Terminal 8 to boiler ON terminal
You will also need three core + earth for the tank thermostat wiring and 4 core + earth (or 2 core +earth and three core + earth) for the programmer wiring.
Decide where you want to mount everything, estimate how much wire is required and then work out which is the most cost effective. It might be cheaper to buy a larger roll of 5 core+earth for everything, even if some cores do not always get used.
