Potterton ep2000 timer wiring, honeywell st9400a

[Atomix]

Hi guys,
Just need a little bit of help.

currently have a potterton timer with wiring thus:

https://www.diynot.com/diy/media/ad633a60-7dca-44c3-b425-e9616591e181.103467/full
https://www.diynot.com/diy/media/cf48d69e-99ad-444d-bb1e-b296fbb9ca5d.103466/full

and need to wire in the new timer (need to know which wires go where - im asuming its the same, and lose the red wire between L and 5)
https://www.diynot.com/diy/media/1f1eac84-ac16-400e-900b-ca33a651a752.103469/full
https://www.diynot.com/diy/media/209053be-8353-4802-848f-da4662cafcb2.103468/full

thank you in advance for any help... much appreciated
https://www.diynot.com/diy/media/1f1eac84-ac16-400e-900b-ca33a651a752.103469/full

 

[Atomix]

Hopefully these pics will help....

 

[EFLImpudence]

Yes, you are correct.

Same numbers, no link.

 

[Atomix]

Thanks,
I wired it in - using the above, but now the hot water appears not to come on, so thinking it may be the heating/water valve control...

 

[stem]

Was it working before you replaced the EP2000? If it was, then check that the yellow wire in terminal 3 of the Honeywell is secure.

If the hot water wasn't working before you replaced the EP2000 then the fault will be elsewhere.

As you have a wire connected to terminal 1, that indicates that you have a 3-Port motorised valve, in which case the valve is unlikely to be the problem. The 3-Port valve is pulled to the hot water position by a spring, so when they fail, that is normally the position that they fail in. In which case, it's the central heating that fails to operate.

First, I would start by checking that the hot water cylinder thermostat is working. With the programmer set to central heating 'off' and hot water 'on', turn the cylinder thermostat up and down slowly. When you turn it up, you should hear a click and the boiler / pump start, turn it down and you should hear a click and the boiler should go off. [If the system has a pump overrun the pump may continue, but the boiler should still go off] if this doesn't happen then there is a problem with the hot water cylinder thermostat or its associated wiring.

It's possible (but unlikely) that the motorised valve has seized in the central heating only position. Turn off the mains power to the heating system (not just at the programmer) and see if you can slide the manual lever at the side of the motorised valve to the 'manual' position and release it. It should return slowly to where it came from, if it does, it is returning to the hot water position OK.