HELP! Replacing EP2000 with Honeywell ST6400C

[pinzy]

Firstly I have gone through all the related posts and now more confused!! Has anyone attempted to do a similar replacement?

I have opened the EP2000 programmer and drawn the existing connections and also same with the white connection box near the 2 valves so I can go back if necessary!! I don't have the original wiring diagram for the EP2000.

I have deduced that I have a S-Plan open gravity system but the wiring diagram from Honeywell doesn't quite look like what I should have. For example the Orange wires from the zone valves connect to the Black going to the boiler (Potterton 80e)!

What's the best way to explain/show this?

ANY help is greatly appreciated.

 

[bab]

If my memory serve me right you should only have 4 main wires in that old programmer & possibly earth. is that correct.1st N then L then 3+4

 

[pinzy]

No, this one has a N block on the left and an Earth block on the right most. In between it has:

A, B, C, D, N, L, 1, 2, 3, 4, 5

A,B 1,2 and 5 don't have any wires connected.

I think this must be one of the first models from the 80's!!

 

[corgiman]

Why not pop and ep 2002 on it they are availible at all good plumb centres

 

[pinzy]

Yes I probably should have done that but I assumed that it would be a simple job so bought the Honeywell which I can't return.

 

[bab]

N & L is the neutral & live in from the power 3 is hot water on & 4 is htg on.

 

[pinzy]

Thanks bab...another question...I have typical Blue, Brown and Earth wires coming out of the Room thermostat and Cyl. Stat yet in the diagram I see 1,2,3 and 1,2,C. Which one would map to L, N and Earth?

Many thanks for your responses so far

 

[bab]

Thats not a good one to assume. the cylinder stat only requires live in & live out .NO NEUTRAL. normally C in & 1 out on S plan, the room stat though can have a nuetral to make it more responsive but not allways required. if the roomstat is electronic it will require a N to work. An eletronic roomstat wont click if turned up & down when there is no power to it. If urs clicks all the time it only needs live in & live out. Look in the back of the cover to the diagram. The best thing is to trace the wire which soundslike flex back to the wiring centre & see where the blue goes. (I WOULD GUESS that they have used blue 4 N Brown 4 L in & the earth live back to the brown on the htg zone valve but thats only an assumption

 

[pinzy]

Thanks again. I was confused as the earth wire from the room stat was connected to the Live and I have never seen that - but it makes sense.

Well it's too cold to attempt the change so I will wait for some warmer weather! If anyone comes across a wiring diagram for the EP2000 I would GREATLY appreciate it!!

 

[corgiman]

if you have not started yet I really really really recommend just buying a ep2002

as you can see re wiring one is a bit of a hassle even for those who know what we are doing!!

 

[pinzy]

does the ep2002 allow me to set CH and HW independently? I can always sell the Honeywell on eBay!!

 

[corgiman]

Yep it does

so does the 2000 you just have to change the sliders at the back

but be careful what kind of system to u have, if you have a gravity hot wter and pumped central heating you cannot have the heating on with out the hot water?

It might not be as easy as just changing you programmer to have your heating and hot water work independantly

 

[pinzy]

ahh didn't know that.

I do have a gravity system I think - boiler downstairs and hot water cylinder upstairs in loft. There is a pump for CH with 2 zone valves.

Does that mean I'll never be able to have CH and HW independent without replumbing?

 

[corgiman]

Yes it does really

 

[pinzy]

well thanks for that piece of vital info.