boiler still on when programer sliders are switched off

[D_Hailsham]

if number 4 in the programmer is connected to 2 in the wiring centre the programmer will probably be knackered as number 2 is the neutral block. I take it you have numbered the wiring centre from the left.

You will get a short between live and neutral when CH is ON. All this should do is blow a fuse.


Looking at the pic of the wiring centre there are definitely strange things going on! I was going to go through them one at a time and identify what they did, but have decided it would be better to start again!

You have an S Plan system so here is the "standard" wiring diagram:

View media item 72

It's probably best if you disconnect everything and start again. First you have to identify each wire, which is best done when they are disconnected, otherwise you can get strange results.

 

[northernscum]

thanks d hailshamfor your help.just a quick one regarding each wire,the way i tested with putting a low voltage power pack on the wire is that ok for finding each wire.so my programmer should still be ok then

 

[northernscum]

also only thing i dont get is the controller on the drawing, L,N,HTG,HW on mine has you have seen i have L,N,1,2,3,4,5, so on the diagram HW would go into ?sorry about this the rest i understand

 

[D_Hailsham]

just a quick one regarding each wire,the way i tested with putting a low voltage power pack on the wire is that ok for finding each wire.so my programmer should still be ok then

That shouldn't damage anything.

If you disconnect, say the wires to the HW stat, and join them together with a terminal block, you can find the other ends easily with a meter set to resistance as it will show approx 0 ohms.

Some of the wires are obvious, e.g the pump and the two motorized valves. The grey wire in the bottom of terminal 4 is the switched live to the boiler.

The wires which need identifying are: those connected to the room stat, cylinder stat and the programmer.

The diagram I posted shows the mains input going to the junction box, which then feeds the programmer L and N terminals. You may find that in you case the mains feed goes to the programmer, which then feeds the junction box. Either way round is OK.

The Potterton roomstat terminal numbers are different from the diagram; here's a key:

Diagram = Potterton

1 = 2
3 = 3
2 = 4

The cylinder stat should have only two wires (and possibly an earth). It does not matter which way round they are connected to the junction box.

 

[D_Hailsham]

also only thing i dont get is the controller on the drawing, L,N,HTG,HW on mine has you have seen i have L,N,1,2,3,4,5, so on the diagram HW would go into ?sorry about this the rest i understand

L and N are, I hope, obvious

HTG is Heating ON - terminal 4 on the Potterton
HW is Hot Water ON - terminal 3 on the Potterton.

You need to link terminal 5 to terminal L on the Potterton

 

[northernscum]

thanks guy's think i should be ok now,will post back though if i run into any probs.leaving it till tomorrow now when i get home from work.

 

[picasso]

want to use the timmer function but it does not make a difference.the lights come on and go off at the times set but if the room stat clicks in it still comes on./

as a neutral is connected to the ch on terminal when the timer switches to ch on the fuse should blow, as the op hasnt said anything about fuses blowing I reckon the timer is b0lloxed or the op isint giving the whole story.

 

[northernscum]

i can slide both the switches to the off postion on hw and ch,and it should stay off but if i turn the room stat around so it clicks the boiler still fires up,which it shouldn't.i discovered this by setting the timmer for both ch and hw to go off at 10pm,but when i went to toilet in middle of night heating was still on and further investigation reveals what i said it dont work the timmer function.hope that clears it up for you no fuses have blown

 

[GasNewb]

I'd suggest checking the cables again, you want to have the power from the CH ON to go to your STAT, then to your VALVE, then to the boiler. That way the thermostat wont opertate unless the clock is switched on first.

 

[northernscum]

just going to start checking all the cables again,but first thing i notice is that on the diagram the boiler has L,N,E when i look at mine it also has a black wire so where should that go,can i just put a choc bloc on it and not use it or does it need connecting to another terminal

 

[northernscum]

the black is not used just had a look.there was a few wires in the wrong terminals acording to the diagram.just turned it on,the only problem looks to be with the room stat and CH zone valve.it is a myson power extra with a power indicator and it seams to be on all the time even when i turn stat down it is not closing the valve

Untitled

• northernscum
• 11 Mar 2011
• 1

does this look correct

 

[GasNewb]

You want the live feed from the clock ch on to come to number 2 on your roomstat, from the switched out which appears to be number 3 on your roomstat to then go the live on your 2 port ch valve.

On your two port valve you should have 5 wires. Neutral and earth connect to neutral and earth in your wiring box, the live will the live feed from the roomstat, you will probably then have two cables left. These connect to the boiler. Take a look at the circuit diagram for your boiler to see what they are labelled as on the pcb.

Same applies with water by the way.

Hope that helps.

 

[northernscum]

thanks for the reply.when you say#3 on room stat to live on CH zone valve,do you mean motor open.because on the wiring guide thats what brown is.
permanent live=grey
switched live=orange
motor open=brown
neutral=blue
thats the vavle wiring guide and it matches the s plan diagram,its a myson power extra valve for the CH and has a neon indicator which illuminates when valve is open and off when closed.now at the moment it just stays on even when i turn down the stat which should close it,any idea's why

 

[GasNewb]

Im not familiar with your thermostat itself, but their all pretty much the same.

Yes from #3 on room stat to brown motor open on CH Zone valve.

Only thing i can think of is possible faulty switch or maybe still something to do with the wiring.

Does your stat have a rotary dial and does it click when you move the dial manually?

 

[northernscum]

its all up and running fine now.i got broke off when i was doing it yesterday and put a wire what has no power in it into the stat and left the one with power out ,found it has i checked again and it all works like it should.thanks all for your help.