S PLAN DIAGRAM ... confusing and wrongly drawn?

[diyhandyman]

I am a little puzzled by the S PLAN wiring diagram (as from Honeywell).

It, unlike the 3 port mid position type, doesn't make 100% sense!!

The cylinder stat 1 terminal is apparently supplied from the HW on at the programmer, and when under temp (60) is should make and put power on to the Brown wire (motor) of the 2 port mv, which then moves across and makes the permanent live (grey wire) close and put power on to the switched live (orange) which in turn make the pump and boiler live.

But the diagram is drawn badly, and according to the way it is drawn, how can 1 make C live, as the switch is the wrong way round.. if you see it you will get me. How can the programmer power (HW on) make the switch SUCK back to the 1 terminal of the cylinder stat?!! shouldn't it be the other way around or is it me looking at it wrong?

And on top of that, the cylinder stat I have says C is the common terminal, 1 is call and 2 is sat. Well, obviously for a 2 port the sat of the cylinder stat is not required, but 1 is call, and according to the honeywell diagram, 1 is the common terminal...

please help me as i am puzzled by this diagram!!!!!

 

[gas4you]

Wire HW on from programmer to C on cyl stat, then 1 on cyl stat back to the brown wire on the HW zone valve.

As the cyl stat is a basic on/off switch in this system it will not matter which terminal is actually used as common, 1 or C.

The rest is as you post.

 

[diyhandyman]

thanks for clearing thast up, i just wanted to be sure, and i was thinking the same. but the diagram (honeywell) isn't v clear is it!! it looks like the switch needs to be sucked back to make contact!! it ahould be the other way round for people to understand better!!!

the sat terminal on the cylinder stat (for a 2 port) is just left blank also isn't it.

 

[Paul Barker]

Correct. The reason it is required for Y plan is to provide power to the boiler when hot water is not required but heating is.

It baffles me that you find y plan simple and s plan complexed. The converse is true.

 

[doitall]

Looks simple to me.

Cylinder stat 1 = call

Cylinder stat C = brown zone valve

 

[diyhandyman]

i understand how it works, it's just if the diagram had been like this: c for the common and 1 the call, and the switch going in the other direction, it'd look clearer... it seems a little strange the way it is drawn!!

no c is not common, as the power from HW on is going to terminal 1 on the cyl stat,.... so it makes it harder to understand if you don;'t know it.

 

[diyhandyman]

just looking at it again - if the c and 1 were reversed and or the switch going from the c to the 1 then it would make more sense ... as power goes to 1 and the switch is attached to c, so it looks like the switch will have to be sucked into the 1 for the motor of the mv (brown wire) to get any power!!

 

[doitall]

The live from the programmer goes to 1 and the brown from the zone valve C.

Nothing hard or complicated.

 

[diyhandyman]

i know it's not complicated, but from the drawing it doesn't look or seem like it can work right.

The power from the HW on at the programmer goes to 1, correct??

and the switch is connected to the C (which then connects to the motor of the 2 port) correct?

so when power is supplied from the prog. to 1, how does the switch move down to make contact if it is attactched to C!!! it can't be sucked down!! there's no power to it!!

 

[Rob]

The live from the programmer goes to 1 and the brown from the zone valve C.

Nothing hard or complicated.

Surely that's wrong. ^^

C+1 make when stat is calling.

C+2 make when stat satisfied

 

[diyhandyman]

it's a 2port valve (s plan) system, the c 1 and 2 are only used on the cylinder stat for a 3 port mid ( y plan) !

 

[Rob]

Read AGAIN handyman. I never said anything about wiring. Just the operation of a cylinder stat.

 

[diyhandyman]

so why did you say the original post was not right .....

 

[Paul Barker]

If you spent aslong working on the system as you can bantering here you'd be sat at home with hot water.

 

[diyhandyman]

no need to get nasty is there !!!

i;ll fix it up in 10, no rush!!!