C27 programer

[paul26]

HI Guys,
I bought a new house and wanted to change the old time clock on the boiler to a c27 programer so I could have different settings for each day. There are no thermostats on the system just a 2 port valve which I think is a spring return.
The boiler fires when I turn on the HW channel and the valve opens when I turn on the CH channel or at least is supposed too.
The valve opened and all the radiators worked before I changed the programmer, so I must have the wiring wrong, although it seems straight forward as I both programmers said HW on, HW off and so on.
Heres the way I connected it

terminal L - mains live
terminal N- All neutrals from valve,boiler and mains
terminal 1-not used (HW off)
terminal 2- not used(CH off)
terminal 3- live to boiler(HW on)
terminal 4- live to valve(CH on)

Anyone have anys ideas any help would be great!

 

[ScrewForumIsJunk]

The wiring that you describe is completely wrong.

It shoud be S-Plan. There should be 2 x 2 port valves or one 3-port valve, If it has a spring return then it is a 2-port. Something odd there for starters.

It is also most odd that you have no stats at all! Was the system installed by an ex-coal miner?

For S-Plan -

Basically HW-ON drives the HW 2-port valve via the room stat and the CH-ON drives the CH 2-port valve via the cylinder stat. The contacts of the CH and CW 2-port vales are the ones that are wired-Or'ed and sent to the boiler/pump to fire up.

Quite simple really. I have C27 here at home.

 

[vernerbongo2]

The wiring that you describe is completely wrong.

I agree, have you explained it right?
were you able to control heating and central heating separately with the old clock?
My system has 2 two port valves also

 

[weepin dog]

was your old heating, gravity hot water + pumped central heating ?
if it is you may have to remove small link in the back of programmer.
hw on fires up boiler only.
ch on fires up boiler + pump (if ch on the hw is also on)

 

[paul26]

The system is fully pumped worchester bosch oil boiler, before I changed the clock the HW had to be swicthed on to fire the boiler, CH on its own did nothing , only open the valve to the radiators, there are no thermostats at all only trv's, the HW also heats the bathroom radiator. The system was installed 7 years ago because I got a certificate for a 10 year guarantee

 

[333rocky333]

If you still have it
Retry the old time clock, to see if system still works ok

 

[vernerbongo2]

yes I see were your coming from, the pump (which you never mentioned)circulates the hw all the time and ch works through the motorised valve when ch switched on.
your wiring looks ok, you should just have to keep your hw switched on as well as your ch to get the radiators to work. (in theory)
if not just fiddle about with the wires a bit, trial and error

 

[paul26]

Thanks Guys, I'll try the old time clock, It could be a coincidence that the valve give up at the same time.