Hi we have a Baxi Combi 105E and a SUNVIC Select 107 timer switch we just cannot seem to get them to work together in particular with trying to get the timer just to put the heating on and off. If we have the boiler switch to hw/radiator mode the timer just keeps the heating on continuous.

would really appreciate some help with this one.

Thanks

Jo

Jo, October 2008

oh and check he's removed the small link wire from between t1 and t2 on boiler

iain, October 2008

them boilers can develop a fault like that but since its like that from installation i would check wiring.

boiler:
live
neutral
earth
t1 ------ power from boiler to timeswitch
t2 ------ power back from timeswitch or room stat if fitted

timeswitch:
live
neutral (bits that keep everything remembered etc)
common (1) connection from t1 on boiler
con (2) ch off (not used)
con (3) switched live out to t2 on boiler

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if room stat is fitted it will lie between con (3) on timeswitch and t2 on boiler.
so con (3) from timeswitch would connect to common on room stat and calling from room stat would wire back to t2 on boiler
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iain, October 2008

Yes it has been like this since installation, just put up with it and turned it on/off manually...... Did have problems with the original electrician who should have fitted the timer and had to get one of our own to do it, will get other half to have a look at your suggestion. good job I'm a horder and keep all instructions etc....

Thanks for your advise.

Jo

Jo, October 2008

has it been like this since installation?

boiler on ch+hw

connections in boiler should be live neutral earth, term1 on boiler should be wired to common 1, on time switch and number 3 on time switch should be wired back to terminal 2 on boiler (via room stat if fitted).

if you only have boiler, timeswitch and maybe roomstat, turn power off and remove wiring from term 1+2 on boiler to find out if its the timeswitch wired wrong or at fault

iain, October 2008