just installed vaillant timeswitch (plug in 130).
Timer is working (clock) but only calls for heat when switch is in "on" position. As soon as I switch to the position "clock", heating immediately goes off.
Tappets are in correct position for calling for heat.
Boiler is EcoTec 831 plus, installed 4 years ago.
Any help is appreciated.

Bill, November 2013

Thanks for your reply toptrish. Timer is working fine.
This old guy (me) was in too big a hurry in setting the tappets and got them wrong. Your solutions saved the day. Once again, many thanks

Bill, December 2013

Are you sure the tappets are correct, try turning clock while rotary switch is at clock position to see if boiler fires up when it should be off,or is the rotary switch locating correctly at the clock position

toptrish, November 2013