Danfoss 103 mechanical timer to FP75 programmer

[bjl]

im changing over the old danfoss 103 mechanical timer over to the danfoss FP75 programmer. It is a combi boiler so hot water side wont be used just wanted to check on wiring. The connections are

103 timer common terminal 3 linked to live
'on' terminal 1

FP75 programmer CH on terminal 4
CH off terminal 2

just to check where does cable on timer 103 terminal 1 'on' marked go on the programmer ?? CH on or off??

 

[tazz]

This programmer may not be suitable, as it has no dry relay contacts. The fp75 has only switch live outputs for CH and HW

 

[Johnmdc]

Connect it to terminal 4 CH on

 

[Leesparkykent]

Why use a twin channel programmer if you only need 1 channel?

 

[bjl]

i had this lying about. so on terminal1 is CH on ?

 

[Leesparkykent]

......

 

[tazz]

Connect it to terminal 4 CH on

Good tip on damaging his boiler......A combi requires dry contacts as already stated. Lee sparks has posted 2 diagrams, one for volt free timer (which is required) and one for the Danfross fp75 which has switch live. (which will not work)

 

[davesparks]

Good tip on damaging his boiler......A combi requires dry contacts as already stated. Lee sparks has posted 2 diagrams, one for volt free timer (which is required) and one for the Danfross fp75 which has switch live. (which will not work)

But the OP states that the live is linked to the common of the volt free switch on the existing programmer

 

[Johnmdc]

Good tip on damaging his boiler......A combi requires dry contacts as already stated. Lee sparks has posted 2 diagrams, one for volt free timer (which is required) and one for the Danfross fp75 which has switch live. (which will not work)

I don't know what you mean by "dry contacts" if you mean volt free then the OP already said that live was linked to common on the 103 which means the boiler is mains switched.
So not likely to damage the boiler at all!

 

[tazz]

I don`t know any combi which works on switch live, all I seen are volt free switching to timer then stat.
The op states this is a timer he has not what was fitted, so link was on backplate