Problems with conversion to Danfoss FP715si

[kevt296]

Hi there, can anyone help?

Am having problems replacing my switchmaster 400 programmer with a Danfoss FP715si. I have installed FP as per conversion wiring and whereas the hot water seems to work ok and boiler fires on and off as normal, I cannot get the heating to come on.

Term 1 wires on the sw 400 have been routed to term 4 on FP
Term 2 wires have been connected into a separate choc block connector. Term 3 => term 3
Term 4 on sw400 did not have any wires going into it. so nothing to connect to term 1 on the FP.

Can anyone help please?
Many thanks

 

[kevt296]

Hey
For anyone still reading this ??

No replies from Forum, (disappointed) but have spoke to Danfoss themselves - very useful chaps.

If I understand correctly, the Switchmaster 400 doesn't allow heating to operate individually separately from hot water, although the hot water only can be run on its own. So if heating is on, so is hot water.

Therefore, the hw off signal used to allow separate operation of both is not connected. If left as is, the gravity selection on the Danfoss programmer has to be used.
In order to get independent operation of each, I have to re-connect Hw off signal. Fortunately, I still have a spare wire in a 4 wire cable to connect from terminal 7 of the wiring centre to terminal 1 of the programmer.
This will allow me to use programmer in pumped mode and get individual outputs!

I will try this tonight and see if it works, fingers crossed!!

 

[kevt296]

Did what Mr. Danfoss said and sure enough, I now get independent control of heating and water. So, the hw off signal is required for this programmer. So nice to be digital and have better control of the heat and hw.

Only small prob now is that no matter what position I set bit switch no.1 to, I always get 3 off and on's?? I wanted only 2 off and on's. Not a major prob as simply do not use 3rd setting but out of interest, does anyone know if this is set a different way now and is bit switch 1 redundant on the FP715 si??