Danfoss CP715si wiring to allow separate HW and CH timings

[Matt J]

Hi guys

Just had a CP715si fitted in replacement of our old original CP715.

We have a fully pumped system.

How do I get the new programmer to do separate HW and CH timings? Some one has told its a wire swap on the backplate?

I've attached a photo of the current wiring

Thanks

Matt

 

[EFLImpudence]

The wiring should be the same.

Is it set to Gravity system by mistake?

 

[Matt J]

The wiring should be the same.

Is it set to Gravity system by mistake?
View attachment 147917

I've checked and it's set to pumped. Should each terminal have a wire connected too it. As you can see in my photo Terminal2 doesn't have anything attached too it?


Matt

 

[EFLImpudence]

Both devices have exactly the same wiring diagrams.


Are both CH and HW on when only HW is called for AND when only CH is called for?

 

[Matt J]

Both devices have exactly the same wiring diagrams.


Are both CH and HW on when only HW is called for AND when only CH is called for?

That's correct. maybe I'm getting confused. I was under the impression you could physically set different times for HW and CH?

When the programmer is set to auto for both CH and HW they both come on at the times set regardless of if its called for. For example in the winter, the hotwater will go off at a certain time but so will the heating. I then have to go and override it to keep the heating on longer. Very frustrating.

 

[Matt J]

I must add, the old programmer never allowed separate timings either.

 

[fixitflav]

Hi guys

Just had a CP715si fitted in replacement of our old original CP715.

We have a fully pumped system.

How do I get the new programmer to do separate HW and CH timings? Some one has told its a wire swap on the backplate?

I've attached a photo of the current wiring

Thanks

Matt

Does the system allow separate HW and CH? That needs a mid-position valve or two 2-port valves. If you have an either/or 3-port valve you can have HW only or Hw + CH, but not CH only.

 

[EFLImpudence]

I then have to go and override it to keep the heating on longer. Very frustrating.

Do you mean that then CH works on its own?

 

[JohnD]

why did you choose the SI version? Was it going cheap?

You know what it does, don't you?

 

[Matt J]

why did you choose the SI version? Was it going cheap?

You know what it does, don't you?

The plumber i was using supplied it but when I questioned him about this he wasn't helpful and never returned to help.

 

[Matt J]

Does the system allow separate HW and CH? That needs a mid-position valve or two 2-port valves. If you have an either/or 3-port valve you can have HW only or Hw + CH, but not CH only.

I have a 3port valve fitted.

 

[stem]

The wires at the programmer are connected to where they would be expected to go if you have a standard 3-Port motorised valve as part of a Y Plan system. That would be N, L, 1, 3 & 4.........But, what the wires are connected to at their other end of course is unknown, as is the rest of the wiring.

Assuming yours is a standard 'Y Plan' it appears to me that there is a probably a fault somewhere else, in which case, you will probably need someone who is competent to use electrical test gear and understands how a 'Y Plan' system works and is wired to check it through bit by bit. This can be tricky, because not all plumbers will understand how the wiring works and not all electricians will understand how the 3-Port valve works.

To answer your earlier question, terminal 2 is virtually never used. Only a rare type of valve called a MoMo would use it [I've only ever seen one] and AFAIK that applies only to the two port version. I seem to remember that the three port MoMo doesn't use it either.

 

[fixitflav]

I have a 3port valve fitted.

How many wires does it have, and what colours? Then we can tell you whether lt's a mid-position valve or either/or.

 

[Matt J]

How many wires does it have, and what colours? Then we can tell you whether lt's a mid-position valve or either/or.

5 wires.... Blue, Green/Yellow, orange, grey, white

 

[fixitflav]

5 wires.... Blue, Green/Yellow, orange, grey, white

OK, so it's a mid-position valve. If the timer is wired correctly, you can have any combination of HW and/or CH.