Replace a honeywell programmer with a danflos

Found 17th Jan
The issue i have is that for some reason when the heating is on the hot water appears to be on as well... should it be ?

If i press the Hot Water Button +1hr it comes on ok
If i press the central heating button +1hr the hot water comes on as well as heating and i cant switch off hot water option

So i thought i would replace the unit with an FP715Si
I used the wiring diagram in the booklet with the new programmer but i now find again if i press the Heating button the Hot water light comes on as well.

In addition it looked like on the old honeywell the HTG ON was connected to the N terminal
If i remove this from the N terminal which obviously also has the N cable it doesnt work at all

Now i don't know if its because this unit cant do hotwater without heating or if its just wired up wrong by previous owners ?
Can the Glo Worm boiler do this ?

Also should there not be a cable on number 2 of the new unit ? - HTG OFF ?
And would this be a pumped system or gravity system as there is a dip switch to change on the new programmer.. not sure what difference it will make.
Picture of wiring.. Note Yellow was on connection 7 on old unit but not shown in pic

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Original Poster

Is your 3 port valve faulty?

Also why didnt you get a Heating engineer or Electrician out to sort this.


Also why didnt you get a Heating engineer or Electrician out to sort this.

​he didn't want spend money on it probably.

or maybe he likes diy and is asking for a little help just. hope you get it sorted kiefer. sorry I can't help but I'm sure somewhere on Google you'll find your answer

Check if you have gravity hot water, pumped heating. If so that's how it's often wired.

Honeywell C plan might give you an idea on the wiring.

Original Poster

Yes your correct muddassarsardar / trilock.. i can always put it back as it was and call someone in for a few £100 later.

well it turns out that looking at a few posts on the web that there isn't always a HTG Off cable attached.

I have also changed the setting on the programmer to pump instead of gravity and its letting me do hot water or heating independently now. I just need to find a way to check if the hot water is actually only heating up when the button is on and not with the heating. Have to wait until its stone cold again now.

As for a pump or gravity.. i appear to have a unit on the pipe from the hot tank so i guess this is for hot water ?, or would you have one in the same place for heating



YHave to wait until its stone cold again now.

Or you could just run the hot water until its gone

Hope you get it sorted. I installed my own diverter system years ago as all the original boiler had was an on/off switch. Installed a honeywell thermostat, honeywell tank stat, Lifestyle programmer, lifestyle junction box and a honeywell three port valve. This was a long time ago but I remember there was a conflict when comparing all the instructions which I think was with the 3 port valve and the programmer. I think there are something like 27 wires going into the junction box so last thing you want is a conflict. I connected the easy ones first which was the boiler, pump and all the earth wires and then had a think about which wires the programmer connected to. Luckily it was right first time with everything working as it should and I think it was the programmer instructions that were incorrect.
Edited by: "Smartguy1" 17th Jan

Original Poster

also sorted, sparky over on an electricians forum confirmed what i had
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