Drayton RF701 - only 3 wires

[gavinallen50]

I'm trying to replace an old Honeywell thermostat with a new Drayton RF701 receiver. Unfortunately the old one has three input wires, while the new seems to need four.

There is a note in the wiring instructions, but this is only referenced from the Zone Control diagram not the Combi Boiler diagram.

Note: If the Digistat +2RF or +3RF is used without a separate
programmer, or the programmer is set constantly on it would be
acceptable to link ‘L’ to ‘1’ provided the output voltage required
is 230V ac.

I plan to leave the boiler programmer permanently switched on (like it says), but I'm not sure what it means about the 230V output voltage.

Any advice would be appreciated before I give up and get someone in to install it for me.

Thanks.

 

[jtsplumbing]

You need to be careful that you don't put 240v from stat into low voltage connections on PCB in boiler, What boiler are you trying to link to ??

 

[gavinallen50]

Thanks for the reply.

It is a Vaillant ecotec plus 824

 

[stevetheplumber]

you need to know if the existing wiring is 240 or24 volt you can meter at the stat to confirm

 

[stevetheplumber]

you need live and neutral to power the reciever the switch terminals are isolated and can be used for either 24v or 240 what they refer to is using a loop from the live to common to give you 240 across the isolated terminals but you need to check which volage the existing stat is running on as vailants can be eitherif you put 240 into the 24v terminals you will need a new board@ 250plus

 

[jtsplumbing]

Same as Steve is pointing out, you have to be careful what terminals you connect to on boiler, one will require a live link the other is what they call volt free, and can be an expensive repair if you get it wrong, just call someone out to do it, if easy access about 1hrs work

 

[gavinallen50]

Thanks for the advice...I'll get someone to do it for me.

 

[gavinallen50]

Sorry, I've been thinking about this again.

If the old thermostat only has live, neutral and the switched output then surely the boiler is able to cope with whatever voltage the live is running at. By joining the live and common in the new thermostat I'll have effectively the same circuit as the old one - the thermostat switches on by connecting love to the output.

I'll still probably get someone to do it for me, I just like to know how things work.

Thanks.

 

[jtsplumbing]

You will need LN & maybe E to supply receiver, and then common & SL to & from boiler, so min 4 wires or maybe 5. look at wiring for boiler and what they connect to

 

[Dotty]

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