Worcester 35CDi and Honeywell CM67 connection issues

I've got a Worcester 35CDi (condensing combination boiler). I've recently bought a programable timer - a Honeywell CM67.

With the CM67, there is a R6660D box which connects directly to the boiler.

I have these instructions from the boiler:

  1. Remove Link
  2. Connect room thermostat LIVE supply to terminal (Ls)
  3. Connect room thermostat Live return to terminal (Lr)
  4. Connect room thermostat NEUTRAL to terminal (Ns)

But on the R6660D box, there is no indication which is the LIVE supply, LIVE return or NEUTRAL.

The instruction with the CM67 comes with a wiring diagram. On the wiring diagram there are only 2 links comming from the boiler to the R6660D box.

Any help would be gratefully received.

Thanks, Bob

Reply to
Bob Parmar
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I've got a Worcester 35CDi (condensing combination boiler). I've recently bought a programable timer - a Honeywell CM67.

With the CM67, there is a R6660D box which connects directly to the boiler.

I have these instructions from the boiler:

  1. Remove Link
  2. Connect room thermostat LIVE supply to terminal (Ls)
  3. Connect room thermostat Live return to terminal (Lr)
  4. Connect room thermostat NEUTRAL to terminal (Ns)

But on the R6660D box, there is no indication which is the LIVE supply, LIVE return or NEUTRAL.

The instruction with the CM67 comes with a wiring diagram. On the wiring diagram there are only 2 links comming from the boiler to the R6660D box.

Any help would be gratefully received.

Thanks, Bob

Reply to
Bob Parmar

The neutral is only needed on old mechanical (bi-metal) thermostats with an accelerator heater.

Treat the thermostat as a simple switch needing only a live feed and a switched (demand) return.

Reply to
John

Currently the link your supposed to remove is between the Ls and Lr? If so then the Ls and Lr are the ones to connect to the R666OD.

The neutral and earth could also usefully be taken from the boiler, the Ls would also be the live for the R666OD. 4 core and earth cable would make a neat job of it. In any event the R666OD should be electricaly isolated by the same switch that isolates the rest of the boiler/central heating.

Reply to
marble

The instruction leaflet at

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that

A on the R6660D Live supply (Ls) on the boiler (No.2) B on the R6660D Live return (Lr) on the boiler (No.3)

Diagram b on page 5 applies if you power the relay box via a separate mains supply. You do not need to connect Ns to the relay box (No.4) if this is what you are doing. You probably can supply the relay box with power from the boiler if this is better for you but some more connections need to be made.

Reply to
John Phillips

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