I have a Sunier Duval SD 620 combi boiler and have a Danfosse 103 timer ~ old but reliable ~ Im fitting a Danfosse RET230P Room Thermostat.
1. Im confused by the wiring or lack of wiring instructions ... does the thermostat wire directly into the Timer and ignore the boiler altogether as I presume?
2. ON THE THERMOSTAT~ It says to bridge 'L' and COM/3 thats pretty clear but then what???
What other connections need to be made and to where?
Thanks

Martin

Martin, July 2010

i have a oileer ISAR I IDEAL i wantnted to fit it with a danfoss time for the heater and hot water the
timer had
1 neutral
one live

can you instruct me how to procees

mohunlall, July 2014

Thanks Carefree ~appreciate you taking the time to answer.
The thermostat is a new install - until now I simply adjusted the temp dial on the boiler front. I thought it would make it more economical.
The boiler has a mains supply directly to it. Then there is the connection from the timer. I take it that means its a switched live 240v ?
The diagram for the thermostat can be found on the Danfoss site but it's thin on info.
Do the wires from the thermostat connect to the L + N on the Timer base plate or to the two wires on the opposite side of the timer plate that connect it to the boiler ?

Martin., July 2010

Not enough information to give a definitive answer, is the room thermostat a replacement or a new install?
The stat you are fitting requires three wired cable (that's 3 sheathed wires NOT twin and earth, effectively 4 core) as the stat requires a neutral to operate an internal relay.

A lot then depends on the boiler, is the switched live 240v or voltage free? I can't find a wiring diagram on that boiler to check. IF the boiler is voltage free, do NOT connect L&3 in the room stat as it will potential 'blow' the boiler circuits, also, if it is voltage free, the cable needed becomes 5 core (4 and earth).

Sorry to seem so random, but more information is needed to answer correctly.

In any case work safely when dealing with system electrics, ensure correct isolation.

Carefree, July 2010