Replaced programmer, boiler always on

[berkstom]

Hi. I have replced a Danfoss Set 5 programmer with a Danfoss FP715. I followed (I thought) the wiring conversions with the instructions, but as soon as I turn on the power, the boiler fires up, even if the programmer is set to off. The boiler turns off after about 5 minutes (I assume when the water is hot), but I cannot turn it off. I have looked at the wiring diagrams again, and I think I may have connected the Boiler Live wire incorrectly. It is connected to the L terminal of the Programmer. Does anyone know where I have gone wrong?

 

[gas4you]

The L terminal of this programmer is for the live feed into the programmer. Your boiler should be controlled from any 3 port or 2 port valves you may have installed.

Terminal 4 on the Danfoss is heating on, terminal 1 is water on and terminal 2 is water off. (1 and 2 might be other way round ) Wiring diagrams should clear the confusion

 

[berkstom]

OK thanks, so at least I know now where my problem is! (I am assuming the flexible cable in the wall box is the boiler - all of the others are solid copper). Now all I have to do is identify which of the wires is from the valve. This is an existing system, all I have replced is the programmer, so the cables are already there. Is there a convention as to which core colour goes where - the system is about 12 years old, and there are red and yellow cables.

 

[gas4you]

What motorised zone valve do you have if any? Do you have a room stat?

 

[berkstom]

I have not found a zone valve, but there is a room stat in the living room. There is also a stat on the cylinder. Many thanks for your help.

 

[gas4you]

I would think that if there is a cyl stat then you must have a zone valve somewhere

Is it a fully pumped system or gravity primary, 2 or 4 pipes off boiler?

Room stat is usually red live in, yellow switched live out to valve/boiler, blue neutral, may or maynot be an earth.

Cyl stat, basic 2 wire is common live in, terminal 1 switched live out.

I would expect that terminal 4 on 715 goes red to room stat and yellow goes to zone valve motor or boiler live & pump.

 

[berkstom]

I'll tak a close look tomorrow. Thanks for your help.

 

[berkstom]

Traced the "live" from the zone valve, connected to boiler live, and now works perfectly! Thank you for your help.