Programmer and Thermostat wiring issue

[BrewinStuff]

I've got a Danfoss programmer and Drayton digital SCR Wireless controller but no matter what I look at I can't see how to wire them correctly: the heating and hot water work, but appears to be on continuously rather that switched on demand for HW and by the thermostat for CH.

Attached is the current wiring setup but it's clearly not correct. And I can't see why there's a chocolate block connector in there either?! Anyone got any suggestions?

 

[AndyPRK]

You still need the timer to do the HW.
It’s that black wire in the timer.

 

[RandomGrinch]

It appears as if the wiring could operate correctly, depending on how the system is wired at the wiring centre.

The Grey wire in terminal 4 of the programmer controls the heating, this is linked into the SCR receiver, that sends a switched live out on the blue wire (SCR terminal 3), when there is a call for heat.

As mentioned above, the black wire in terminal 3 of the programmer controls the HW. This is linked through the terminal block, to provide a switched live on the brown wire.

Is this system new to you, and has it always been a problem?
Can we have a photo of the wiring in your wiring centre?

These sort of issues are usually related to a faulty programmer, or zone valve/s.

 

[ericmark]

We have a number of standard ways to wire central heating (CH) and domestic hot water (DHW) these plans were designed by Honeywell, and most seem to follow these plans.
C Plan basic no motorised valves, it decides if CH or DHW by turning pump on/off, no thermostat on DHW.
C Plan enhanced by adding a thermostat to the DHW in summer, it can be left running.
C Plan extra enhanced, adding a motorised valve, it can have domestic hot water cooler than central heating water.
W Plan a three port valve, to give DHW priority over CH mainly used with combi boilers.
Y Plan a three port valve with centre position allows independent control of CH and DHW defaults to DHW to help cool boiler.
S Plan two or more motorised valves allows the central heating to be split into zones.

Use of programmable TRV heads also allows splitting into zones.

In the main today, the boiler has a direct feed so it can cool down, and the supply to thermostats and motorised valve comes from the boiler, and it can be low voltage (230 volt) extra low voltage (24 volt) with on/off control, or variable voltage, and it controls the boilers' modulation (reducing output) the options vary depending on the system or plan in use, or combination of plans.

The pictures you show look like a S Plan, but this is a guess. The basic idea is the programmer selects the time on/off, and sends the signal to the thermostats CH and DHW which in turn control the motorised valves, and micro switches in the valves control the boiler, sometimes the micro switches in the motorised valves stick in the on position, but there is an indicator on most valves to show if open/closed etc.

But with so many variables, to try to work out what is wrong is near impossible without more information as to what system you have.

 

[BrewinStuff]

It appears as if the wiring could operate correctly, depending on how the system is wired at the wiring centre.

The Grey wire in terminal 4 of the programmer controls the heating, this is linked into the SCR receiver, that sends a switched live out on the blue wire (SCR terminal 3), when there is a call for heat.

As mentioned above, the black wire in terminal 3 of the programmer controls the HW. This is linked through the terminal block, to provide a switched live on the brown wire.

Is this system new to you, and has it always been a problem?
Can we have a photo of the wiring in your wiring centre?

These sort of issues are usually related to a faulty programmer, or zone valve/s.

Is this what you need? It's hard to see as the panel is trapped by a replacement valve the plumber fitted when he serviced the boiler a month or so ago.

The system isn't new, but we've been renovating so haven't been using it for the last 2 years.

 

[BrewinStuff]

We have a number of standard ways to wire central heating (CH) and domestic hot water (DHW) these plans were designed by Honeywell, and most seem to follow these plans.
C Plan basic no motorised valves, it decides if CH or DHW by turning pump on/off, no thermostat on DHW.
C Plan enhanced by adding a thermostat to the DHW in summer, it can be left running.
C Plan extra enhanced, adding a motorised valve, it can have domestic hot water cooler than central heating water.
W Plan a three port valve, to give DHW priority over CH mainly used with combi boilers.
Y Plan a three port valve with centre position allows independent control of CH and DHW defaults to DHW to help cool boiler.
S Plan two or more motorised valves allows the central heating to be split into zones.

Use of programmable TRV heads also allows splitting into zones.

In the main today, the boiler has a direct feed so it can cool down, and the supply to thermostats and motorised valve comes from the boiler, and it can be low voltage (230 volt) extra low voltage (24 volt) with on/off control, or variable voltage, and it controls the boilers' modulation (reducing output) the options vary depending on the system or plan in use, or combination of plans.

The pictures you show look like a S Plan, but this is a guess. The basic idea is the programmer selects the time on/off, and sends the signal to the thermostats CH and DHW which in turn control the motorised valves, and micro switches in the valves control the boiler, sometimes the micro switches in the motorised valves stick in the on position, but there is an indicator on most valves to show if open/closed etc.

But with so many variables, to try to work out what is wrong is near impossible without more information as to what system you have.

We are on oil with a Warmflow boiler (pictured). I think it's just pump on/off so maybe C plan basic? I'd usually call the plumber as boilers are black magic to me, and this wouldn't be such an issue. Unfortunately I can't get someone with Christmas so close, and I'm deploying with the military for six months at the start of Jan and leaving my wife on her own with heating on the blink!!

 

[ericmark]

When I bought this house, I found to turn on heating I had to switch on at the programmer then go outside down a set of steps into the garage below the house and plug in a pump.

I really could not believe the previous owners had been doing that, think they used the open fire instead.

I found tracing was not easy, but seems one core had been lost in the cable from main house to garage, and I used a Nest Gen 3 thermostat mainly as it allowed full control with only 2 wires (plus earth) but plumbing was not my scene, so got the local central heating guy who said don't know how to wire that, which for me was not a problem I did, but I had not expected him to say that, wonder what other house owners do?

Likewise, I am also on oil, but looking at yours I would guess W Plan and it is a combi boiler. If it were mine, step one is note details and try and find the manual online,

I have found a random set of instructions here not sure if your boiler? I will guess this

is the wiring diagram together with this
I will guess this

is what this relates to? Look at page 49 on, does it seem to relate to your boiler?