Strange programmer wallplate wiring - no HW

[Mattt]

Hello,

Hopefully someone might be able to assist me!

I've been playing around with my new Tado (smart thermostat) system and have noticed something odd that the HW turns the CH on but doesn't heat any water.


I recently moved into the house and the previous owners just ran the HW off the immersion heater (pressurised hot water tank upstairs) - but the CH off the oil boiler.


I then started investigating and found the wiring on the controller wall plate looks odd:

(Picture deleted as it denied me posting - will try below)

There's a 3 core and a 4 core wire running to the wall plate - the 3 core has only the L connected and the E/N tucked away. The 4 core is wired corrected to the N/L but then the 2 black wires are connected to HW ON and CH ON - with nothing to the OFF terminals.


There is also a wired thermostat elsewhere in the house, which just has 2 wires connected.


Does anyone have any idea what's going on?

 

[Riley]

Welcome along, Post some pictures via Dropbox and we'll try an decipher it for you

 

[Mattt]

It's not letting me post up a link to the picture unfortunately!

Essentially the wallplate looks like below (numbers of wires in each terminal written below):

N L 1 2 3 4
1 2 0 0 1 1

 

[rpm]

Welcome to the forum Matt.
Good people here to help you.

 

[Mattt]

Here's a Dropbox link: https://www.dropbox.com/sh/vy945kdkf4lz57a/AAArpy3yKoD7NqyR2cvKrx1ha?dl=0

 

[Mattt]

Thanks for the welcomes 🙂

 

[stevetheplumber]

you only need the off terminal if your using a three port motorised valve as you say you haver a mains pressure hwc i would assume you have two two port motorised valves so the wiring you have sounds correct

 

[PETE 123]

Live to power on valve, will shut when no power on its own under sprint tension

 

[Mattt]

Thanks, it's a Trianco Contractor boiler.

It was serviced 3 months ago, so a bit puzzled as to what's going on. I recently replaced the old Drayton Tempus 7 controller with the Tado extension kit but the wiring is identical for both.

 

[jtsplumbing]

This is the wiring into the timer, have you found the main wiring centre that everything go's into [valves - stats etc.]

 

[Mattt]

Would that be upstairs with the HW cylinder? If so will take a picture later when at home

 

[jtsplumbing]

Would that be upstairs with the HW cylinder? If so will take a picture later when at home

That's the first place to look, what is the large white box at the top right hand side of 3td picture

 

[Mattt]

That's the Tado extension kit which was a straight swap for the existing Drayton Tempus 7.

i spoke to Tado today and they need to know what kind of system it is so they can set it accordingly so will check tonight.

thanks

 

[Mattt]

I've updated the Dropbox folder with more pictures

 

[jtsplumbing]

Can you trace the black wire from the Diverter Valve in the cylinder cupboard ? its not very long so wiring box maybe under floor, You need to top up water pressure a little ! (1.2Bar) looking a little low (.5bar)

 

[Mattt]

It goes into a junction box, can't see where from there.

How do I increase the pressure?

 

[jtsplumbing]

It goes into a junction box, can't see where from there.

How do I increase the pressure?

The chrome fexi pipe has 2 black leavers , open one fully , then gently open other keep eye on gauge until black pointer is inline with red marker then make sure you turn off both taps

 

[Mattt]

I increased the pressure yesterday morning to the line, I noticed throughout the day it dropped back towards 0.8 but then yesterday evening had increased to just above the marker.

is that normal?

 

[jtsplumbing]

Yes, best to check pressure when system is cold, [1 to 1.5 bar] black needle will rise as system heats up, did you not have any instructions left about system ?

 

[Mattt]

No instructions left for anything!

 

[jtsplumbing]

Better to go on-line and download instructions will tell you everything you need to know.