New Tado installation, all working but...

trillyuk

Replaced Drayton wired thermostat and old controller with Tado Wireless V3+ along with 6 Smart Tado radiator valves. The boiler is a Grant 21E Oil boiler. The issue I have is the central heating pump is always on, the boiler however works when required, turning on and off as expected, just the water pump on 24*7.

I have a combi boiler so a simple setup and changed the configuration of the Tado controller to reflect a combi boiler. Only 4 wires to worry about in the controller, live, neutral, and then CH-COM and CH-NO. The old wired thermostat has been wired as instructed, so live (a black cable for me) to the "call" (grey cable) and neutral (blue) and earth both isolated.

I have reviewed the cabling and by disconnecting the old wired thermostat live and call cable the pump goes off after a couple of minutes, connect again and pump runs again.

Assuming the central heating pump is not meant to be on 24*7 any ideas what could be the issue or best to get a tradesperson in?

johnnyp78

Just to clarify, what tado device are you wiring into? If it’s a wireless receiver have you wired in the power source? Look at section 4 - switched live. If it’s a smart thermostat this doesn’t apply as it’s battery powered.

https://cdn.brandfolder.io/607DGEMS/as/tqh86npbjjhws5gwkxfncbfh/104172-DIGITAL-WRP01IB01-INSTALLER_MANUAL-TA-UK-00-V2.pdf

trillyuk

Thanks for reply Johnnyp. I now have a Tado wireless thermostat into wireless receiver.

So yes section 4 but the non switched version is what the install walked me through which seems correct as have 4 wires. If I don’t connect the live/call wires from the old thermostat then nothing works.
The old thermostat wiring is now wired according to section 3 in the manual.

trillyuk

Sorted. Its a quirk with the boiler (Grant 21e Oil Boiler) and how I read the Tado instructions.

Tado advise to have leave the heating on. On the boiler there is a switch with 2 options, "Constant" and "Timed". I had switched the boiler to Constant so its always on as I believed from the instructions that was what was needed . However, after checking all of the connections and everything is as it should be the only other thing that was changed was the Constant/Timed switch.

Flipped the switch to Timed and everything back to how it should be which is Tado sending demand signal and turning on both the central heating pump and boiler. In Constant the pump was always on but the boiler came on and off when needed.

Was just about to give up and get a professional in but glad its a simple solution, annoying took a while to sort!