New CH and HW install - issue with CH control

Options

Hello,

I've installed a Tado V3+ Heating & Hot Water Wireless Smart Thermostat Starter Kit for my partner and struggling to get it to work.

It's on a Y/S Plan setup. The old programmer was a Drayton Tempus 6, with a Honeywell RTS1 Thermostat. There's an Ideal FF-350 classic boiler providing CH and Hot Water to a Megoflo tank which has an electric immersion heater.

I've bridged the thermostat and fitted the new Tado controller/extension. I'm certain that the bridging is correct and pretty certain that the controller wiring is also correct:

However, I'm experiencing problems in getting the system to work correctly. The boiler is cycling on and off every two minutes or so constantly irrelevant to what is set on the app. Not sure if the Hot water control is working to schedule or constantly on when the CH is on, but we are getting hot water. The only way to stop the heating is to switch off the boiler.

Anyone got any advice on how to resolve this??

Answers

  • wateroakley
    Options

    Assuming the wiring and setup is correct, the top suspect would be faulty vintage (circa 2003 ?) motorised valves. There are three red wires on your 'original' and 'after' piccies? - suggests that you double-check that your CH NO red lead (that calls for heat to the motorised valve) has not been inadvertently swapped onto the permanant live?

    Something is calling for heat. Starting logically from Scheduler/app - Room Thermostat - Controller - Zone valve - Boiler. Both HW and Heating lights are 'on' in your piccie, calling for heat?

    You should work through the logic and electrical chain. Is HW or CH calling for heat in the app and controller, or OFF? Check the controller lights do as expected from the app scheduler and room stat settings. Check power safely (with an electrical screwdriver or tester): Is there power at the NC or NO terminals? 'Call for heat' should have power at NO, and no power at NC. When OFF, power should be at NC and no power at NO. If NO/NC power at the controller is as expected, that should point you at a fault outside of Tado and e.g. start lookig at the motorised valve(s).

    If you are in any way uncertain or unsure of electrical competence, consult a qualiifed professional.

  • zippydoda
    Options

    Is there any way to see if the controller is calling for heat but the request not being received by the boiler?

  • wateroakley
    wateroakley ✭✭✭
    edited November 2023
    Options

    The two RH lights on your wireless controller show ‘Call for heat’ from CH and HW. Check the zone valves by moving the manual levers on the short side of zone valve. They are spring loaded. If the valve is ‘open’ they are easy to move to the right or already there. If the valve is closed, the lever is harder to move to the right.