Tado V3 pump over run?

Tac12

I am very happy with my V3+ system. I started by replacing my old Honeywell wall thermostat with Tado wired thermostat. My system is a classic 90’s Y system with Honeywell 3-way valve and programmer I set hot water times via the Honeywell, and CH to constant and let Tado do its thing. Everything is basically as it was installed in 1995, but along the way programmers pumps and boiler have replaced. I have (especially when Tado have a sale) added more radiator valves and wireless room thermostats. I now have full control of every room each with its own wireless thermostat. All works beautifully with any room able to demand the boiler to fire. Temperature control in all rooms is perfect 21 +/- 0.2. I never bothered to install the boiler control although it came in the kit. The issue I have now very occasionally is when there is a transition from HW+CH to CH the programmer send a signal to the boiler not to fire momentarily cuts power to the pump, then starts the pump and send a signal to the boiler. All fine except occasionally I get a momentary kettling. Not always and I’m not 💯 sure if there is a specific sequence of events that triggers this condition. So to get to question should I have some sort of pump overrun? If so how is this best achieved? Is this present in the Tado V3 hot water controller?

hugbilly

Most modern boilers include the ability to overrun the pump themselves and to achieve this the pump is fed via the boiler rather than direct from the mid position valve. Before we replaced our Ideal Classic with a modern Greenstar we had quite a kettling problem, mostly due to the heat exchanger being furred up I think.

In order to, partly, improve things I fitted a delay off timer. It was a bit of a fiddle to fit, it needed its own permanent live feed, but it worked pretty well and did lessen the kettling.

The delay off timer I used was this one:

https://tinyurl.com/y424e9vx

wateroakley

Hello @Tac12 Weclome. Thank you for describing your happy experiences. Pump over-run is usually an internal boiler function. There are so many Tado options and settings, that would interact with the boiler internals, it's hard to say what would help. Our experience with Tado (and the boiler) is 'suck it and see'.

Tac12

I’ve made some observations that my kettling occurs when my wired thermostat relay “clicks” when it gets to set point (21). As a kludge I’m now trying setting it to 23. All my rooms have both TADO TRV and wireless thermostat. The location of the Wired Thermostat is in a short section of unheated hallway between the kitchen and the hall. An alternative would be to set at a low temperature and rely on the room thermostats to fire the boiler.