Activating CH pump and Boiler from Wireless 3+ - using a contactor/relay

GouldVilla

My central heating system has a boiler and circulation pump (big old house and needs the pump).. The old thermostat system (comptherm q8) used a zone control output for the pump. One option I've seen people post here is to get the add on receiver... just wondered if anyone had tried using an AC contactor (or relay) to activate both pump and boiler?

My idea is basically to provide power to circuit to signal (A1-A2) poles of the contactor with using the NO pair on the Tado receiver to switch/energise the contactor.

I'd then put the signal cable for the boiler (that would normally go to the Tado) to the first switched pair on my contactor (L1-T1) and similarly take the live wire to the pump which is currently going through the computherm and connect that to L2-T2) to have the pump work to.

Questions:

1) has anyone set it up like this?

2) any issues people can see with it?

3) any better way to do it ?

thanks

Chris

wateroakley

@GouldVilla provided that your boiler, pump and valves stay within the power rating of the Tado wireless setup, why do you need a contactor? domestic boiler and pump settings are usually fused 3A and controller at ~1A. Documentation says your current controller setup maxes out at 6A and 1A for each of four valves. Without an explanation of your system, do you need 6 amp contact?

luteijn

I think the proposed set-up would work, but you probably want a little more 'intelligence' in there than just starting/stopping the pump and boiler in one go. Once the boiler is off, you probably should let the pump run a few minute more, especially as tado will try to 'modulate' the heat output from the boiler by running it for a bit, then stopping, then running it again.

Maybe use the tado relay as an input to (e.g.) an arduino, that controls separate relays for the pump and boiler. It could even use a sensor to keep pump running as long as the water it is pumping is 'warm'.