Replacing Mechanical timer for HW with Tado

laxity

I currently am using Tado receiver which has both Heating and Hot Water control. When I installed this I learnt that connecting the Hot Water control wasn't possible as we have a Gledhill A-Class BoilerMate SP Thermal Store.

I am now revisting this again as I am wondering if it would be possible to by-pass the mechanical clock timer on the Thermal Store and wire it into the Tado HW receiver terminals. As the mechanical clock only acts as an ON/OFF switch I was thinking that surely the Tado receiver would be able to perform this task instead.

However, I have some concerns about if this is possible due to the voltages involved and my lack of knowledge of what the terminals do in the Tado Receiver and the Mechanical Clock. Below is currently how I have my Tado wired for just heating :

I see on the labelling max 230V~3(1)A / max 30V = 3(1)A.
Does this mean that CH works with 230V and the HW works on max 30V?

Here is the Thermal Store and the back of the Mechanical Clock :

Firstly I am guessing that the first pair of terminals are for the CH Timer on the Thermal Store when set to TIMER mode (it is set to constant for Tado use) AND the second pair of terminals are for the HW Timer. Not sure which is which or why one set has a spare 3rd terminal.

Now the first thing I noticed is that both appear to be in the 240V range. Does this mean that I can't just wire this into the HW terminals of the Tado receiver due to it being 30V max?

If it were possible, which of the two clock terminals would be wired up to the Tado HW terminals ("HW NC" "HW NO" "HW COM") ? I am not sure what those mean.

Anyone know if this is feasible ?

Thanks!

wateroakley

@laxity Hello. Presumably the second picture is the rear of the timer? This appears to be the connections for an Analogue 7-day timeswitch. If you are not sure what the electrical symbols mean, best to engage a suitably qualifed professional.

The thermal store installation manual does not provide any elecrical ratings. However, it does show it has an immersion heater, probably drawing a current of 13 or 16 Amp?

Looking at the connections and symbols in the pictures:

• Timer: 1 and 2 will (probably) be the clock motor (220-240 Volt, 50 Hertz AC).
• Timer: The switch contacts are (probably) 3 4 & 5. 3=COM, 4=NO, 5=NC. The switch is rated at 16 Amp for a resistive load (or 8A for an inductive load) at 250 Volt AC.
• Tado: The wireless receiver will switch (up to) 3 Amp resitive load at 230V AC (or 1 Amp inductive). Or (up to) 3 Amp at (maximum) 30 V DC.

Therefore, Tado is not going to handle the current (Amps) and load (Power) that the mechanical timer can.

A solution will need a contactor that can handle a 16 Amp current and 4kW load, eg Salus? solid state switch, to interface between the Tado receiver connections and the timer connections.

Best to engage a suitably qualifed and experienced professional who can look at what is installed, how it is wired, and provide a solution.

Jonahs8

https://eco-outlet.co.uk/products/ce-rm-16a-relay-module?variant=43428816126188&country=GB&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&srsltid=AfmBOoqARyglzuIpwIfFw7giQUSpusFCNVEWAKfHvMpXPi8u7LYsBpQb5Ok&gQT=1

BUT PLEASE! seek a qualified electrician for help / installation.