Potterton EP2002, PR2 to Tado Wireless starter kit v3+

6 May 2022
Reaction score
United Kingdom
Hi All,

I hope someone can give me some guidance on replacing my current thermostat and programmer with Tado.

Boiler: Potterton Suprima 40L
Programmer: Potterton EP2002
Thermostat: EP2

I have a gravity fed system with tank in attic, hot water cylinder/ radiator pump and shower pump in separate closet on 1st floor hallway. As it stands heating only works of hot water is on- hopefully both can be controlled separately…



  • DB635D9A-727E-4FE4-9715-D5F30863149B.jpeg
    233 KB · Views: 146
Sponsored Links
That will depend upon the type of plumbing set up that you have. Not all systems will allow separate control without changes to the plumbing. You will need either a 3 port motorised valve, or two or more 2 port motorised valves.

The photo of the EP2002 you posted shows a wire connected to terminal 1 which is 'hot water off' that suggests that you have a 3 port motorised valve installed. However there is a problem. If that is the case, you should already be able to have separate control of the heating and hot water and if you don't there is something wrong elsewhere; in which case I would suggest that you get someone to get the system working properly in its current state first, before attempting to change the controls.

If you have a 3 port valve, it is responsible for starting the boiler and pump when only the heating is required, so the failure of that to happen could indicate a problem with the motorised valve. Something like this is what you are looking for:

Hi Stem,

Thanks for your response!

Yeah, there is a 3 port valve in the airing cupboard- how can I test if it’s working fine?

I recently had the hot water pump changed for the radiators.
Sponsored Links
Thanks Mister Banks. I’m not an expert in plumbing but is it a Y-Plan heating system?
I have a gravity fed system with tank in attic
That is indeed a gravity fed system. Some confuse 'gravity fed' with 'gravity circulation' which is something totally different, and which you don't have.

is it a Y-Plan heating system?
Yes it's a fully pumped Y Plan.

I recently had the hot water pump changed for the radiators.
It's for the hot water too. It sends water to the 3 Port valve centre pipe and one of the outside pipes goes to the radiators and the other to the hot water cylinder.

how can I test if it’s working fine?

Its not easy. To do it properly you would need to understand how it works and be able to use a multimeter.

On the EP2002 programmer when switching the CH on, the HW also moves to on. And when you switch the HW off and leave the CH on the boiler switches off.

I was hoping to install the Tado kit to allow better control of heating system!

I appreciate the time and knowledge!
In that case all may be well. The EP2002 is probably set to 'pumped' central heating & 'gravity' circulation of hot water, if it is, then setting it to 'fully pumped' may solve your problem. It tells you how to do it on the back.

Last edited:
Thanks Stem. I’m struggling to get the panel off again, seems like it’s been pried too much and I can’t detach it!
Thanks Stem.

You were right in changing the mode to fully pumped allows me to have CH on without HW.

Much Appreciated!

How would I wire the Tado wireless receiver?l to the boiler?

The Tado doesnt control the boiler, it controls the mid position valve, the mid position valve tells the boiler when to come on and go off, as @CBW sats best to situate the receiver next to the wiring centre if you have one , the EP2002 programmer could double up as a wiring centre so you might not actaully have one
Prefect. Thanks Guys!

I will replace the EP2002 with the Tado wireless Extension.

As per the Tado instructions for Y-Plan I think this would be the wiring from the EP to Tado:

- L to L
- N to N
- 1 to HW NO
- 3 to CH NO
- 4 to CH NC
- 5 can be discarded
- bridge L to CH COM
- bridge CH COM to HW COM

Is this correct or how would I cable?

Much appreciated
not often I disagree with @stem but you have A Y plan OPEN VENT system nothing gravity about it

Not sure we are disagreeing, I think maybe just using different terminology to describe the same thing. Probably because my working background is industrial and relates to liquid systems used for manufacture of products in factories, where a tank that is physically higher than the rest of the system is described as filling the system by gravity. And as you point out the OP does indeed have an open vent too. I guess I was trying to differentiate between how the system was filled with water and the way heated water can be circulated around a circuit by natural [gravity] circulation.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links