Help with 3 channel thermostat
I’ve looked online and it seems possible to connect still. I currently have two thermostats (one downstairs and one upstairs). Do I need the extension kit or an extra tado wired thermostat to make this work?
Or do I ditch the whole thing and get the Drayton 3 channel set up.
Thanks in advance for any help.
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It can be made to work with your current Tado equipment if you tie your two heating zones together. This means that you will lose independent control of your upstairs and downstairs temperatures - heating will be based only on the one Tado thermostat, which can be placed wherever you like (doesn’t have to be where either of your existing thermostats are). I have this situation in my home, but all my radiators have Tado TRVs so everywhere is effectively re-zoned.
If you want to keep your existing upstairs and downstairs zones, I think you would need another Tado thermostat, and just use these to replace your existing upstairs and downstairs stats. You would then use your existing EPH programmer to set both zones to ‘always on’ and control the heating with Tado. You would continued to control your hot water schedule with the EPH programmer - the Tado wireless receiver would not be used.0 -
@LR13
Some things aren't clear in your request. Would you be in a position to clarify the following?
1. Is there a zone valve for CH downstairs and another which allows flow for upstairs? They may both look like honeywell two port valves. The wiring then goes to a wiring box, which also receives wires from the thermostats upstairs and downstairs
2. Is your boiler a combie? Giving the model may also help.
3. Do you have a hot water tank and is the flow to that also controlled by a two port or three port valve?
Riello burners are common to many oil fired boilers but the actual brand and model of boiler determine how it is controlled. Please identify the brand and model.0 -
It occured to me that this link: Central Heating Controls and Zoning - DIYWiki would help you understand what my last post was on about. Go to that page, look up S PLAN PLUS, there will be a picture with three motorised valves and a three channel programmer.
In practice a three zone system is just a two zone system with an extra zone valve that is switched open when there is a call for heat from that zone. If you can come back with the answers to the previous questions it will help.
Now the drawing of the 3 zone system with a 3 channel controller works on this basis
1. HW zone valve is wired into pins 1, 2, 3 and 12, with pin 7 determining whether it is opened or shut. Notice that the cylinder stat connected to pin 2, 6 and 7 then controls it.
2. CH ZONE ONE is wired into pins 1, 2, 3 5 and 12, with pin 5 determining if open or shut. The wired room stat connected to pins 2, 4 and 5 then controls it.
3. The CH ZONE TWO is wired into pins 1, 2, 3 10 and 12. Pin 10 determines if open or shut. The wired stat on pins 2, 8 and 10 then controls it.
3. To drive CH ZONE TWO on a two channel programmer, like the Tado extension kit, this is the change to be made to the wiring centres wiring.
- Move the CH ZONE 2 thermostat wire from pin 8 to pin 4.
- Leave the wire to pin 10 unmoved.
4. Then install the two wired thermostats replacing the old ones.
5. Then fit the extension kit, aka the wireless receiver as follows:
- Live from pin 1 on the wiring centre to Live on the receiver.
- Neutral from pin 2 on the wiring centre to Neutral on the receiver.
- Pin 4 from the wiring centre to CH NO.
- Pin 6 from the wiring centre to HW NO
NOW. If you did not understand any of this, best to get a sparkie involved to prevent any damage or electrocution.
Double check the logic in your own head if you do this, to make sure. Label wires as you go along. And keep photos so if you have to go back a step you can.
It could be that the wiring centre wasn't organised like this and if needed you need to organise it to match.
Do not do any wiring whilst the power is on.
Good luck.
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@14spc thank you. That makes sense as in the zones don’t matter if I get the valves for al radiators. I wasn’t planning to get TRV’s for them all tho as we have quite a lot. And I think I would need a professional to bridge the two zones? I’m not very handy lol.0
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@policywonk this is so helpful thank you. The post with the extra details has made this make sense to me. Although wouldn’t trust myself to do the work without something going majorly wrong. But it sounds like it should be fairly easy for a spark to do 😊. I’m not opposed to getting someone in to help as long as I know it’s possible to do, happy to pay someone to make sure it’s done right.
From your first post, I think here are separate zone valves for the upstairs and downstairs heating as well as the hot water as we can then the hot water on independently of the heat and the heat in both zones are controlled by seperate thermostats / can be operated independently.0 -
In that case you will need an electrician to tidy up the cabling and that includes tidying up the wiring centre. Print the text in this thread and also the picture which presents the Three Zone S PLUS wiring for him.
- There's anywhere between 2 hours and a day's work involved. This isnt difficult.
- It is not necessary to have the whole house on one CH zone. Two CH Zones make sense as downstairs can drop its temp during the night, whilst upstairs will need heat.
- Having lots of Smart TRVs made a great deal of difference to me. We put them in the most used rooms first to save money.
Contact Tado support and ask them to define how the zone controllers through the wired stats work in relation to the wireless centres. You will need them to guide you through the app. If they drag their feet, then @davidlyall and @wateroakley should be up for this to explain that to you.
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