Replaced Drayron RTS1 thermostat with wired Tado, now heating doesn't work
We have a simple, but unusual, for the UK, heating system. The cylinder is a thermal store, whereby the main water content is heated by an, always on, Bosch gas boiler, but is supplemented by heat from a solar panel and a solid fuel boiler. This cylinder water is used as the water for the heating system, and, by use of coils in the cylinder, heats water for domestic use.
There is a Drayton controller, which is wired so the boiler is constantly on. The heating side just switches the central heating pump on and off as called for by the Drayton RTS1 thermostat. All the radiators, except one, have thermostatic valves. The RTS1 is located in an unheated hallway. As we live in a bungalow there are no zones.
Overall a very efficient and economical system.
I decided it could be improved, so yesterday replaced the RTS1 with a Tado wired thermostat. Installation went smoothly, guided by the Tado app.
Only thing is that now there is no heating at all. The boiler still works, but I expected that as it is remote from heating system. Changing Tado thermostat temperature up or down has no effect.
Is there something I have misunderstood?
Comments
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Sorry - should have had this in above comment:
The programmer now has heating as constantly on. I am wondering if the Tado doesn't have enough power to control the pump directly and needs it to operate via a relay?
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You wondering if the stat does not have the wellie to switch on the pump?
We had that problem at the charity centre. A CH pump, particularly a high powered one, has a switching current of 10 amps. Old school bimetal thermostats can handle that punch. Smart stats don't, they can handle a sustained 3Amp current but anything over 5amps starting current doesn't complete its kickoff.
It's the reason why we use relays between our thermostat and the pump. Just buy one which has a delayed switch off of upto 1 min. Dead easy to wire in.0 -
That's what I think the problem might be - any suggestions as to suitable relays and how to wire in?
Thanks
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This link
https://community.tado.com/en-gb/discussion/23910/what-is-the-wiring-to-connect-a-wired-thermostat-to-a-relay
1. Install a 30mm patress box on the wall near your pump
2. Run the switched live from the stat into it.
3. Get the neutral and earth from the wiring centre near the boiler into that patress box.
4.Throw on a blank lid on the front.
Should work.
This may look like a strange question...do you have an under floor heating wiring centre with an unused relay point?0 -
I have a neighbour who had a similar problem when he installed a TADO, and thinks he might know what problem is, and is popping round tomorrow to see. He says it is because of the way the TADO is constructed and the front of the thermostat latches to the backplate.
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Well please come back and let us know what you found and what worked.
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At his suggestion I changed the backplate attachment to the wall from the screws to the sticky foam tape and it now switches the pump ok.
He thinks the backplate plastic is too soft, and moulds itself to any imperfections of the wall, and although it appears the front plate has locked ok it doesn't.
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Hilarious. Will remember that. We have 30 charity buildings, each throws problems once every 3-4 months. Will look out for these.
@Emcee. A bug request please?
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@Waspman @policywonk
The backplate being too soft is interesting. I've never heard of that before. I'll forward it to the appropriate team.0
