Evohome + Baxi Neta Tec Combi Boiler

7 May 2015
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United Kingdom

First post so apologies if this question has been answered previously.

Just bought a new build house that is fitted with a Baxi Neta Tec combi boiler. The central heating system has been designed to current building regulations so has 2 zones (upstairs & downstairs). The system was controlled by two danfoss Tp500 and two zone valves.

I have since bought an evohome base pack and a Hr92 for all radiators in my house (now to become a 9 zone system). I have removed then danfoss Tp500's, set the two zone valves to manually open. I have removed the link from the boiler to the tp500's and the zone valves. I now have a link from the adjacent spur to the live, neutral & earth terminals on the boiler. I have then installed a 5 core cable as shown in the attached picture.

Please could you confirm this wiring set up is correct? I have factory reset the evohome controller and bdr91 then bound them together. Signal strength is excellent but the evohome controller wont activate the relay. When i select heating off on the controller the green light stays active.

Any help would be much appreciated.
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Firstly, Evohome is not particularly diy friendly, there are Honeywell certified installers out there (such as myself).

Have your cleared the original BDR binding?

Have you set the BDR binding to boiler relay?

Assume you are not using HW pack as it has not been mentioned.
Also there is a foible where if you do not use guided config, the zones sometimes dont call the boiler relay.
Hi Simon,

Thanks for the reply

Yes i pressed the button on the front for 15 seconds. The BDR was binded as a boiler relay.

No HW pack as its a combi so i presume i dont need one?

I cant remember if used the guided config or not. I will reset all items to factory settings tonight and use the guided config?


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I don't recall having those problems Simon. I hardly ever use guided config, although Lou and Rob did tell me of one situation where it was vital. I'm bluggered if I can remember what.

Might have been using multiple zone valves :?: :confused:
No joy :(

Factory reset all components (bdr91, controller & Hr92). Ran through the guided config and still the relay wouldnt turn off the boiler via the controller when the quick action 'Heating Off' was pressed.

I used a piece of flex to manually contact A & B and this fired up the boiler and turned it when i disconnected them ... May this suggest the relay is faulty?
Is the green LED turning on and off in relation to demand from the zones?

If it is not, then wiring is not an issue and can be discounted completely.

Bear in mind that the demand from the zones does not give a BDR demand immediately, this can take 5 minutes or so.

Remove the batteries and the mains from the Base Unit for 5 mins, then let the system reboot itself by reinstating them.

If this does not work you could have a duff BDR.
The BDR91 seems to receive a signal to turn on when demand is received from the zones. But when the demand is not required the relay does not click off, the green light stays on.

I will try the reboot option later.

Think i have found the problem.

I have got the controller and relay to talk. Set the heating to come on via the controller, relay activates (light goes green) boiler comes on. I then use the quick action button to turn the heating off. This is where i believe i have a problem.

When i installed the hr92's i had to use the adopters as i had danfoss valves. The problem is that the hr92's arent closing the radiators valves completely. When i manually went round (after taking all hr92's off) and completely closed the valves the relay clicked off and the boiler went off.

I adjusted the stroke on the valves to 1 and still no joy?

How can i resolve this problem?? I am effectively using the hr92's as valve controls on the system.
Take the heads off.

Wind the valves fully open then put the heads back on. Leave it all alone for ten minutes and in that time the valves should self adjust to the throw of the bodies.

You'll hear the valves moving.

Don't underestimate the time between asking for something to happen and the system responding.

Evo works best when it is set up and scheduled properly. . . Tinkering and fine tuning should be done gradually over a matter of days.

I took the hr92's off , twisted the head anti clockwise so that radiator valve was now fully open. I then re attached hr92 which then performed it's cycle .. Requested heating on via the controller .. Hr92's adjust ok , relay clicks on , boiler fires up ..

Leave it for a while and schedule heating to go
Off , the valves adjust to 5 degrees in off mode , but this again didn't close them completely so the boiler was still firing and the relay wouldn't switch off :(
twisted the head anti clockwise so that (

I said twist the valve. Not the head.

In my experience there is something you are not getting right on the set up. this is the reason Honeywell do not offer end user support on Evo.
My suggestion is to get someone, preferably a Specialist like Simon or Myself (we don't' cover your area though) to come and sort it out.

Reading the instructions is often the first mistake people make :LOL:

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