Relay doesn't turn on/off boiler after 6y - how to test

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Deda_Komarek
Posts: 14
Joined: 28 Jun 2018, 11:03

Relay doesn't turn on/off boiler after 6y - how to test

Post by Deda_Komarek »

Hello,
after summer I have some problems with thermostat and boiler. I use Netatmo thermostat for six years so I am quite experienced in use and troubleshooting, but I can't figure out what to do now.
Relay doesn't turn boiler on/off.
Thermostat (room unit) is working fine, connection with relay is stable, I can set temperatures in my phone app, I can hear click by room unit and relay also, relay diod shines white (is turned on) but boiler doesn't respond. I checked wiring, everything is ok.
I've tried to disconnect and reconnect relay, restart it, change polarity but nothing works.
I can only once change boiler from on/off by changing polarity (in app). But only once.
Any advice how to find out if it's relay malfunction or boiler?
Can I measure some voltage/current on relays ends during switching on/off ? I don't have any other thermostat to test boiler.
GEORGzer
Posts: 2500
Joined: 14 Jan 2014, 18:14

Re: Relay doesn't turn on/off boiler after 6y - how to test

Post by GEORGzer »

You can check the boiler by taking a piece of wire and putting it between the terminals the Relais is connected to. If you boiler turns on and turns off when you remove said wire, then your boiler works fine.

Regarding the Relais, you would have to check for consistency between the black and grey wires with a multimeter.
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Deda_Komarek
Posts: 14
Joined: 28 Jun 2018, 11:03

Re: Relay doesn't turn on/off boiler after 6y - how to test

Post by Deda_Komarek »

boiler works well. I could turn it on and off with connecting/disconnecting the thermostat terminals. I tried to connect relay directly to boiler and it works. I didnt mention I had relay connected to boiler through cca 3m long 4x1,5 mm2 copper wire cable, because I had wifi connectivity problems and I had to have relay closer to wifi router. I did some measuring on cable and it looks good. I think it is some "voltage/power/output drop" in relay which is now unable to turn boiler on/off through 3m cable. So I had to extend LAN cable to the basement and install wifi access point near the boiler. And now it works. I hope the drop will not to continue.
GEORGzer
Posts: 2500
Joined: 14 Jan 2014, 18:14

Re: Relay doesn't turn on/off boiler after 6y - how to test

Post by GEORGzer »

Interesting, the control-terminals of the boiler usually cary a very small voltage, 8v - 12v something like that.
The Relais only closes the circuit between the black and grey wires, they never carry any voltage.

You could have tried to connect the two ends of your cable where the black/grey wires were and check if the boiler turns on. To determinate if the Relais or the boiler/cable is at fault.


But if it works now, that’s all that matters ☺️
Home: Weather Station (V3 + Rain & Wind Gauge, 3 additional Indoor Modules, Shield), Valves Starter Pack + 7 Valves, Video Doorbell, Air Conditioner Controller
Office: Thermostat (V2), Healthy Home Coach, Smoke Alarm

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abasa
Posts: 1
Joined: 20 Jan 2023, 12:08

Re: Relay doesn't turn on/off boiler after 6y - how to test

Post by abasa »

Hello I have quite similiar issue. I have a Netatmo thermostat for some years, it has been working fine till some months ago. It is installed with the wireless type. Now I have 2 issues. One is the thermostat display, which I can fix changing it. Meanwhile I see everything in the app. The second is the strange behavior of the thermostat when the supply energy drops at home. The problem is when the relay lost the supply for some seconds, after that, it does not switch the boiler on, it means that doesn't not close the contacts. The relay recovers the connection with the Wi-Fi, and the app in my phone shows the temperature and I can increase or reduce the target temperature. If I increase the target temperature the display shows the heater ON icon, the click sounds inside it, but the relay does not close the contacts. I must go to the app and reconnect the relay again to the wifi, which is not easy because I must repeat several times to get it works. It seems like the relay is connected to the Wi-Fi and connected to the thermostat by radio, but it is not doing the switching according to the thermostat.
Boiler is ok becuase the old mechanical thermostat swith it on.
Any idea what is going on?
I doubt to repair the display if I have a problem with the relay.
The relay works perfectly while is powered.
Thanks
GEORGzer
Posts: 2500
Joined: 14 Jan 2014, 18:14

Re: Relay doesn't turn on/off boiler after 6y - how to test

Post by GEORGzer »

That is a very strange behavior indeed.
If the Relais reacts to changes in the app, then the WIFI connection can‘t be corrupted.

Honestly, if you‘re out of warranty and the Thermostat is also defective, I would consider getting a replacement. There are almost always Warehouse-Deals at Amazon for Netatmo products available.
Hardware breaks, it happens 🤷‍♂️
Home: Weather Station (V3 + Rain & Wind Gauge, 3 additional Indoor Modules, Shield), Valves Starter Pack + 7 Valves, Video Doorbell, Air Conditioner Controller
Office: Thermostat (V2), Healthy Home Coach, Smoke Alarm

Not a Netatmo employee
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