Connection of modulating thermostat to boiler

MarcV
Posts: 880
Joined: 22 Aug 2016, 09:01
Location: Schoten, Belgium

Connection of modulating thermostat to boiler

Post by MarcV »

I need to replace the boiler in my heating system. I'm currently using the original, non-modulating Netatmo thermostat to control the boiler. The boiler is controlled by the contact in the thermostat, not by the contact in the relay.

I do not know what type of new boiler will be installed yet but it is likely going to be a modulating type, which means I'll have to install a new Netatmo modulating thermostat also.

I would like to know if, with the modulating thermostat, it is also possible to control the boiler by the thermostat or can it only be controlled by the relay?
...but I might be wrong...
sergeantd83
Posts: 84
Joined: 12 Nov 2020, 13:21

Re: Connection of modulating thermostat to boiler

Post by sergeantd83 »

Hi Marc,

You have to connect the Relay to the OpenTherm terminals of the boiler. There is no wired connection for the thermostat with the boiler.
Mark@BC
Posts: 279
Joined: 15 Nov 2019, 21:32

Re: Connection of modulating thermostat to boiler

Post by Mark@BC »

👍
1x Presence outdoor camera siren V3.18.0
2x Thermostat V76 + 10x Valves V100 + relais 236
1x weather station v202, outdoor module V53 and additional indoor module V53
GEORGzer
Posts: 2663
Joined: 14 Jan 2014, 18:14

Re: Connection of modulating thermostat to boiler

Post by GEORGzer »

Interesting, I did not know that.
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MarcV
Posts: 880
Joined: 22 Aug 2016, 09:01
Location: Schoten, Belgium

Re: Connection of modulating thermostat to boiler

Post by MarcV »

Thanks. I already suspected this but wasn't sure...
...but I might be wrong...
GEORGzer
Posts: 2663
Joined: 14 Jan 2014, 18:14

Re: Connection of modulating thermostat to boiler

Post by GEORGzer »

@sergeantd83

Does the Modulating Thermostat itself have no connectors at all or just for dry-contact usage like the analog Thermostat?
Home: Weather Station (V3 + Rain & Wind Gauge, 3 additional Indoor Modules, Shield), Valves Starter Pack + 7 Valves, Video Doorbell
Office: Thermostat (V2), Healthy Home Coach, Smoke Alarm, 2 2in1 Sensors

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sergeantd83
Posts: 84
Joined: 12 Nov 2020, 13:21

Re: Connection of modulating thermostat to boiler

Post by sergeantd83 »

No connectors at all for the thermostat, just wireless communication with the Relay ( It can be mounted on a wall or it can be placed on a table just like the smart thermostat ). Only the relay can be connected to the boiler.
GEORGzer
Posts: 2663
Joined: 14 Jan 2014, 18:14

Re: Connection of modulating thermostat to boiler

Post by GEORGzer »

Thanks for the lesson ☺️
Home: Weather Station (V3 + Rain & Wind Gauge, 3 additional Indoor Modules, Shield), Valves Starter Pack + 7 Valves, Video Doorbell
Office: Thermostat (V2), Healthy Home Coach, Smoke Alarm, 2 2in1 Sensors

Not a Netatmo employee
canacchione
Posts: 21
Joined: 21 Sep 2022, 09:08

Re: Connection of modulating thermostat to boiler

Post by canacchione »

sergeantd83 wrote: 29 Sep 2022, 21:56 No connectors at all for the thermostat, just wireless communication with the Relay ( It can be mounted on a wall or it can be placed on a table just like the smart thermostat ). Only the relay can be connected to the boiler.
I did not know this thing, so in my case, when I go to replace the intelligent netatmo to the wires that come from the boiler already connected on the 3-4 position of the terminals (opentherm) I do not have to connect directly the netatmo modulating thermostat but the relay. But if I remember correctly the relay has 4 wires two serve for power, which means that I will also have to bring two wires to power it. Did I understand correctly??
sergeantd83
Posts: 84
Joined: 12 Nov 2020, 13:21

Re: Connection of modulating thermostat to boiler

Post by sergeantd83 »

You are right, the relay connection process is the same with the smart thermostat when you connect the relay to the boiler directly. The Black and Grey cables of the modulating thermostat relay have to be connected to the 3-4 OpenTherm terminals of your boiler and Blue-Brown wires to the mains.
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