Sensing a mains voltage signal

[richylloyd]

I have towel rails in my bathrooms which are connected to the central heating (independent system) but they also have an immersion heater for summer use.  This part is controlled by Comfort.

I\'m trying to improve my controls as I can\'t detect if the central heating is on and whether to enable the immersion heater or not.

I was looking to sense the mains signal voltage from the specific central heating circuit (it is multi zone) but I can\'t seem to find a simple means of achieving this. 
A simple 220V relay connected to a RIO input seems like the solution but I can\'t find such a device.

I would prefer to purchase a simple unit rather than creating my own.
Surely someone else has had such a need and has a simple solution to offer?

[Swiss-Toni]

Comfort relay RLY01H

[richylloyd]

That only provides the output which I already have.
I\'m looking to sense the state of the central heating circuit via the mains signal from the respective thermostat/control valve.

[Swiss-Toni]

What is the amperage, you may get away with using TWS02 or use a current sensor CSM03

[richylloyd]

I\'ll check on this but as it is only a signalling voltage, I suspect it is almost nothing.

[slychiu]

To detect 230V AC you need a Relay with 230VAC coil voltageThe relay contacts can be connected to ComfortThese are quite common, eg https://sg.element14.com/c/switches-rela...age=220vac

Altenately, use CSM03-CT Current sensor with CSM03-PCB cplugged in at the Comfort inputsThe live wire should go through the current transformer holesee http://comfortforums.com/view_topic.php?id=3662&forum_id=118&jump_to=16106

[Ingo]

Here is a DB mounted relay. http://www.hager.co.uk/product-catalogue.../47246.htm

[richylloyd]

thanks, those relays are some of the ideas I will look at - they just seemed like overkill (and a bit large) for the job I was asking them to do.
I was hoping there was a very low power, compact version for interfacing with a RPI or similar.

I\'m hoping to use the CSM03 once I check the current load.

I have also found the following kit which drives a LED. Possibly I could replace the led with a RIO input as it is around 3V.
https://quasarelectronics.co.uk/Item/vel...icator-kit

[richylloyd]

So, the current draw on the mains signal line is only 8mA (3mA idle). I\'m going to struggle to get the CSM03 to read this without multiple loops through the sensor which I don\'t think is possible.

I\'ve tested the LED indicator circuit and this was not successful either.
Looks like I will try and find a suitably small 220V relay to activate the RIO input.

Anyone have awareness of such a product?

[slychiu]

CSM03-CT and PCB  connected to Comfort input will not be able to detect small currents
But if you use IRIO01 with ISM03 or an IRIO-TWS these have current sensor inputs that directly connect to a CSM03-CT and allows you to set thresholds donw to a few milliamps
see IRIO at http://www.comfortforums.com/forum129/4328.html