Open Circuit Voltage
Posted: Wed Jan 06, 2016 12:25 pm
I am new to the forum and I am approaching for the first time OpenTherm interface.
I have an ATAG Q15S boiler which at the moment doesn't have a dedicated controller (on/off room thermostat are controlling only floor valves).
I'd like to add an OTGW to control the boiler, but before buying I want to be sure it is compliant (because it is not listed inside the compatibility list).
The ATAG Wize controller (which is instead present in the list) claims to be compatible with my boiler.
I did this preliminary checks with multimeter and few resistors I have at home:
Open circuit voltage: 10.69V
Resistor load 10.90k: 8.87v
Resistor load 3k25: 8.77v
Resistor load 1k717: 8.59v
So it seems the boiler is providing 5mA only with low load.
I would have expected an higher voltage with open circuit (and with 3k25 something like 16V).
I am right?
Which is the experience of other users?
Thanks in advance,
m.
I have an ATAG Q15S boiler which at the moment doesn't have a dedicated controller (on/off room thermostat are controlling only floor valves).
I'd like to add an OTGW to control the boiler, but before buying I want to be sure it is compliant (because it is not listed inside the compatibility list).
The ATAG Wize controller (which is instead present in the list) claims to be compatible with my boiler.
I did this preliminary checks with multimeter and few resistors I have at home:
Open circuit voltage: 10.69V
Resistor load 10.90k: 8.87v
Resistor load 3k25: 8.77v
Resistor load 1k717: 8.59v
So it seems the boiler is providing 5mA only with low load.
I would have expected an higher voltage with open circuit (and with 3k25 something like 16V).
I am right?
Which is the experience of other users?
Thanks in advance,
m.