DATA RECEIVED FROM OPENTHERM GENERATORS

Owned by Marco Serpelloni
Last updated: Aug 11, 2023
2 min read

By connecting a REG-OTG or a REG-OT4 to the OpenTherm generator(s), it is possible to display the data sent by the generator in the green frame:

  •  Generator Status:

    • F = Fault

    • H = Heating

    • D = Domestic production

    • F = Flame

    • C = Cooling

    • CH = Heating Second Channel

    • S = Service

    • Cg = Communication failure with the generator

  • Temperature Outlet in °C

  • Temperature Inlet in °C

  • Temperature DHW in °C

  • Power output in %: the powers are expressed in percentage, so if there are generators with different power, for example 24kW and 35kW, the same power % corresponds to different real power. Moreover, some generators give the real power output, so they consider 0% with the flame/compressor off, while with the flame/compressor on the power value read by the system is ≥ 15-17%, that is the minimum power at which they can modulate; other generators, instead, indicate the % in relation to the useful modulation range, so with 0% they indicate that the generator is operating at the minimum of its modulation (probably 15-20% of the nominal power rating) but still on. This may have an impact on the settings (although usually not a big one): for the former the minimum power = 30% probably indicates an actual 30%, while in the latter case the minimum power = 30% probably indicates roughly an actual 40% value, assuming its minimum is 15%, this would be [(100%-15%)*0,3+15%)];

  • OT Error

    • Ts = Service Request

    • Rr = Remote Reset Enabled

    • Lp = Low water pressure

    • Gf = Flame failure

    • Ap = Air pressure failure

    • Oh = Over heating

    • Cg = Communication with generator failure

  • OEM Error (see manufacturer's manual)

Warning

Each manufacturer can decide which data to implement, so for example, if OT Errors (OpenTherm) are not encoded, no box will ever be ticked. If the inlet probe is not assembled, its value will not be present in the corresponding box.

The Reset button at each of 8 generators works IF AND ONLY IF the generator manufacturer has implemented it.

On the other hand, in the purple frame are the REG System demand to the generator (depending on the settings made in the zones, circuits, sources and DHW), which can be:

  • H = Heating

  • A = Domestic Water

  • C = Cooling

  • Temp = Required temperature in Heating or Cooling in °C

  • Pow. = Required power in Heating or Cooling in %

The Required power in Domestic is always 100% and it is never displayed in the Pot. column of the purple frame.

The Temperature in DHW production mode requested from generators is displayed in the top right of the OpenTherm page in the section “Generators Demand Status” - Enable/Set DHW.