ILS error codes

If one of the following errors occurs on an ILS base circuit, a comfort issue is applicable. It means that one of the assumptions made by the ILS algorithm (see https://hysopt.atlassian.net/wiki/spaces/HRM/pages/3089367491 ) could not be realized for more than 5% of the time, implying some kind of comfort issue.

The ILS simulation result is INVALID and, because of that reason, not reliable.
You will need to fix the comfort issue to create a valid and reliable simulation result!

• error code 2
  cause: the imposed volume flow for heating for an individual dwelling was larger than the design flow
  this can occur if e.g. the supply temperature is too low, if the room setpoint temperature is higher than the room design temperature (20), or if the outside temperature is lower than -10.
  solution: adapt the supply temperature, the room setpoint temperature, or modify your design conditions
  
  

• error code 4
  cause: the imposed volume flow for heating, secondary from the heat exchanger, for an individual dwelling was larger than the design flow. This can occur if e.g. the controlled radiator supply temperature is too low, if the room setpoint temperature is higher than the room design temperature (20), or if the outside temperature is lower than -10.
  solution: adapt the supply temperature, the controlled radiator supply temperature, the room setpoint temperature, or modify your design conditions
  
  

• error code 8
  cause: the central heating setpoint configuration does not comply with the central heating diversity standard as defined on the settings page. The peak flows exceeded the flows as defined by the diversity standard.
  solution:

  • Either change the diversity standard in the settings page
    
    

    Open

    

  • either change the setpoint configuration (simulation parameter)
    
    

    Open

    

     

• error code 16
  cause: the imposed volume flow for Domestic Hot Water for an individual dwelling was larger than the design flow, this can occur if e.g. the supply temperature is too low
  solution: adapt the supply temperature or the domestic hot water temperature
  
  

• error code 32
  cause: the room temperature could not be realised. This can occur if e.g. the supply temperature or controlled radiator supply temperature is too low, the room setpoint temperature is higher than the room design temperature (20) or the outside temperature is lower than -10
  solution: adapt the supply temperature, the controlled radiator supply temperature, the room setpoint temperature, or modify your design conditions
  
  

• error code 64
  cause: the primary supply temperature is lower than the secondary controlled radiator supply temperature
  solution: adapt the supply temperature or the controlled radiator supply temperature

• error code 128
  cause: the supply temperature is lower than the Domestic Hot Water temperature
  solution: adapt the supply temperature or the Domestic Hot Water temperature

ILS error codes on individual time steps

If an ILS base circuit does NOT raise an error during simulation, that means that during less than 5% of the time, an ILS error occurred. That’s a good situation, but it means that it still might happen in a few time steps that one of the ILS assumptions was wrong. In these particular timesteps, the simulation results for that timestep are invalid. It is possible to visualise the timesteps on which the ILS simulation resulted in an error code. This might help in “explaining” why sometimes during an ILS simulation you might see some short unexpected results, or a spike or a glitch in a graph that you cannot explain.

As an example, here you can see the resulting return temperature of an ILS simulation.
Two spikes seem odd and cannot be explained.

By selecting the “ILS error code(s)”, the graph shows the moments when an error occurs.

You can see that the spikes occurred on a timestep that an ILS error occurred, making the return temperatures on these two time steps invalid.

To analyse which error code(s) occurred, take a look at the resulting error code value, this value is the sum of all error codes that occurred.

In the example above the value is 40, meaning that two error codes (32 and 8) occurred on these timesteps.

ILS common mistakes

1. Do not control the pump, as it will conflict with the imposed flow

2. Do not use control valves, as they will conflict with the imposed flow