Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Right now, based on the order in your pictures, it looks like the model will use the ERV as the primary heating source. So, the radiant system may not even turn on if the model thinks it can handle the heating load with the ERV alone. If you want the radiant system to be the primary source, it must be placed first - or you can open the osm file in a text editor and change their priorities.
After that, you might want to make sure that you are getting some flow through your radiant floors by tracking some of the node flows and temperatures.
Lastly, the throttling range you have seems narrow, so your radiant system doesn't vary its flow much (It's on at full capacity below 17.5C and it's completely off above 18.5C). This means the radiant floor will not be on unless the control temperature starts dropping right down to 18. By the time this happens, there may be a large time delay before the radiant slab can raise the indoor temperature if that's what its control is based on. Consider widening the throttling range so that the radiant slab can begin combatting the heat loss from the space before the indoor temp drops below your setpoint.
Let me know if you're still having problems after trying the strategies above.
