diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index 500a72cd..c1360e86 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -817,6 +817,14 @@ class EpcPropertyDataMapper:
             main_heating=EpcPropertyDataMapper._map_energy_elements(
                 schema.main_heating
             ),
+            # First control system if multiple — mirrors from_rdsap_schema_21_0_1.
+            main_heating_controls=(
+                EpcPropertyDataMapper._map_energy_element(
+                    schema.main_heating_controls[0]
+                )
+                if schema.main_heating_controls
+                else None
+            ),
             window=(
                 EpcPropertyDataMapper._map_energy_element(schema.windows)
                 if schema.windows is not None
diff --git a/datatypes/epc/schema/sap_schema_17_1.py b/datatypes/epc/schema/sap_schema_17_1.py
index 8f6fc2da..5cad983c 100644
--- a/datatypes/epc/schema/sap_schema_17_1.py
+++ b/datatypes/epc/schema/sap_schema_17_1.py
@@ -220,6 +220,7 @@ class SapSchema17_1:
     # reads. Dropped by the WIP mapper → all "Unknown" on the FE (ADR-0037).
     # Full-SAP lodges windows under the plural key (a single element, not a list).
     main_heating: List[EnergyElement] = field(default_factory=list)
+    main_heating_controls: List[EnergyElement] = field(default_factory=list)
     windows: Optional[EnergyElement] = None
     lighting: Optional[EnergyElement] = None
     hot_water: Optional[EnergyElement] = None