diff --git a/domain/sap10_calculator/rdsap/cert_to_inputs.py b/domain/sap10_calculator/rdsap/cert_to_inputs.py
index f39b006d..5298b0c5 100644
--- a/domain/sap10_calculator/rdsap/cert_to_inputs.py
+++ b/domain/sap10_calculator/rdsap/cert_to_inputs.py
@@ -792,6 +792,12 @@ _SECONDARY_HEATING_FRACTION_BY_CATEGORY: Final[dict[int, float]] = {
     5: 0.10,
     6: 0.10,
     7: 0.15,
+    9: 0.10,   # Warm-air systems (NOT heat pump): a gas/oil warm-air unit
+               # is an "All gas, liquid and solid fuel systems" row (0.10),
+               # and electric warm air is "Other electric systems" (also
+               # 0.10) — so 0.10 regardless of fuel (SAP 10.2 Table 11
+               # p.188). Cert 0380 (warm air mains gas, code 506, +
+               # electric room-heater secondary) raised here before.
     10: 0.20,
 }
 _SECONDARY_HEATING_FRACTION_DEFAULT: Final[float] = 0.10
diff --git a/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py b/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py
index 4b2d13c3..08a25d75 100644
--- a/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py
+++ b/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py
@@ -3352,6 +3352,13 @@ def test_secondary_heating_fraction_for_category_full_table_11_coverage() -> Non
     assert _secondary_heating_fraction_for_category(5) == 0.10
     assert _secondary_heating_fraction_for_category(6) == 0.10
     assert _secondary_heating_fraction_for_category(7) == 0.15
+    # Category 9 = warm-air systems (NOT heat pump). A gas/oil warm-air
+    # unit is an "All gas, liquid and solid fuel systems" row (0.10);
+    # electric warm air is "Other electric systems" (also 0.10) — so 0.10
+    # regardless of fuel (SAP 10.2 Table 11 p.188). Cert 0380-2197-2590-
+    # 2996-2715 (warm air mains gas, code 506, + electric room-heater
+    # secondary) previously raised UnmappedSapCode here, blocking it.
+    assert _secondary_heating_fraction_for_category(9) == 0.10
     assert _secondary_heating_fraction_for_category(10) == 0.20
     # Absent
     assert _secondary_heating_fraction_for_category(None) == 0.10