diff --git a/tests/domain/epc/test_main_heating_system_overlay.py b/tests/domain/epc/test_main_heating_system_overlay.py
index b42effd9b..795a9defe 100644
--- a/tests/domain/epc/test_main_heating_system_overlay.py
+++ b/tests/domain/epc/test_main_heating_system_overlay.py
@@ -95,17 +95,34 @@ def test_electric_room_heaters_overlay_the_room_heater_charge_control() -> None:
 def test_overlay_logs_when_it_cannot_complete_a_companion_set(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
-    # An archetype the overlay cannot yet fully companion — here an air-source
-    # heat pump, whose Table 4e Group 2 conservative control is not yet mapped —
+    # An archetype the overlay cannot yet fully companion — here community
+    # heating, whose Table 4e Group 3 conservative control is not yet mapped —
     # is still overlaid (log-and-continue), but the incomplete companion set is
     # logged as an error so the known gap is visible (CloudWatch) rather than
     # silently inheriting the replaced system's stale value.
     # Act
     with caplog.at_level(logging.ERROR):
-        main_heating_overlay_for("Air source heat pump", 0)
+        main_heating_overlay_for("Community heating, boilers", 0)
 
     # Assert — the gap is reported and names the archetype.
-    assert "Air source heat pump" in caplog.text
+    assert "Community heating, boilers" in caplog.text
+
+
+def test_air_source_heat_pump_drags_the_conservative_group_2_control() -> None:
+    # The landlord names the system, not its control, so the overlay assumes
+    # the conservative Table 4e Group 2 default: 2201 ("no time or thermostatic
+    # control", +0.3 C — the largest Group 2 adjustment, so an unobserved
+    # control is never over-credited; the heat-pump mirror of storage 2401 /
+    # boiler 2101). Deliberately NOT the ASHP Measure's 2210 zone control —
+    # a measure designs a modern end-state (ADR-0024); an override describes an
+    # existing pump (ADR-0053).
+    # Act
+    simulation = main_heating_overlay_for("Air source heat pump", 0)
+
+    # Assert — SAP Table 4e Group 2 conservative heat-pump control.
+    assert simulation is not None
+    assert simulation.heating is not None
+    assert simulation.heating.main_heating_control == 2201
 
 
 def test_complete_room_heater_overlay_does_not_log_a_companion_gap(