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 dea7253a9..fb76456dc 100644
--- a/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py
+++ b/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py
@@ -1557,8 +1557,8 @@ def test_water_only_heat_network_dhw_fuel_independent_of_plant_type() -> None:
     heat_pump = hw_fuel_for(952)
 
     # Assert — the plant behind the network never reaches the dwelling.
-    assert chp == pytest.approx(boilers, abs=1e-6)
-    assert heat_pump == pytest.approx(boilers, abs=1e-6)
+    assert abs(chp - boilers) <= 1e-6
+    assert abs(heat_pump - boilers) <= 1e-6
 
 
 def test_water_only_heat_network_cylinder_accrues_table_3_primary_loss() -> None:
@@ -1676,7 +1676,10 @@ def test_water_only_heat_network_primary_loss_matches_heat_network_main() -> Non
 
     # Assert — Table 3's heat-network row keys on the DHW source, not the
     # space main, so both bill the same insulated p=1.0 / h=3 loss.
-    assert water_only == pytest.approx(from_network_main, abs=1e-6)
+    assert all(
+        abs(water - from_main) <= 1e-6
+        for water, from_main in zip(water_only, from_network_main)
+    )
 
 
 def test_gas_boiler_main_efficiency_unchanged_by_dlf_override() -> None: