diff --git a/api/src/opentrons/drivers/utils.py b/api/src/opentrons/drivers/utils.py
index eb31427e420..30f9fabc5fd 100644
--- a/api/src/opentrons/drivers/utils.py
+++ b/api/src/opentrons/drivers/utils.py
@@ -166,7 +166,7 @@ def parse_key_values(value: str) -> Dict[str, str]:
 
 def parse_optional_number(value: str, rounding_val: int) -> Optional[float]:
     """Convert number to float. 'none' will be converted to None"""
-    return None if value == "none" else parse_number(value, rounding_val)
+    return None if value.lower() == "none" else parse_number(value, rounding_val)
 
 
 def parse_number(value: str, rounding_val: int) -> float:
diff --git a/api/src/opentrons/protocol_engine/commands/heater_shaker/deactivate_heater.py b/api/src/opentrons/protocol_engine/commands/heater_shaker/deactivate_heater.py
index 59948059754..ece233c3d9d 100644
--- a/api/src/opentrons/protocol_engine/commands/heater_shaker/deactivate_heater.py
+++ b/api/src/opentrons/protocol_engine/commands/heater_shaker/deactivate_heater.py
@@ -51,7 +51,7 @@ async def execute(self, params: DeactivateHeaterParams) -> DeactivateHeaterResul
         )
 
         if hs_hardware_module is not None:
-            await hs_hardware_module.start_set_temperature(celsius=0)
+            await hs_hardware_module.deactivate_heater()
 
         return DeactivateHeaterResult()
 
diff --git a/api/tests/opentrons/protocol_engine/commands/heater_shaker/test_deactivate_heater.py b/api/tests/opentrons/protocol_engine/commands/heater_shaker/test_deactivate_heater.py
index a9a6008b57c..0dbd7a6862d 100644
--- a/api/tests/opentrons/protocol_engine/commands/heater_shaker/test_deactivate_heater.py
+++ b/api/tests/opentrons/protocol_engine/commands/heater_shaker/test_deactivate_heater.py
@@ -43,5 +43,5 @@ async def test_deactivate_heater(
     ).then_return(hs_hardware)
 
     result = await subject.execute(data)
-    decoy.verify(await hs_hardware.start_set_temperature(celsius=0), times=1)
+    decoy.verify(await hs_hardware.deactivate_heater(), times=1)
     assert result == heater_shaker.DeactivateHeaterResult()