Merge pull request #40 from eman/fix/temperature-conversion-formula

Fix: Correct temperature conversion formula for 8 sensor fields

Author: eman

CHANGELOG.rst

@@ -2,6 +2,36 @@
 Changelog
 =========
 
+Version 6.0.5 (2025-11-21)
+==========================
+
+Fixed
+-----
+
+- **CRITICAL Temperature Conversion Bug**: Corrected temperature conversion formula for 8 sensor fields that were displaying values ~100°F higher than expected. The v6.0.4 change incorrectly used division by 5 (pentacelsius) instead of division by 10 (decicelsius) for these fields:
+  
+  - ``tank_upper_temperature`` - Water tank upper sensor
+  - ``tank_lower_temperature`` - Water tank lower sensor
+  - ``discharge_temperature`` - Compressor discharge temperature (refrigerant)
+  - ``suction_temperature`` - Compressor suction temperature (refrigerant)
+  - ``evaporator_temperature`` - Evaporator coil temperature (refrigerant)
+  - ``ambient_temperature`` - Ambient air temperature at heat pump
+  - ``target_super_heat`` - Target superheat setpoint
+  - ``current_super_heat`` - Measured superheat value
+  
+  **Impact**: These fields now correctly display temperatures in expected ranges:
+  
+  - Tank temperatures: ~120°F (close to DHW temperature, not ~220°F)
+  - Discharge temperature: 120-180°F (not 220-280°F)
+  - Suction, evaporator, ambient: Now showing physically realistic values
+  
+  **Technical details**: Changed from ``PentaCelsiusToF`` (÷5) back to ``DeciCelsiusToF`` (÷10). The correct formula is ``(raw_value / 10.0) * 9/5 + 32``.
+
+Changed
+-------
+
+- **Documentation**: Updated ``data_conversions.rst`` and ``device_status.rst`` to reflect correct ``DeciCelsiusToF`` conversion for refrigerant circuit and tank temperature sensors
+
 Version 6.0.4 (2025-11-21)
 ==========================
 

docs/protocol/data_conversions.rst

@@ -24,11 +24,11 @@ The device uses several encoding schemes to minimize transmission overhead:
    - Purpose: Converts raw values, which are in half-degrees Celsius, to Fahrenheit.
    - Example: Raw 122 -> (122 / 2) * 9/5 + 32 = 141.8°F
 
-2. **Scaled Celsius to Fahrenheit** (PentaCelsiusToF)
-   - Applied to refrigerant and evaporator temperatures.
-   - Formula: ``displayed_value = (raw_value / 5.0) * 9/5 + 32``
-   - Purpose: Converts raw values, which are scaled by a factor of 5, to Fahrenheit.
-   - Example: Raw 250 -> (250 / 5) * 9/5 + 32 = 122°F
+2. **Decicelsius to Fahrenheit** (DeciCelsiusToF)
+   - Applied to refrigerant circuit and tank temperature sensors.
+   - Formula: ``displayed_value = (raw_value / 10.0) * 9/5 + 32``
+   - Purpose: Converts raw values, which are in tenths of degrees Celsius, to Fahrenheit.
+   - Example: Raw 489 -> (489 / 10) * 9/5 + 32 = 120.0°F
 
 3. **Tenths Encoding** (div_10)
    - Applied to decimal precision values
@@ -97,11 +97,11 @@ Tank Temperature Sensors
      - Display Unit
      - Description
    * - ``tankUpperTemperature``
-     - PentaCelsiusToF
+     - DeciCelsiusToF
      - °F
      - **Upper tank sensor temperature**. Indicates stratification - hot water at top for quick delivery. Typically hottest point in tank.
    * - ``tankLowerTemperature``
-     - PentaCelsiusToF
+     - DeciCelsiusToF
      - °F
      - **Lower tank sensor temperature**. Indicates bulk tank temperature and heating progress. Typically cooler than upper sensor.
 
@@ -121,27 +121,27 @@ These temperatures monitor the heat pump refrigerant circuit health and performa
      - Display Unit
      - Description
    * - ``dischargeTemperature``
-     - PentaCelsiusToF
+     - DeciCelsiusToF
      - °F
      - **Compressor discharge temperature**. Temperature of refrigerant exiting the compressor. Typically 120-180°F. High values indicate high system pressure; low values indicate efficiency issues.
    * - ``suctionTemperature``
-     - PentaCelsiusToF
+     - DeciCelsiusToF
      - °F
      - **Compressor suction temperature**. Temperature of refrigerant entering the compressor. Typically 40-60°F. Affects superheat calculation.
    * - ``evaporatorTemperature``
-     - PentaCelsiusToF
+     - DeciCelsiusToF
      - °F
      - **Evaporator coil temperature**. Where heat is extracted from ambient air. Typically 20-50°F. Lower outdoor air temperature reduces evaporator efficiency.
    * - ``ambientTemperature``
-     - PentaCelsiusToF
+     - DeciCelsiusToF
      - °F
      - **Ambient air temperature** measured at heat pump inlet. Directly affects system performance. At freezing (32°F), heat pump efficiency drops significantly.
    * - ``targetSuperHeat``
-     - PentaCelsiusToF
+     - DeciCelsiusToF
      - °F
      - **Target superheat setpoint**. Desired temperature difference between suction and evaporator ensuring complete refrigerant vaporization. Typically 10-20°F.
    * - ``currentSuperHeat``
-     - PentaCelsiusToF
+     - DeciCelsiusToF
      - °F
      - **Measured superheat value**. Actual temperature difference. Deviation from target indicates EEV (Electronic Expansion Valve) control issues.
 

docs/protocol/device_status.rst

@@ -122,37 +122,37 @@ This document lists the fields found in the ``status`` object of device status m
      - integer
      - °F
      - Temperature of the upper part of the tank.
-     - PentaCelsiusToF
+     - DeciCelsiusToF
    * - ``tankLowerTemperature``
      - integer
      - °F
      - Temperature of the lower part of the tank.
-     - PentaCelsiusToF
+     - DeciCelsiusToF
    * - ``dischargeTemperature``
      - integer
      - °F
      - Compressor discharge temperature - temperature of refrigerant leaving the compressor.
-     - PentaCelsiusToF
+     - DeciCelsiusToF
    * - ``suctionTemperature``
      - integer
      - °F
      - Compressor suction temperature - temperature of refrigerant entering the compressor.
-     - PentaCelsiusToF
+     - DeciCelsiusToF
    * - ``evaporatorTemperature``
      - integer
      - °F
      - Evaporator temperature - temperature where heat is absorbed from ambient air.
-     - PentaCelsiusToF
+     - DeciCelsiusToF
    * - ``ambientTemperature``
      - integer
      - °F
      - Ambient air temperature measured at the heat pump air intake.
-     - PentaCelsiusToF
+     - DeciCelsiusToF
    * - ``targetSuperHeat``
      - integer
      - °F
      - Target superheat value - the desired temperature difference ensuring complete refrigerant vaporization.
-     - PentaCelsiusToF
+     - DeciCelsiusToF
    * - ``compUse``
      - bool
      - None
@@ -307,7 +307,7 @@ This document lists the fields found in the ``status`` object of device status m
      - integer
      - °F
      - Current superheat value - actual temperature difference between suction and evaporator temperatures.
-     - PentaCelsiusToF
+     - DeciCelsiusToF
    * - ``heatUpperUse``
      - bool
      - None

src/nwp500/models.py

@@ -41,10 +41,10 @@ def _half_celsius_to_fahrenheit(v: Any) -> float:
     return float(v)
 
 
-def _penta_celsius_to_fahrenheit(v: Any) -> float:
-    """Convert value scaled by 5 to Fahrenheit."""
+def _deci_celsius_to_fahrenheit(v: Any) -> float:
+    """Convert decicelsius (tenths of Celsius) to Fahrenheit."""
     if isinstance(v, (int, float)):
-        celsius = float(v) / 5.0
+        celsius = float(v) / 10.0
         return (celsius * 9 / 5) + 32
     return float(v)
 
@@ -53,9 +53,7 @@ def _penta_celsius_to_fahrenheit(v: Any) -> float:
 DeviceBool = Annotated[bool, BeforeValidator(_device_bool_validator)]
 Div10 = Annotated[float, BeforeValidator(_div_10_validator)]
 HalfCelsiusToF = Annotated[float, BeforeValidator(_half_celsius_to_fahrenheit)]
-PentaCelsiusToF = Annotated[
-    float, BeforeValidator(_penta_celsius_to_fahrenheit)
-]
+DeciCelsiusToF = Annotated[float, BeforeValidator(_deci_celsius_to_fahrenheit)]
 
 
 class NavienBaseModel(BaseModel):
@@ -289,15 +287,15 @@ class DeviceStatus(NavienBaseModel):
     he_lower_off_diff_temp_setting: Div10
     recirc_dhw_flow_rate: Div10
 
-    # Temperature fields with 1/5 scaling
-    tank_upper_temperature: PentaCelsiusToF
-    tank_lower_temperature: PentaCelsiusToF
-    discharge_temperature: PentaCelsiusToF
-    suction_temperature: PentaCelsiusToF
-    evaporator_temperature: PentaCelsiusToF
-    ambient_temperature: PentaCelsiusToF
-    target_super_heat: PentaCelsiusToF
-    current_super_heat: PentaCelsiusToF
+    # Temperature fields with decicelsius (÷10) to Fahrenheit conversion
+    tank_upper_temperature: DeciCelsiusToF
+    tank_lower_temperature: DeciCelsiusToF
+    discharge_temperature: DeciCelsiusToF
+    suction_temperature: DeciCelsiusToF
+    evaporator_temperature: DeciCelsiusToF
+    ambient_temperature: DeciCelsiusToF
+    target_super_heat: DeciCelsiusToF
+    current_super_heat: DeciCelsiusToF
 
     # Enum fields
     operation_mode: CurrentOperationMode = Field(

tests/test_models.py

@@ -118,11 +118,11 @@ def test_device_status_half_celsius_to_fahrenheit(default_status_data):
     assert status.dhw_temperature == pytest.approx(141.8)
 
 
-def test_device_status_penta_celsius_to_fahrenheit(default_status_data):
-    """Test PentaCelsiusToF conversion."""
-    default_status_data["tankUpperTemperature"] = 250
+def test_device_status_deci_celsius_to_fahrenheit(default_status_data):
+    """Test DeciCelsiusToF conversion."""
+    default_status_data["tankUpperTemperature"] = 489
     status = DeviceStatus.model_validate(default_status_data)
-    assert status.tank_upper_temperature == pytest.approx(122.0)
+    assert status.tank_upper_temperature == pytest.approx(120.0, abs=0.1)
 
 
 def test_device_status_div10(default_status_data):