Device Feature Fields

This document lists the fields found in the feature object (also known as

Warning

This document describes the underlying protocol details. Most users should use the Python client library (MQTT Client) instead of implementing the protocol directly.

Note

Capability Flag Pattern: All capability flags (fields ending in Use) follow the same pattern as OnOffFlag:

• 2 = Supported/Available (feature is present on this device)

• 1 = Not Supported/Unavailable (feature is not present on this device)

This is the standard Navien protocol pattern for boolean-like values, not traditional 0/1 booleans. The Python library automatically converts these to Python bool (True/False).

The DeviceFeature data contains device capabilities, configuration, and firmware information received via MQTT when calling request_device_info(). This data is much more detailed than the basic device information available through the REST API and corresponds to the actual device specifications and capabilities as documented in the official Navien NWP500 Installation and User manuals.

Field Name	Type	Units	Description	Conversion Formula
countryCode	int	None	Country/region code where device is certified for operation. Device-specific code defined by Navien; earlier documentation referenced code 1, but current USA devices report code 3	None
modelTypeCode	int	None	Model type identifier: NWP500 series electric heat pump water heater model variant	None
controlTypeCode	int	None	Control system type: Advanced digital control with LCD display and WiFi connectivity	None
volumeCode	int	Gallons	Tank nominal capacity: 50, 65, or 80 gallons (NWP500-50/65/80 models)	None
controllerSwVersion	int	None	Main controller firmware version - controls heat pump, heating elements, and system logic	None
panelSwVersion	int	None	Front panel display firmware version - manages LCD display and user interface	None
wifiSwVersion	int	None	WiFi module firmware version - handles WiFi app connectivity and cloud communication	None
controllerSwCode	int	None	Controller firmware variant/branch identifier for support and compatibility	None
panelSwCode	int	None	Panel firmware variant/branch identifier for display features and UI capabilities	None
wifiSwCode	int	None	WiFi firmware variant/branch identifier for communication protocol version	None
controllerSerialNumber	str	None	Unique serial number of the main controller board for warranty and service identification	None
powerUse	int	Boolean	Power control capability (2=supported, 1=not supported) - can be turned on/off via controls (always 2=supported for NWP500)	None
holidayUse	int	Boolean	Vacation mode support (2=supported, 1=not supported) - energy-saving mode for 0-99 days with minimal operations	None
programReservationUse	int	Boolean	Scheduled operation support (2=supported, 1=not supported) - programmable heating schedules and timers	None
dhwUse	int	Boolean	Domestic hot water functionality (2=supported, 1=not supported) - primary function of water heater (always 2=supported)	None
dhwTemperatureSettingUse	int	Boolean	Temperature adjustment capability (2=supported, 1=not supported) - user can modify target temperature	None
dhwTemperatureMin	int	°F	Minimum DHW temperature setting: 95°F (35°C) - safety and efficiency lower limit	HalfCelsiusToF
dhwTemperatureMax	int	°F	Maximum DHW temperature setting: 150°F (65.5°C) - scald protection upper limit	HalfCelsiusToF
smartDiagnosticUse	int	Boolean	Self-diagnostic capability (2=supported, 1=not supported) - 10-minute startup diagnostic, error code system	None
wifiRssiUse	int	Boolean	WiFi signal monitoring (2=supported, 1=not supported) - reports signal strength in dBm for connectivity diagnostics	None
temperatureType	TemperatureUnit	Enum	Default temperature unit preference (CELSIUS=1, FAHRENHEIT=2) - factory set to Fahrenheit for USA	Enum
tempFormulaType	int	None	Temperature calculation method identifier for internal sensor calibration and conversions	None
energyUsageUse	int	Boolean	Energy monitoring support (2=supported, 1=not supported) - tracks kWh consumption for heat pump and electric elements	None
freezeProtectionUse	int	Boolean	Freeze protection capability (2=supported, 1=not supported) - automatic heating when tank drops below threshold	None
freezeProtectionTempMin	int	°F	Minimum freeze protection threshold: 43°F (6°C) - factory default activation temperature	HalfCelsiusToF
freezeProtectionTempMax	int	°F	Maximum freeze protection threshold: typically 65°F - user-adjustable upper limit	HalfCelsiusToF
mixingValueUse	int	Boolean	Thermostatic mixing valve support (2=supported, 1=not supported) - for temperature limiting at point of use	None
drSettingUse	int	Boolean	Demand Response support (2=supported, 1=not supported) - CTA-2045 compliance for utility load management	None
antiLegionellaSettingUse	int	Boolean	Anti-Legionella function (2=supported, 1=not supported) - periodic heating to 140°F (60°C) to prevent bacteria	None
hpwhUse	int	Boolean	Heat Pump Water Heater mode (2=supported, 1=not supported) - primary efficient heating method using refrigeration cycle	None
dhwRefillUse	int	Boolean	Tank refill detection (2=supported, 1=not supported) - monitors for “dry fire” conditions during refill	None
ecoUse	int	Boolean	ECO safety switch (2=supported, 1=not supported) - Energy Cut Off high-temperature limit protection	None
electricUse	int	Boolean	Electric-only mode (2=supported, 1=not supported) - heating element only operation for maximum recovery speed	None
heatpumpUse	int	Boolean	Heat pump only mode (2=supported, 1=not supported) - most efficient operation using only refrigeration cycle	None
energySaverUse	int	Boolean	Energy Saver mode (2=supported, 1=not supported) - hybrid efficiency mode balancing speed and efficiency (default)	None
highDemandUse	int	Boolean	High Demand mode (2=supported, 1=not supported) - hybrid boost mode prioritizing fast recovery over efficiency	None

Operation Mode Support Matrix

The NWP500 supports five primary operation modes as indicated by the capability flags:

Mode ID	Mode Name	Capability Flag	Description & Performance Characteristics
1	Heat Pump Only	heatpumpUse	Most Efficient - Uses only the heat pump compressor and evaporator. Longest recovery time but highest energy efficiency. Performance varies with ambient temperature and humidity.
2	Energy Saver (Default)	energySaverUse	Balanced Efficiency - Hybrid mode combining heat pump with backup electric elements. Factory default setting balances efficiency with reasonable recovery time.
3	High Demand	highDemandUse	Fastest Recovery - Hybrid mode prioritizing speed over efficiency. Uses heat pump plus more frequent electric element operation for maximum hot water supply.
4	Electric Only	electricUse	Emergency/Service Mode - Uses only 3,755W heating elements (upper and lower, not simultaneously). Least efficient but operates in all conditions. Auto-reverts after 72 hours.
5	Vacation	holidayUse	Maximum Energy Savings - Suspends normal heating for 0-99 days. Only freeze protection and anti-seize operations continue. Heating resumes 9 hours before vacation end.

Hardware Specifications from Manual Cross-Reference

The device feature data corresponds to these official NWP500 specifications:

Electrical System

• Input: 208-240V AC, 60Hz, 1-Phase

• Current Draw: 208V (25.9A) / 240V (28.8A)

• Circuit Protection: 30A breaker required

• Heating Elements: 3,755W @ 208V or 5,000W @ 240V (upper and lower)

• Heat Pump Compressor: 11.6A

• Evaporator Fan: 0.22A

Physical Models

• NWP500-50: 50 gallon, Ø21.7” × 63” (229 lbs)

• NWP500-65: 65 gallon, Ø25” × 63” (265 lbs)

• NWP500-80: 80 gallon, Ø25” × 71.6” (282 lbs)

Safety & Compliance Features

• FCC ID: P53-EMC3290 (Class B digital device)

• IC: 23507-EMC3290 (Industry Canada RSS-210)

• NSF/ANSI 372 certified (lead-free wetted surfaces <0.25%)

• Temperature & Pressure relief valve (150 psi)

• ECO (Energy Cut Off) high-limit safety switch

Smart Features & Connectivity

• WiFi app connectivity

• Self-diagnostic system with error codes

• CTA-2045 Demand Response module support

• Anti-Legionella periodic disinfection (1-30 day intervals)

• Programmable operation schedules

Firmware Version Interpretation

The device returns three separate firmware components for full system identification:

Main Controller (``controllerSwVersion``, ``controllerSwCode``)

• Manages heat pump compressor, heating elements, temperature sensors

• Controls operation mode logic and safety interlocks

• Handles diagnostic routines and error detection

• Serial number provided for warranty tracking

Display Panel (``panelSwVersion``, ``panelSwCode``)

• User interface and LCD display management

• Button input processing and menu navigation

• Status indicator control and user feedback

WiFi Module (``wifiSwVersion``, ``wifiSwCode``)

• Cloud connectivity and app communication

• Wireless network management and security

• Remote monitoring and control capabilities

Temperature Range Validation

The reported temperature ranges align with official specifications and use the same conversion patterns as DeviceStatus fields:

• DHW Range: 95°F to 150°F (factory default: 120°F for safety) - uses HalfCelsiusToF conversion

• Freeze Protection: Activates at 43°F, prevents tank freezing - uses HalfCelsiusToF conversion

• Anti-Legionella: Heats to 140°F at programmed intervals (requires mixing valve)

• Scald Protection: Built-in limits with recommendation for thermostatic mixing valves

Conversion Pattern Consistency: Temperature fields in DeviceFeature use the same HalfCelsiusToF conversion formula as corresponding fields in DeviceStatus, ensuring consistent temperature handling across all device data structures.

HalfCelsiusToF Formula: fahrenheit = (raw_value / 2.0) * 9/5 + 32

Usage Example

import asyncio
from nwp500 import NavienAuthClient, NavienMqttClient, NavienAPIClient

async def analyze_device_capabilities():
    async with NavienAuthClient("email@example.com", "password") as auth_client:
        # Get device list
        api_client = NavienAPIClient(auth_client)
        devices = await api_client.list_devices()
        device = devices[0]

        # Connect MQTT and request device features
        mqtt_client = NavienMqttClient(auth_client)
        await mqtt_client.connect()

        # Set up callback to analyze device capabilities
        def analyze_features(feature):
            print(f"=== Device Capability Analysis ===")
            print(f"Model: NWP500-{feature.volumeCode} ({feature.volumeCode} gallon)")
            print(f"Controller FW: v{feature.controllerSwVersion} (Code: {feature.controllerSwCode})")
            print(f"Panel FW: v{feature.panelSwVersion} (Code: {feature.panelSwCode})")
            print(f"WiFi FW: v{feature.wifiSwVersion} (Code: {feature.wifiSwCode})")
            print(f"Serial: {feature.controllerSerialNumber}")

            print(f"\n=== Temperature Capabilities ===")
            print(f"DHW Range: {feature.dhwTemperatureMin}°F - {feature.dhwTemperatureMax}°F")
            print(f"Freeze Protection: {feature.freezeProtectionTempMin}°F - {feature.freezeProtectionTempMax}°F")
            print(f"Default Unit: {feature.temperatureType.name}")

            print(f"\n=== Supported Operation Modes ===")
            modes = []
            if feature.heatpumpUse: modes.append("Heat Pump Only")
            if feature.energySaverUse: modes.append("Energy Saver (Default)")
            if feature.highDemandUse: modes.append("High Demand")
            if feature.electricUse: modes.append("Electric Only")
            if feature.holidayUse: modes.append("Vacation Mode")
            print(f"Available: {', '.join(modes)}")

            print(f"\n=== Smart Features ===")
            features = []
            if feature.smartDiagnosticUse: features.append("Self-Diagnostics")
            if feature.wifiRssiUse: features.append("WiFi Monitoring")
            if feature.energyUsageUse: features.append("Energy Tracking")
            if feature.antiLegionellaSettingUse: features.append("Anti-Legionella")
            if feature.drSettingUse: features.append("Demand Response")
            if feature.mixingValueUse: features.append("Mixing Valve Support")
            print(f"Available: {', '.join(features)}")

        await mqtt_client.subscribe_device_feature(device, analyze_features)
        await mqtt_client.request_device_info(device)

        # Wait for response
        await asyncio.sleep(5)
        await mqtt_client.disconnect()

asyncio.run(analyze_device_capabilities())

See Also

• Device Status Fields - Real-time device status field reference

• MQTT Client - MQTT client usage guide for device communication

• API Client - REST API client for device management

• Error Codes - Complete error code reference for diagnostics