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Control Modes and Setpoints

This guide provides comprehensive information about the ALPHA HWR's control modes and setpoint configuration.

Overview

The ALPHA HWR pump supports multiple control modes, each designed for specific application requirements. Control modes can be configured via:

  • Physical operating panel (limited modes)
  • Mobile application (all modes)
  • alpha-hwr library (all modes via CLI or Python API)

Reading Current Setpoint

CLI

# Read current control mode and setpoint
alpha-hwr control status

Python API

from alpha_hwr import AlphaHWRClient

async with AlphaHWRClient("AA:BB:CC:DD:EE:FF") as client:
    await client.authenticate(fast_mode=True)

    # Read current setpoint
    setpoint_info = await client.control.get_mode()

    if setpoint_info:
        print(f"Control Mode: {setpoint_info.control_mode.name}")
        print(f"Setpoint: {setpoint_info.setpoint}")
        print(f"Range: {setpoint_info.min_setpoint} - {setpoint_info.max_setpoint}")

Control Modes Available via Operating Panel

Temperature Control - AUTOADAPT

Description: Ensures comfort via integrated temperature estimator, suitable for all hot-water recirculation applications with a dedicated return line.

Features:

  • Automatically adjusts flow according to temperature setpoint
  • Ensures hot water availability throughout the house
  • Meets minimum flow requirement for tankless water heaters
  • Flow rate: 1-4 GPM (automatically adjusted)
  • Temperature range: 95-102°F (35-39°C)

Use Case: General hot-water recirculation with optimal energy efficiency

Temperature Control

Description: Ensures comfort via flow limits based on predefined pipe diameters.

Features:

  • Maintains temperature between 95-102°F (35-39°C)
  • Flow limits designed to reduce flow-accelerated corrosion
  • Operates on maximum curve until reaching flow limits

Flow Limits by Pipe Diameter:

  • 1/2": 1.5 GPM
  • 3/4": 2.3 GPM
  • 1": 3.8 GPM

Use Case: Systems where flow-accelerated corrosion is a concern

Continuous Operation - 24/7

Description: Ensures comfort through continuous operation in constant curve III with flow limits.

Features:

  • Continuous operation
  • Flow limits based on predefined pipe diameters
  • Reduces flow-accelerated corrosion and noise

Flow Limits (adjustable via Bluetooth interface):

  • 1/2": 1.5 GPM
  • 3/4": 2.3 GPM
  • 1": 3.8 GPM

Use Case: Applications requiring 24/7 hot water availability

Control Modes Available via Bluetooth Interface

The ALPHA HWR supports 5 primary control modes specifically optimized for hot water recirculation.

1. Temperature Control (Mode 27)

Description: Controls pump operation to maintain water temperature within a specified range. This is the recommended mode for most DHW applications.

Features: - Min/Max Temperature: Configurable range (default 35-39°C). - AUTOADAPT: Automatic flow adjustment (1-4 gpm) to maintain comfort and efficiency. - Flow Limits: Can be limited based on pipe diameter to prevent corrosion.

Example: 

# Set range 35-39°C with AUTOADAPT enabled
alpha-hwr control set-temperature --min 35 --max 39 --autoadapt

# Set range 40-45°C with AUTOADAPT disabled and 1.5 GPM limit
alpha-hwr control set-temperature --min 40 --max 45 --no-autoadapt --flow-limit 1.5

2. Cycle Time Control (Mode 25)

Description: Pump operates at maximum curve with configurable on/off cycles.

Parameters: - On time: 1-60 minutes - Off time: 1-60 minutes

Example: 

# Set 5 minutes ON, 15 minutes OFF
alpha-hwr control set-cycle-time --on 5 --off 15

3. Constant Curve / Constant Speed (Mode 2)

Description: Pump runs at a fixed rotational speed (RPM).

Features: - Setpoint: 1000-4500 RPM. - Flow Limits: Optional GPM limit to prevent noise and corrosion.

Example: 

# Set to 2500 RPM with 2.3 GPM limit (3/4" pipe)
alpha-hwr control set-speed 2500 --flow-limit 2.3

4. Constant Pressure (Mode 0)

Description: Maintains a fixed head pressure regardless of flow.

Setpoint: 0.5-6.0 meters.

Example: 

alpha-hwr control set-pressure 1.5

5. Constant Flow (Mode 8)

Description: Maintains a fixed flow rate regardless of head pressure.

Setpoint: 0.1-3.0 m³/h.

Example: 

alpha-hwr control set-flow 0.5

Flow Limitation and Pipe Diameters

The ALPHA HWR allows setting a maximum flow limit to prevent flow-accelerated corrosion (FAC) and noise in the system. Limits are typically chosen based on pipe diameter:

Pipe Diameter Recommended Limit
1/2" 1.5 GPM
3/4" 2.3 GPM
1" 3.8 GPM

CLI: 

alpha-hwr control set-flow-limit 1.5

Proportional Pressure (Mode 1)

Proportional pressure mode is also fully supported and adjusts pressure along a curve based on flow.

CLI: 

alpha-hwr control set-proportional 1.2

Deprecated/Unsupported Modes

The following modes are defined in the GENI protocol but are not recommended for ALPHA HWR as they are designed for heating systems (radiators/underfloor heating) rather than DHW recirculation: - AUTOADAPT Radiator (Mode 13) - AUTOADAPT Underfloor (Mode 14) - AUTOADAPT Combined (Mode 15) - AUTOADAPT Generic (Mode 5)

Use Temperature Control (Mode 27) with the --autoadapt flag instead.

Temperature Range Control

Mode ID: 27
Special Handling: Uses dual setpoints (high/low temperature)

Description: Controls pump operation to maintain water temperature within a specified range.

Setpoints:

  • Low Temperature: Minimum temperature limit
  • High Temperature: Maximum temperature limit
  • AutoAdapt Flag: Enable/disable automatic delta temperature adjustment

Default Range: 32.95-41.11°C (91-106°F)
Nominal Range (per manual): 35-39°C (95-102°F)

Reading Temperature Range:

alpha-hwr control status
# Output will show min/max temperatures for this mode

Data Source: Object 91, Sub-ID 430 (TemperatureRangeControlUserSettings, Type 1012)

Setpoint Data Structures

Standard Modes (Object 86, Sub-ID 6)

Type 303: OperationRequest

Structure:

[ControlSource(1)][OperationMode(1)][ControlMode(1)][Setpoint(4)]
  • ControlSource: Source of control command
  • OperationMode: Current operation mode
  • ControlMode: Active control mode (0-27)
  • Setpoint: Target value (float32, big-endian)

Limit Configuration (Object 86, Sub-IDs 11-39)

Type 301: FactoryConfig

Standard Format (float32):

[DefaultSetpoint(4)][MinSetpoint(4)][MaxSetpoint(4)][...]

AutoAdapt Generic Format (uint16 with padding):

[DefaultSetpoint(2)][Padding(2)][MinSetpoint(2)][Padding(2)][MaxSetpoint(2)][Padding(2)]

Sub-ID Mapping:

  • Sub 11: AutoAdapt Generic (uint16)
  • Sub 13: Constant Speed (float32)
  • Sub 15: Constant Pressure (float32)
  • Sub 17: Proportional Pressure (float32)
  • Sub 19: AutoAdapt Radiator (float32)
  • Sub 21: AutoAdapt Underfloor (float32)
  • Sub 23: AutoAdapt Combined (float32)
  • Sub 39: Constant Flow (float32)

Temperature Range Control (Object 91, Sub-ID 430)

Type 1012: TemperatureRangeControlUserSettings

Structure:

[DeltaTempEnabled(1)][MinTemp(4)][MaxTemp(4)][MinOffTime(1)][MaxOffTime(1)][MinOnTime(1)][MaxOnTime(1)]
  • DeltaTempEnabled: AutoAdapt flag (bool)
  • MinTemp: Low temperature limit (float32, °C)
  • MaxTemp: High temperature limit (float32, °C)
  • Time limits: On/off timing parameters

Unit Conversions

The library automatically handles unit conversions for display:

Pressure Modes

  • Stored as: Pascals (Pa)
  • Displayed as: Meters of water column (m)
  • Conversion: 1 m H₂O ≈ 9806.65 Pa

Flow Modes

  • Stored as: m³/h
  • Displayed as: m³/h (no conversion)

Speed Modes

  • Stored as: RPM
  • Displayed as: RPM (no conversion)

Temperature Modes

  • Stored as: °C
  • Displayed as: °C (no conversion)

Best Practices

  1. Choose the Right Mode:
  2. For hot water recirculation: Temperature Control - AUTOADAPT
  3. For predictable scheduling: Cycle Time Control
  4. For legacy system replacement: Constant Curve
  5. For multi-zone systems: Constant Pressure

  6. For external control: Constant Flow

  7. Setpoint Selection:

  8. Start with factory defaults
  9. Adjust based on system performance

  10. Use --limits flag to see allowed ranges

  11. Energy Efficiency:

  12. Use AUTOADAPT modes when possible
  13. Enable scheduling for time-based control

  14. Set appropriate temperature ranges (don't overheat)

  15. System Protection:

  16. Respect flow limits for pipe diameter
  17. Monitor for corrosion in high-flow applications
  18. Use minimum flow settings for tankless heaters

See Also

  • CLI Guide - Complete CLI command reference
  • Data Models - SetpointInfo model documentation
  • Hardware Reference - Physical specifications
  • User Manual: See resources/reference/92992176_0224_ALPHA_HWR_CS_DB.md in the repository