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Flow Control – Separate Heat Pumps

Checks for flow rate and control on separate heat pump systems.

Pump Type and Flow Rate

  1. Check pump type: Is it constant speed or variable? This determines the TRNSYS template selection and pump modelling approach.
  2. Check pump flow rate: Obtain from the AS/NZS 5125.1 test report.

Flow Control

  1. Determine whether flow is controlled or uncontrolled. Reference: AS/NZS 4234 Clauses 3.7.3, 3.7.4, H3.2.

  2. If controlled flow, verify evidence is provided for:

    • Flow meter installed at each installation
    • Flow meter used during commissioning
    • Flow rate set by controller
    • Orifice restrictor instructions
  3. If variable flow: Check that the HP is tested over a range of flow rates.

Piping

  1. Pipe length: Modelled pipe lengths to and from the HP must be at least 5 m.
  2. Pipe diameter and insulation: Obtain evidence for specifications, otherwise use 16 mm inner diameter as default.