Control Settings | Knowledge Base

Control strategy is defined by the manufacturer or developed with the client to maximize certificate returns. Consult the client on their preference.

Legionella Control Strategy

Ask the client which approach they prefer:

Option 1: Daily 45% boost to 60°C

HP sensor must have > 45% tank volume above it
AS/NZS 5125.1 test data must show sensors T1–T3 reaching ≥ 60°C during all test conditions

Option 2: Daily boost to ~55°C + weekly 90% boost to 61°C

Bottom tank sensor must have > 90% tank volume above it
AS/NZS 5125.1 test data must show sensors T1–T5 all reaching ≥ 60°C by end of heat-up cycle in all test conditions

Reference: AS 3498:2020 Clause 7.2 — weekly (a) and daily (b) are the only applicable methods for HPWHs.

Residential systems (SRES, VEU 1D/3C) maximize certificates with:

Lower setpoint: 50–55°C
Higher deadband (typically 10–15 K)
Note: Ensure adequate hot water availability for customers, balancing setpoint reduction against system capacity

Commercial systems (VEU Activity 44) maximize certificates with:

Installation manual must reflect modelled control logic.
If setpoint < 60°C: Installation manual must state that user control changes revert to default within 24 hours.