Depending on the site, contributors may include:

• Mechanical Engineering Consultant: Develops the test methodology, defines data logging requirements, interprets results and prepares the final report with electrification recommendations.
• Incumbent BMS Vendor Technician: Implements or approves required BMS changes, configures trend logs and ensures that all relevant system parameters are captured.
• BMS Consultant: May undertake BMS configuration and monitoring where this is not performed by the incumbent vendor.
• Incumbent Mechanical Services Contractor: May be required on site during testing to manually operate boilers, assess plant condition and monitor equipment behaviour, particularly where remote control is limited or non condensing boilers are installed.
• Facility Manager: Confirms acceptable testing windows, manages tenant communications and ensures atypical occupancy patterns do not influence test results.
• Project Lead: Coordinates activities across all parties and oversees testing execution. This role may be fulfilled by the mechanical engineer, facility manager or a nominated project representative.

The Value of Controls Knowledge

In many buildings, detailed operational knowledge sits with individuals who have supported the BMS or control strategy over an extended period. This includes understanding of warm up behaviour, plant staging logic, zone imbalances and historical operating issues.

Involving this controls expertise in the testing process can significantly improve interpretation of results. Their insight helps distinguish between limitations inherent to the physical system and those related to control settings or operational practices.

Limitations of Night Purging

Where ideal winter conditions are missed, night purging is sometimes considered as an alternative. This approach involves running air handling units on high outdoor air volumes overnight to lower internal temperatures prior to testing.

Experience has shown that night purging does not replicate genuine winter loads. Testing conducted under these conditions can overstate system capability, potentially leading to optimistic conclusions that are not borne out during actual cold weather operation.

Special Considerations of Non-Condensing Boilers

Buildings equipped with non-condensing boilers require particular care during low temperature HHW testing. These units are not designed for prolonged operation with low return water temperatures.

When return temperatures fall to approximately 55°C or below, flue gas condensation can occur within the boiler heat exchanger. Over time, this acidic condensate can lead to corrosion, reduced equipment life and increased maintenance requirements.

Low temperature testing can still be undertaken on systems with non condensing boilers, however procedures must be carefully managed to balance the value of operational insight against potential plant risk.

Using Test Outcomes to Inform Electrification Planning

When planned and executed effectively, low temperature HHW testing provides building specific insight that modelling alone cannot deliver. It allows facility managers and asset owners to make informed decisions about:

• The feasibility of low temperature heat pump operation
• The scope of required system upgrades
• The most cost effective pathway toward building electrification.

By grounding electrification planning in real world performance data, testing helps reduce uncertainty and supports more confident investment decisions.

For broader guidance on heat pump retrofits within an electrification strategy, refer to the A.G. Coombs Advisory Note: Navigating Heat Pump Retrofits — A Guide for Facility Managers.