Should refrigeration plant and cold store electrical panels be included in a thermography survey?

Yes. Refrigeration plant runs continuously, often at high load, and a failed supply can put a whole store of chilled or frozen stock at risk. Compressor starters and drives, condenser fan panels, plant room distribution boards and the boards serving cold stores can all be thermally imaged live, with nothing switched off.

What to include

Plant room distribution boards feeding the refrigeration system.
Compressor motor starters, contactors and variable speed drives, including their incoming terminals and cable connections.
Condenser and gas cooler fan panels, which are often outdoors and exposed to weather.
Refrigeration control panels and isolators serving evaporators and cold store doors.
Distribution boards in and around cold stores and blast freezers.

When to image them

Thermography needs equipment carrying a typical load, because a connection with little current through it shows little heat. Refrigeration load follows the compressors: it rises during pull-down after deliveries and in warm weather, and drops as the plant cycles off. The best time to image is when the compressors are running steadily, and the load should be recorded with every image so later surveys can be compared fairly.

Traps a thermographer has to avoid

Some components in refrigeration panels are warm by design, and a survey that reports them as faults wastes the engineer’s time.

Defrost and anti-condensation heaters, and their supplies, run warm when they are working.
Drives and soft starters give off heat from their heatsinks in normal running. What matters is the connections, compared with a matching reference.
Shiny metal and enclosures can reflect heat from elsewhere in the plant room, so readings are taken on suitable surfaces.
Moving between cold and warm areas can fog a camera lens. The route is planned so the camera is acclimatised before imaging.

What the report shows

Each finding comes with thermal and visual images, the measured temperature, exactly where it was taken, the ambient, and the difference in °C from a like-for-like reference. Findings are prioritised so maintenance can be planned around production and stock movements. Ti inspects and reports; the site’s refrigeration and electrical contractors investigate and carry out any work.

Equipment that can’t be switched off is the kind Ti surveys every week. At commissioning on a London data centre build, our thermography found 16 busbar sections over 80 °C under test load, the highest 103.5 °C at a tap-off unit, all located with nothing switched off.

Frequently asked questions

Does the plant need to be stopped?

No. The survey is carried out live. Panel covers are removed by the site’s authorised person under its own permit system.

How often should refrigeration panels be surveyed?

On the same cycle as the rest of the site, typically annually, with a re-survey of any equipment where findings were repaired.

Can the cold store evaporators themselves be imaged?

Their electrical supplies and isolators can. The survey covers electrical connections; refrigeration performance is a matter for the refrigeration engineer.