Winter conditions can introduce additional challenges for chiller systems.
While lower ambient temperatures can improve efficiency, they also increase the risk of freezing, control instability and component stress if systems are not properly maintained.
Read our ‘chiller maintenance winter checklist’ to prevent damage to your chillers and unnecessary increases in costs this winter.
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Prevent freezing
To prevent freezing in your chiller, it is essential to make sure the amount of glycol in your system is at the correct level. The glycol levels should be checked and maintained on a regular basis during winter. The correct amount you need in your system should be specified in the documentation issued with the unit.
It is also important to check for any damage and corrosion on the trace heating tape and any connections. This can help ensure there’s no risk of failure and the pipes freezing. When doing any electrical checks, this must be carried out by a qualified engineer using the correct equipment.
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Clean coils
Coils can suffer from a gradual build-up of dirt, mould and airborne pollutants throughout the year.
If not addressed before winter, this build-up can restrict airflow and reduce heat transfer efficiency. This results in a loss of performance and efficiency, and therefore increased energy consumption and running costs.
This can all be avoided by regular cleaning and maintenance of the coils. To help the coils remain clean, remove any waste, rubbish and general debris from the surrounding area of the chiller.
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Other parts to clean and examine
- Condenser intake filter: air intake filter panels should be removed, examined and cleaned. If dirt builds up, it will have the same impact as a dirty condenser coil.
- Protective condenser fin/coil coating: after the fins and coil have been cleaned up, examine the fin coating. The condenser fins and coil may have been treated with an anti-corrosion protective spray, so check to ensure this isn’t damaged.
When cleaning the coils don’t use a hard or wire brush, a soft hand brush or purpose made narrow coil brush should be used to prevent damage to the coating.
- Panels and steelwork: wash down all panels and steel work and repair/treat when necessary. Ensure there isn’t any water accumulation around and under any supporting structure. Any dirt or mould left untreated or cleaned off will become permanent and may become corrosive.
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Check for leaks
Leaks lead to a lot of wasted energy and money, something every business is trying to avoid. Water leaks are generally obvious, and when noticed should be repaired immediately.
Refrigeration leaks are harder to detect and generally require a leak test by a qualified engineer. Get in touch if you need an engineer to carry out a leak test.
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Examine insulation
It’s important to ensure insulation is in good condition to prevent unwanted heat gain or loss, maintain stable temperatures, and avoid condensation or freezing risks.
It should be checked to make sure there are no condensation leaks, repair and replace the insulation wherever necessary.
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Set for maximum efficiency
Where system design allows, reviewing and optimising setpoints in line with seasonal conditions can improve efficiency.
Any adjustments should be made carefully to ensure they remain within process requirements and manufacturer recommendations.
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Check crankcase and evaporator heaters
Crankcase and evaporator heaters are fitted to most chillers. Crankcase heaters are critical in colder conditions as they prevent refrigerant from condensing into the compressor oil.
Without proper heating, this can lead to oil dilution and potential damage during start-up.
Crankcase and evaporator heaters should be checked, tested and replaced where appropriate.
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Check low ambient operation controls
In colder conditions, air-cooled chillers can experience low head pressure, which may affect system stability and performance.
Ensure that any low ambient control measures, such as fan speed control or head pressure valves, are operating correctly.