Some applications require the chiller to be running 24 hours per day, 7 days per week. Other applications require only periodic use of the chiller. The maintenance schedule should consider the amount of time the chiller is in operation. Instead of measuring in miles like you would with a car, you’ll want to measure in terms of hours of use.
Environmental conditions also play a large role in the amount of maintenance a chiller will need. Chillers should only be used indoors at a maximum relative humidity of 80%. High humidity can result in condensation that could damage electrical components in the chiller or on the equipment it’s cooling. Chillers should also only be operated at ambient temperatures between 55°F (13°C) and 95°F (35°C). Extreme temperatures can negatively impact thermal performance, cause strain on electrical components, and/or result in freezing and bursting of the evaporator. Chillers should also only be used in areas that are relatively clean and dust free. The dustier and dirtier the air, the more maintenance your chiller is likely to need. Using an air filter is recommended if ambient air is dusty. However, it’s important to note that an air filter will add slightly to pressure drop, and therefore will cause a slight decrease in thermal performance.
The other factor that significantly impacts maintenance is the type of coolant you are using. If you are using water as your chiller coolant, it is critical that you use filtered, clean water. Water with high mineral content can lead to corrosion and fouling of your coolant passages, resulting in system clogs or leaks. Aavid recommends using a corrosion inhibitor as well as an algae inhibitor to prevent growth in the reservoir. (See Figure 2.) For example, a solution containing 30% inhibited ethylene glycol (EGW) can inhibit corrosion as well as algae growth. (See our article “Selecting a Heat Transfer Fluid for Liquid Cooling” for more information.)