Geothermal Heat Pump Systems Part Four – Recommendations for Operation and Maintenance

In the first three parts in our series on geothermal heat pump systems, we discussed ways to determine if this type of system is right your facility; how to get started with design by conducting a formation thermal conduc­tivity test and how to distinguish between the types of heat pumps available. Once you have decided to install a geothermal heat pump system, there are several things to consider once the system is fully operational:

Perform Routine Maintenance

As with all HVAC systems, geothermal heat pumps require routine maintenance. In particular, cleaning the system’s strainers and cleaning and replacing air filters regu­larly will help avoid an increase in pressure drop, which in turn, causes inefficiency and reduced air or water flow. This reduced air or water flow causes the compressor to work harder, ultimately causing premature system failure. While occasional compressor failure is common, multiple failures across the system or repeated failures in the same unit could indicate a larger issue. Therefore, routinely monitoring compressor failures can save you time, energy and money.

Adjust Set Backs and Set Ups

Similar to traditional systems, geothermal heat pumps allow you to make scheduled temperature adjustments—in the form of set backs or set ups—based on building oc­cupancy. However, geothermal systems take longer to warm up than other systems and may require adjustments to the set back or set up time to accommodate this start up lag.

Incorporate System Fill Alarm

Most commercial geothermal heat pump systems use a closed-con­denser water loop, which typically has an automatic fill feature to maintain the desired level of water volume in the system. And while a small amount of water is commonly lost through the process of cleaning strainers and other routine maintenance tasks, a significant or continuous flow through the automatic fill can indicate a leak in the bore field. Installing a water meter with alarm capabilities could help to alert maintenance staff of this danger and avoid excessive water usage.

Monitor Energy Use

Once the system has been in operation for one year, it is a good idea to con­sult an engineer to measure and verify your building’s energy consumption to confirm your system is achieving its indented efficiency. Comparing actual energy use to an energy model for the system could help you identify operational deficiencies that can help you maximize the system’s efficiency.

We hope that this series on geothermal heat pump systems will help you make a more informed decision when considering the HVAC system for your next project. If you have any questions about geothermal systems, please contact Michael Rader, PE at or (717) 845-7654.

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