What maintenance is needed on a Geothermal Heat Pump?

Ground Source (Geothermal) Heat Pumps are installed indoors and protected from the elements, but that doesn’t mean they don’t require regular maintenance.

Just like any other heating system, routine checks will prevent small problems from turning into headaches and will also help extend system life.

Catching minor problems early is all about preventing a full breakdown of the equipment. Your heat pump isn’t prone to problems, but the last thing you want is for your heating system to shut off in the middle of winter.

The same as any furnace or air conditioner, regular maintenance will catch problems early before they cause wear on different components. Regular maintenance doesn’t have to be intensive. If you’re not technical or familiar with the equipment, set up an annual maintenance contract.

An annual check-up by a qualified technician should catch any issues before they escalate. Below we explain how to clean a heat pump and how to test the performance.

Change Your Air Filter!

This is the most important maintenance item for any forced air heating system and must be completed by the homeowner at minimum every 3 months.

Switching out your air filter is critical because all the air from your home is passing through this filter, carrying dust, debris, and mites with it. Allowing that to build up can seriously impact the performance of your system.

Ideally do a monthly inspection of your air filter, and install a replacement every 3 months, or sooner for optimal performance. This will depend on how dusty the air in your home is, i.e. if you have pets.

Basic Cleaning of Heat Pump

Ground source heat pumps are mechanical devices. They vibrate internally as they run, the compressor heats up and cools down constantly. Dust collects because of all the air being channelled from the home through the cabinet (if it doesn’t get caught by the filter). Qualified technicians performing a regular maintenance on the equipment will clean the system by:

  • Vacuuming any dust or debris collected on the inside of the cabinet blower section.
  • Use special purpose coil cleaner on air coil to clean dirt and debris
  • Lubricate the main electrical contactors.
  • Clean out the condensate drain pan – similar to an air conditioner.

Checking Heat Pump Performance

Assessing the operating performance of a heat pump is something you’ll likely have to get a technician to do. It’s worth the money for an annual check-up because if your heat pump isn’t running at peak performance, you’ll see that reflected on your electricity bills.

A qualified individual will be needed to determine if you’re getting the right amount of energy from the ground loops.

The energy your system extracts from the ground loop, is the life-long thermal energy invested in when you bought the system. The price of this energy will never increase. The energy will always be there for you, on-demand, 24/7, 365, with zero emissions. It’s in your best interest to ensure your heat pump is harvesting that energy efficiently.

Checking Air Temperature

Checking the difference in temperature of the air being returned to the unit, and comparing to the temperature of the supply air, will tell you how well the GSHP is performing.

Typically, in heating mode the supply air should be about 20-30°F warmer than the return air. If the home thermostat is set to 70°F, then the air being fed into the home’s supply ductwork should be about 90-100°F. Conversely, in cooling the air temperature drop should be about 15-25°F.

Checking Loop Fluid Temperature

If the air temperatures is giving an unusual reading, a good second indicator is to check the loop temperatures. For this check, a technician will insert a temperature gauge into the source side inspection ports on the heat pump. This will sense the temperature of the fluid arriving into the heat pump from the ground loops, and then the fluid leaving the heat pump going back out to the ground loops.

The actual temperatures will vary significantly based on location, time of year and type of loop installed (among other factors). The temperature difference between the supply and returning ground loop fluid is fairly typical and should be about 4-8°F drop in heating and 9-12°F rise in cooling.

Checking Flow Rates

If the temperature difference isn’t within specification, the technician could also check how fast the fluid is flowing in the loops. This can be done through the same ports on the heat pump they used to check the fluid temperature. This is an important indicator as proper flow rates are key to a well performing system. Without flow, there is no heat exchange.

Bringing It All Together

The final part of any maintenance/inspection is to measure the power being drawn by the heat pump. Checking the voltage and amp draw of the system will allow the technician to accurately calculate the energy input to the heat pump.

With the energy input calculated, using the values determined from analyzing the loop and air side performance, we can calculate the Coefficient of Performance (COP).

COP is a measure of energy output divided by energy input. Simply put, all the energy being collected from the ground loop, plus the energy to power the system (input), divided by the input power equals the COP.

Today’s Ground Source Heat Pumps will have an operating COP ranging from 3.5 to 5.0. That’s 350-500%! Herein lies the value of a well performing Ground Source Heat Pump system.

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