Working With It: Operating
Checkout Procedure
After installation, flushing and testing - and prior to operation - the geothermal heat pump system should be evaluated using a checkout procedure.
Follow the heat pump manufacturer's checkout list, which usually include the steps outlined in the links below:
1. Measure the flow rate of the water through the loop system.
This can be done using one of two methods - a calibrated flow meter or the pressure drop method. If the latter is used:
- Measure the water pressure entering and leaving the heat exchanger. There should be a small pressure drop or pressure difference.
- Using manufacturer published data, find the measured pressure drop and read the corresponding flow rate. Typically, this should be about two to three gpm per nominal ton of cooling capacity.
For example, a three-ton heat pump should have about six to nine gpm flow for correct operation.
2. Check the temperature of the water entering the heat pump.
During heating operation, this should be between 25 to 80 degrees. During cooling operating, it should be between 40 and 110 degrees.
Once it has been determined that the flow rate and entering water temperature are acceptable, the heat pump is ready to be turned on and checked for correction operation.
3. Turn the system on.
With the thermostat fan position "on," the blower should start.
4. Set the room thermostat for the appropriate mode - heating or cooling - and measure the water and air temperatures.
In the cooling mode, there should be about a 10 degree difference between the entering and leaving water temperatures. The entering and leaving air temperature difference should be about 16-20 degrees.
In the heating mode, there should be a four to eight degree difference in water temperature. The air temperature difference should be about 25-35 degrees.
5. Turn the thermostat to a higher heating setting.
Check to see that the emergency heat - if installed, operates.
6. Set the thermostat to the desired comfort level.
Rule
Learn more about:
Working With It: Troubleshooting
Resources: Incentives & Financing
rule
Brochures and fact sheets
GeoThermal: Bringing Comfort to Your World
By Alliant Energy
[PDF format – 7 pages, 174kb]
