Heat Pump Operating Instructions
The heat pump manufacturer should provide operating instructions with the installation literature. If no copy is available, contact the manufacturer’s local field representative for one.
If no operating instructions are available for the unit, follow those contained in this section. These instructions are suitable for most electric heat pumps used in residential installations.
The first step, of course, is to turn on the power supply at the dis- connect switch. This is a very simple but important step that is often overlooked. In remote heat pump installations, both the indoor and outdoor sections may have a disconnect switch or a breaker or fuse in the house box. Both switches must be in the on position to start the system.
Move the thermostat setting as high as it will go, and switch the fan selection switch to the on setting. This should start the blower. The remainder of the operating instructions will depend on whether heating or cooling is desired.
Heating
For the heating cycle, move the fan selector switch to the auto position and slowly raise the heating temperature setting on the thermostat. Stop moving the lever as soon as the first-stage (upper) mercury bulb makes contact. The blower, compressor, and con- denser fan should start at this point.
Under normal operating conditions, the unit may automatically trip on its high-pressure cutout and stop the compressor and outdoor fan if the outdoor ambient temperature exceeds approximately 80°F. If the outdoor ambient temperature is too low for automatic
cutout, block the return air until the unit trips. In a cold climate, it may take 5 minutes or more to trip.
Check the thermostat heat anticipator setting to make sure it matches the current draw of the heating relays (see Chapter 4 of Volume 2, “Thermostats and Humidistats”), and make certain the contactors and heaters are operating correctly.
The defrost timer can be checked in the winter when the outdoor coil is cold enough to activate it. Observe at least one defrost cycle to make sure the unit defrosts properly.
Turn the thermostat off. If the unit is set at the on position, only the blower should operate. Turn the thermostat on again and pro- ceed as follows:
1. Adjust discharge air grilles for suitable airflow.
2. Check the system for proper balance and correct if necessary.
3. Check for air leaks in the ductwork and correct if necessary.
Cooling
For the cooling cycle, move the fan selector switch to the auto position and lower the heating temperature setting on the thermostat to below room temperature. This should start the blower, compressor, and condenser fan. If these components are operating satisfactorily, turn the thermostat off. The unit should stop with the exception of the blower if the thermostat is set at the on position.
If a combination heating and cooling thermostat is used, switch it to the heat position and check for correct heating operation. Make certain the thermostat heat anticipator is set to match the current draw of the heating relays (see Chapter 4 of Volume 2, “Thermostats and Humidistats”).
After waiting approximately 5 minutes, turn the air conditioner on and proceed as follows:
1. Adjust discharge air grilles.
2. Check the system for proper balancing.
3. Check for air leaks in the ductwork.