During the dog days of summer, it’s more important than ever to make sure the air conditioning system is well-maintained to avoid the system letting you down when you need it most. The same thing applies if you depend on a heat pump unit for comfort during the summer months. How does a heat pump differ from a standard air conditioner or central air system? Here’s the short version…
How a heat pump system works
Central air conditioning systems rely on two separate units to cool the air inside the home: a furnace, or air handler, which may be located in a basement or closet space within the house or apartment, and a condensing unit which is located outside. Similar to a window or room air conditioner, the heat pump is a single unit, but it can provide both cool air during the warmer months and heat during the colder ones.
The temperature is regulated by a thermostat control that may be attached to the unit itself or mounted to a nearby wall. When the thermostat is lowered or detects an increase in temperature, it closes a circuit, allowing 240 volts of alternating current to be sent to the compressor and blower fan. The compressor acts as a pump, compressing refrigerant in gas form into the heat pump’s condenser coils where the gas is condensed into a hot liquid. The coils dissipate the heat as the liquid travels through them, assisted by the spinning fan motor blades. After passing through the condenser coils, the refrigerant travels to the evaporator coils. There the refrigerant expands back into a gas which makes the coils cold. The blower fan draws air past the cold evaporator coils and forces the air through the unit’s vent to cool the interior of the house, apartment, or hotel room.
Unique to heat pumps is a reversing valve that can reverse the direction of the refrigerant through the cycle when heat is required. This will effectively make the condensing coils behave like an evaporator, and the evaporator coils behave like a condenser. The heat that is dissipated when the unit is in its cooling mode will, instead, be forced through the front vent to warm the air in the room.
Three important heat pump maintenance tips
Performing regular maintenance is the best way to ensure the heat pump will function efficiently in both warmer and colder temperatures. Before you attempt any maintenance, be sure the unit is turned off and the power supply has been disconnected. Here are the three most important maintenance procedures you should consider doing:
- Clean the air filter or filters – The heat pump’s air filters should be cleaned every thirty days to ensure unimpeded air flow. You can vacuum off any heavy residue and even run water through the filters to assist in cleaning. When doing this, be sure to allow the filters to thoroughly dry being reinstalling them. Of course, if a filter is torn or damaged, you should replace it with a new one.
- Inspect and clean the condenser coils – The unit’s condenser coils should be inspected and cleaned regularly, preferably every six months if the heat pump is in frequent use. If the heat pump unit is mounted in a wall, such as a Packaged Terminal Air Conditioner (PTAC) often found in hotel rooms and apartments, you will need to uninstall the unit from the wall sleeve and move it outside to safely clean the coils. You may also need to uninstall the fan motor housing to reach both sides of the coils. To clean the coils, you can use warm water and a mild detergent, but you should never use a high-pressure spray. For heavier soiling, you can use a dedicated non-acidic coil cleaning solution. Wearing clothes and eye protection, spray the solution into the coil fins from the bottom up. Wait three-to-five minutes, then flush the coils with fresh water.
- Use gel-tabs to keep drain pan clog-free – Over time, a heat pump unit’s base pan can become clogged with debris or residue build-up which can prevent the pan from draining condensate properly. You should place one or more specifically-formulated gel-tabs in the area most likely to collect condensate to help keep the pan clean and clog-free. The gel-tabs will also help eliminate odors and should be replaced every three months for maximum effectiveness.
Top causes of a heat pump not cooling
So, you’ve performed regular maintenance on the heat pump, but the unit is not cooling as expected. What do you do? Here are the top three potential causes you should investigate:
- A faulty control board or relay may prevent voltage reaching the compressor and fan motor, preventing one or both from running. You can visually inspect the control board for signs of burning or a shorted-out component. Depending on the model, you may also be able to test the heat pump’s relays with a multimeter. First touch the meter probes to the incoming contracts to confirm that the relay is receiving voltage. After setting the thermostat to call for cooling, test the coil terminals to determine that voltage is present. If true, the coil should be energized and the relay contacts should be closed, sending 240 volts to the compressor and fan motor. If the 24 volt coil is open, or 240 volts is not present at the outlet terminals, the contacts are likely damaged, and the relay or control board will need to be replaced.
- A single-run or dual-run capacitor is used to store an electrical charge which is then released to power the compressor or fan motor. A defective capacitor will prevent the system from working. You can often tell that a capacitor has failed because it will bulge or leak. You can also use an analog Ohm meter to test the capacitor’s ability to store and release an electrical charge, and a capacitor tester (or a multimeter with a capacitor testing function) to determine if the component has the proper capacitance rating. Before handling the capacitor, you should release the potentially-stored electrical charge by placing a screwdriver blade across each set of terminals. Avoid touching the screwdriver blade when doing this.
- A malfunctioning blower fan motor will prevent the system from cooling as well. The fan blades should rotate freely; if they do not, it’s likely the motor has seized. You can also use a multimeter to determine if the motor is receiving incoming power. If the capacitor is functioning properly and incoming power is present, then the motor windings are probably malfunctioning. This means you will need to replace the blower fan motor with a new one.
Shop Repair Clinic for the right heat pump parts
Whether you need a new blower fan motor, capacitor, or air filter for the heat pump, or just a universal coil cleaner to assist with regular maintenance, RepairClinic.com has what you need. To get started, enter the full model number of the heat pump unit in the Repair Clinic search bar for a complete list of compatible parts. You can then use the “Part Category” filter (Example: “Blower Wheel & Fan Blade”) and “Part Title” filter (Example: “Fan Blade”) to locate the exact replacement part you’re looking for. Repair Clinic stocks heat pump components for all the major heating and cooling brands including Arcoaire, Bryant, Carrier, Coleman, Comfortmaker, Frigidaire, Heil, Payne, Rheem, Trane, and York, but you’ll want to make sure you’re purchasing the part that matches your specific heat pump unit.