In hot, dry climates like Arizona, heat pumps are by far the most effective and energy-efficient way of cooling and heating your home. As with any other type of HVAC unit, a heat pump can potentially suffer from a variety of different issues that can affect how well it works or potentially cause it to not run at all. If you can’t get your heat pump to turn on, here are some common reasons this happens and how they can be fixed.
If your heat pump won’t turn on when needed, the first thing you’ll want to do is check your thermostat. Make sure that you have the thermostat set to heat or cool and that the temperature is set to where it should be. You’ll also want to make sure that the thermostat isn’t showing a low battery alert. If the batteries are completely dead, nothing will show up on the thermostat display. The display will usually still work if the batteries are low, but they may still not have enough power to enable the thermostat to send the signal for the heat pump to turn on.
If the thermostat is set correctly and the heat pump still won’t turn on, it could be that the thermostat is malfunctioning or not calibrated properly. These issues can cause the thermostat to either not show the correct indoor temperature or not be able to read the temperature accurately. There may also be an issue with the wiring in between the thermostat and the heat pump, which makes it so that the signal never reaches the heat pump. The only way to know if any of these issues are causing your heat pump to not turn on is to have your thermostat inspected and serviced.
Power Loss and Electrical Problems
If the thermostat is set correctly, the next thing you’ll want to check is whether the heat pump still has power. One of the most common reasons why heat pumps won’t turn on is due to a loss of power, and this can happen because a power surge or some other issue caused the circuit breaker that controls the heat pump to trip.
Even if the circuit breaker isn’t tripped, you can try to reset the system to see if it will then turn on. This is done by simply shutting the breaker off and then turning it back on. If the heat pump still won’t turn on, there may be an issue with the electrical wiring. It might be that one of the connections is loose and needs to be tightened. The problem could also be related to a short or fault in the control board that is preventing the unit from turning on.
There are also a few different issues that can cause a heat pump to continually trip the circuit breaker whenever it tries to start. This most commonly happens because the fan motor or compressor motor has burnt out. It’s also possible that a frayed wire is causing the unit to short-circuit.
The fan motor is fairly easy to replace, but a burnt-out compressor motor will usually mean you need to have your heat pump replaced. This motor can be replaced, but the cost of doing so is usually about the same as the cost of purchasing and installing a whole new unit. For this reason, replacing the compressor motor generally only ever makes sense if the heat pump is only a few years old and still under warranty.
Malfunctioning Reversing Valve
The reversing valve is the thing that makes heat pumps different from air conditioners. In an air conditioner, the refrigerant can only flow in one direction to remove heat from the house. The reversing valve enables the heat pump to switch the direction of the refrigerant flow so that it can absorb heat from outside and transfer it into the building.
The reversing valve can sometimes fail or get worn out, and this will prevent the heat pump from being able to change the direction of the refrigerant flow. If the valve fails, it won’t cause any issues until you try to switch the system over from cooling to heating or vice versa. Once you do switch, the heat pump will fail to turn on since the reversing valve can’t activate and switch from cooling to heating.
This is something that you can easily check on your own. To do so, change your thermostat to cooling mode to see if the heat pump will now turn on. If it turns on in one mode but not the other, it is a sure sign that the reversing valve isn’t working and needs to be replaced.
Heat pumps and all other HVAC units require a huge amount of power to start. This power draw is so great that your electrical system cannot provide it on its own. To overcome this problem, all HVAC units have what is known as a start capacitor. The capacitor works by storing a powerful electric charge. Whenever the heat pump needs to turn on, the capacitor instantly releases the charge to essentially jump-start the unit’s motors.
Heat pump capacitors can wear out due to age or fail for a variety of different reasons. If the capacitor fails, there won’t be enough power and the heat pump may not start. In most cases, a failed capacitor will result in the heat pump making audible clicking noises whenever it tries to start. If you hear this sound, it indicates that you need to hire an HVAC technician to replace the capacitor. This is definitely not something you should ever attempt on your own due to both the potential for electrocution and the risk of further damaging your heat pump.
Blower Fan Issues
Issues with the blower fan inside your house can also cause the heat pump to fail to turn on. Whenever heating or cooling is needed, the thermostat signals both the heat pump and the blower fan to turn on. If the blower fan doesn’t turn on for any reason, it will either prevent the heat pump from starting or cause it to turn off almost immediately.
Most commonly this occurs either due to wiring issues or because the fan motor is burnt out and needs to be replaced. The issue can also occur due to a bad start capacitor. Most heat pumps have a three-way capacitor that works to provide a charge to the compressor motor, heat pump fan motor and blower fan motor. However, some systems have two capacitors—one inside the heat pump that powers its two motors and another capacitor inside the home that provides a charge to the blower fan motor.
If your heat pump won’t turn on, the expert technicians at Honest Air Conditioning can inspect the unit and your entire HVAC system to diagnose and then repair the problem. We service and repair all brands and models of heat pumps, and we can also help with heat pump installation and replacement. Our team also installs, repairs and maintains air conditioners, furnaces and a range of indoor air quality equipment. We offer services for customers in Mesa and the surrounding areas. Contact us today to learn more.