5 Top Heat Pump Problems You'll Face After HVAC College


An HVAC technician installs a new heat pump (image courtesy of Atel Air)

Thinking about enrolling in HVAC college, and want to know more about the heating, ventilation, and air conditioning problems you'll learn about in training—and tackle during your career?

In this post, we break down five of the most common heat pump issues HVAC technicians get called on to diagnose and repair.  Take a look at the troubleshooting challenges you'll face on-the-job, and the most likely causes of each malfunction.


1. The Heat Pump Ices Up & Won't Defrost

This is a typical winter-time heat pump issue. Under normal conditions, the unit will go into defrost mode and take care of the problem automatically; but if this doesn't happen, ice will build up quickly and cause serious damage.

If the heat pump gets totally encased in ice, the process of heat transfer between the refrigerant and the outside air won't work. And if ice gets inside the coils it can damage the fins and fan blades, eventually leading to compressor failure.

What's the root of the problem?

An HVAC technician will look at several possible causes of heat pump icing. The defrost malfunction could be caused by faulty relays, controls, censors, or the reverse valve that switches the unit from heat to air conditioning mode.

The fan motor might be damaged, or there may be a refrigerant leak—making it impossible for the unit to produce enough heat to melt the ice. The technician will troubleshoot each of these common causes to uncover the culprit of an iced-up unit.


2. The Heat Pump Doesn't Heat or Cool Properly

If it's significantly cold or hot outside, this problem will definitely prompt an urgent service call! A heat pump that doesn't heat or cool properly is likely affected by one (or more) of the following four issues:

  • blocked air ducts
  • clogged air filter
  • poor refrigerant flow
  • faulty valves
  • dirty unit

In general, clogged filters, leaky ductwork, dirty thermostats, and sooty flues can reduce heat pump efficiency by as much 25%. HVAC technicians will check and service these components during the yearly maintenance visit, which should be enough to keep the system running at peak throughout the year.


3. The Heat Pump Makes Strange & Unusual Sounds

A little bit of noise is normal for heat pumps. But strange and unusual rattling, squealing, or grinding should be attended to quickly by a professional. If you get called in to diagnose a noisy unity after HVAC training, some of the first items on your troubleshooting checklist will be:

  • ensure the control panel is screwed tightly into place
  • check the bearings in the motor
  • check for loose ductwork or register out of place


4. The Heat Pump Won't Even Turn On

This one's sure to cause the homeowner some stress and frustration! If the unit won't turn on, an electrical problem is most likely to blame. The HVAC technician will rule out obvious causes by ensuring the unit is actually getting power, and resetting the circuit breaker.

It is also wise to check the thermostat, and see if there are any frayed wires around the heat pump or air handler, or other signs of wear and corrosion. HVAC courses include the fundamentals of electricity theory, safety, and practice—so you'll be prepared to address basic electrical issues that cause system failure.


5. The Heat Pump Keeps Turning Off and On

Otherwise known as "shortcycling", a heat pump that constantly turns off and on is annoying for the homeowner, and bad for the unit. What are the most likely causes of shortcycling?

The HVAC technician will check for leaks (open windows, cracks under doors, etc.) through which heated air is escaping. He or she will also examine the thermostat for a bad circuit or malfunctioning heat anticipator.

The heat pump could also be over-heating, because of a clogged air filter. It's also quite possible that the thermostat has been poorly calibrated, or placed in a drafty, overly cool location. Other likely causes include a refrigerant leak or compressor damage.

It's vital to root out the cause of shortcycling quickly, because frequently turning off and on forces the heat pump components to work harder, and require more frequent repairs. Left unchecked, this problem could shorten the life of the unit by several years—and cost the homeowner more in energy bills.

Have another common heat pump problem to add to the list? Tell us about it in the comments.

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