When the temps tank and customers start calling because their house just turned into a walk-in freezer, heat pump season officially begins.
And if you’re in the HVAC trenches, you know heat pumps love to act up at the absolute worst time: early morning, late night or right when you’ve finally sat down with a plate of something warm. So here’s a winter survival guide, packed with the must-check steps that’ll help you troubleshoot heat pump issues fast and keep the callbacks to a minimum.

Start with the Simple Stuff (Seriously)

Look, even pros get burned by the basics. So before you dive elbows-deep into a system:

  • Is the thermostat set correctly?
  • Are the breakers on?
  • Are the filters clear?
  • Was the outdoor unit buried under six inches of last night’s snow?

A clogged filter or iced-over condenser can make a perfectly fine heat pump look like it’s ready for hospice care. So knock out the easy wins first: They save time and keep you looking like a hero.

That Outdoor Unit Needs Breathing Room

Cold weather means two things: defrost cycles and frost buildup. If airflow is blocked, the unit starts acting possessed -- running long cycles, blowing cold air or shutting down completely. Clear snow, clean off ice (gently, no ice picks unless you want an unplanned refrigerant shower) and make sure water from the roof isn’t dripping straight onto the unit and freezing.

Check the Defrost Cycle, That Silent Trouble Starter

A lot of winter heat pump complaints come down to one thing: defrost cycle issues. Keep an eye on:

  • Defrost sensor operation
  • Control board signals
  • Outdoor coil temperature
  • Reversing valve function

If the defrost cycle isn’t triggering, your customer’s outdoor unit is basically wearing a parka made of ice. And no, heat pumps aren’t big fans of frost fashion.

Refrigerant Issues: The Classic Culprit

Low charge, overcharge or a small leak? Pick your poison, because all three will ruin heating performance. In winter, the symptoms get loud:

  • Low outlet temps
  • Long run times
  • Ice buildup
  • That “my heat pump never shuts off” customer voice

Don’t skip your superheat/subcool checks. A smart diagnosis saves you from swapping parts that aren’t the real problem.

Electric Heat Strips: The Backup That Bails You Out

When temperatures drop too far, electric heat strips step in like a reliable backup quarterback. But if they’re not working, you’re gonna hear about it. Check:

  • Sequencers
  • Limit switches
  • Airflow
  • Wiring connections

A dead heat strip will make a fully functional heat pump look useless on the coldest day of the year.

Winter-Proof the System Before You Leave

Want fewer callbacks? Do the small stuff:

  • Tighten connections
  • Clear drain paths
  • Check insulation on refrigerant lines
  • Educate the homeowner on what’s normal in cold weather (yes, steam from the outdoor unit is fine)

These little touches save you trips and keep customers calm instead of panicked.

Overall, heat pumps can be quirky when it’s cold out, but with the right checks, you’ll diagnose faster, fix smarter and stay one step ahead of winter chaos. So suit up, stay sharp and remember: When the calls start coming in hot, we have both the parts and support to keep you running.

Now, let’s keep those houses warm and the callbacks low.