Solid ice on the outdoor unit
A little frost in winter is normal — a solid block of ice is not. If the defrost cycle isn’t clearing it, something is wrong with the defrost board, sensors, or refrigerant charge.
Heat Pump Repair
Heat Pump Repair in Sumter, SC
Heat pump repairs need a specialist. Since heat pumps provide both heating and cooling, every repair should include testing both operating modes, verifying reversing valve operation, and confirming the defrost cycle works correctly. That’s exactly how our technicians diagnose every call.
Repair cost approaching replacement? Ask about financing.
Both Modes. One Diagnosis.
See how we approach every call →
A heat pump isn’t just an AC that runs in reverse.
The refrigerant cycle changes direction with the seasons. The defrost cycle kicks in on its own schedule. Auxiliary heat strips act as a backup—not a primary heat source. An HVAC technician who only tests the cooling mode is seeing only half the system. We test heat pumps in both heating and cooling modes, verify reversing valve operation, and confirm the defrost sequence before we name the problem.
We service every major residential heat pump brand, including Tempstar, Carrier, Trane, Lennox, Goodman, Rheem, Mitsubishi, and more. Every repair recommendation is explained in writing before work begins, and if replacement makes better long-term financial sense, we’ll show you why before you spend the money.
Common Heat Pump Calls
What to expect during a heat pump repair call
Heat pump symptoms can look like AC problems or furnace problems — the diagnosis requires testing both sides.
AUX heat running on mild days
That “AUX” light shouldn’t stay lit when it’s 50°F outside. Refrigerant charge, reversing valve, or defrost issue is making the heat pump underperform.
Won't switch heating/cooling modes
Reversing valve failure — the component that switches the refrigerant direction between seasons. Usually a solenoid or valve body issue.
Blowing lukewarm air
Air coming out at body temperature instead of warm or cool means the system isn’t moving heat effectively. Low charge, failing compressor, or restricted airflow.
Fan blade spinning, compressor not
You can hear the compressor humming but the fan is still — or vice versa. Usually a capacitor, contactor, or motor issue on the affected component.
Short-cycling
Cycling every few minutes burns out compressors fast. Usually a low refrigerant charge, a thermostat issue, or an oversized system.
Recognize any of these? Let’s find the real problem before you pay for the wrong repair.
Our Process
What happens when you call about a heat pump — five steps
Both sides of the refrigerant cycle tested before a repair is quoted.
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Same-day scheduling
Call or request online. Same-day if a slot is open, next-day at the latest for non-emergencies.
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Full-cycle diagnostics
We run the unit in heating and cooling, check refrigerant in both directions, verify the reversing valve, and confirm defrost cycles correctly.
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Written options
Repair price, alternatives, and our recommendation in writing — before any work starts.
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Same-day repair
Most heat pump repairs wrap the same day.
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Post-repair verification
Before leaving, we re-test in the failing mode and confirm temperature split, pressures, and amperage all in spec.
Why homeowners call Advance for heat pump work
Both modes tested. Every time.
- NATE-certified technicians trained in heat pump diagnostics — not just cooling
- All brands — Tempstar® , Carrier, Trane, Mitsubishi, Goodman, and more
- Reversing valve, defrost board, and refrigerant system tested in both modes
- Repair price in writing before any work starts
- Same-day on most weekday calls; 24/7 emergency dispatch
- Family-owned since 1986 — we live here, we’re accountable here
Heat pump repair or replace: how to think about it
Honest framing — not a push toward the bigger ticket.
- Under 10 years old — repair almost always makes sense unless it’s the compressor
- 10–15 years old — weigh repair cost against system efficiency and remaining life
- Over 15 years old — if repair exceeds ⅓ of replacement cost, replacement usually wins
- Compressor replacement — often $2,500+; worth running replacement math first
- Refrigerant type — R-22 systems needing a recharge are strong replacement candidates
- We show you the math — payback period, current efficiency vs. new, financing
Frequently Asked
Heat pump questions, answered straight.
Why is my heat pump running but not heating my home?
A heat pump that’s running but not producing enough heat may have a reversing valve issue, low refrigerant, a defrost cycle problem, restricted airflow, or a malfunctioning auxiliary heat system. Because several different components can cause similar symptoms, a complete diagnosis is the best way to identify the actual problem before replacing parts unnecessarily.
Is frost on the outdoor coil normal?
A little frost on the outdoor coil is normal in cold, damp weather — your unit will run a brief defrost cycle every 30–90 minutes to clear it. That’s by design. What’s not normal: a solid block of ice covering the unit, ice that doesn’t clear between cycles, or a coil that ices up in 50°+ temperatures. Those are service calls.
What is AUX heat and when should it run?
AUX (auxiliary) heat is your backup — resistance heating strips that kick in when the heat pump alone can’t keep up, typically below 35–40°F. It’s expensive to run because it uses straight electric resistance. Seeing “AUX” on a mildly cool day (above 45°F) is a sign something is wrong with the heat pump itself.
My AUX heat is running in mild weather. What’s wrong?
Something is wrong: likely a refrigerant charge issue, a reversing valve problem, a faulty defrost board, or a thermostat misconfiguration. Any of these causes the heat pump to underperform in heating mode, triggering the aux strips unnecessarily. You’ll often see it on your power bill before you notice it on the thermostat.
How much do heat pump repairs cost?
Capacitors, contactors, and defrost boards typically run $200–$500 installed. Reversing valves and TXVs usually land in the $700–$1,400 range. Compressor replacement starts around $2,500 and often makes a replacement conversation worthwhile on older units.
Can a heat pump handle Sumter winters?
Yes — modern heat pumps are efficient and effective down to 25–30°F in standard configurations. Mitsubishi Hyper-Heat models maintain full heating capacity to 5°F, which is well below what Sumter typically sees. If your heat pump is struggling in mild winter weather, the issue is usually the system, not the technology.
How do you test a heat pump?
We run the unit in both heating and cooling mode, check refrigerant pressures and temperatures in both directions, verify the reversing valve switches correctly, confirm the defrost cycle triggers and clears on schedule, and test auxiliary heat staging. A heat pump that only gets tested on one side of the cycle is only half-diagnosed.
Financing & Payment Options
Flexible Financing for Repairs, Replacements & New Systems
HVAC investments shouldn't put your comfort on hold. We work with qualifying customers to spread the cost of repairs, replacements, and indoor air quality upgrades into manageable monthly payments.
Big repair or right-sized replacement — financing available either way. Compressor replacements and full system replacements qualify for financing. Soft pre-qual in minutes.
Subject to credit approval. Financing options, terms, and qualifications may vary by lender and project type. Not all applicants will qualify. Our team can walk you through available options when you request service or an estimate.
Heat pump back on
Both modes tested. Problem found.
NATE-certified diagnostics, all brands, repair options in writing before any work starts. Call (803) 481-8200 — live answering 24/7.