In the commercial HVAC/R industry, remanufactured compressors are a reliable and cost-effective alternative to new units—especially when turnaround time, availability, and budget are all pressing concerns. As a technician, you know that keeping a system online doesn’t just depend on the quality of the replacement compressor—it’s about how that compressor is cared for after it’s installed.
Whether you’re dealing with a Copeland scroll, a Bitzer semi-hermetic, or a Carrier screw, every compressor has one thing in common: its lifespan is directly tied to the system it operates within. Even the most rigorously remanufactured unit won’t survive long if the environment around it is full of neglect.
Let’s walk through some proven maintenance tips and lesser-known best practices that can extend the life of your remanufactured compressor and keep your clients’ systems running strong.
1. Cleanliness Is Not Optional—It’s Mandatory
The number one killer of remanufactured compressors? Contamination.
Debris, acid, moisture, and sludge are all silent assassins hiding in poorly flushed systems. When you’re replacing a failed compressor, that failure usually doesn’t happen in isolation. You need to ask why the original compressor failed—because if it was a burnout or lubrication-related issue, those contaminants are likely still lurking in the system.
Your must-do checklist:
- Flush all lines and coils thoroughly.
- Replace the filter-drier—don’t even think about reusing the old one.
- Install a suction line filter if the original failure involved a burnout.
- Pull a deep vacuum (500 microns or less) and verify with a decay test.
These aren’t just good practices—they’re non-negotiables if you want your newly reman compressor to survive past the warranty period.
2. Oil Management: Don’t Assume It’s Right
Every remanufacturer fills their compressors with oil, but that doesn’t mean the oil level, type, or compatibility is perfect for the application you’re servicing. When you purchase one from Compressors Unlimited, we will advise you of the proper oil type for future reference.
Before firing up the system:
- Check oil type. POE, mineral, and alkylbenzene oils don’t mix well. Make sure the system’s refrigerant and oil are compatible.
- Verify oil level. For semi-hermetics, use the sight glass. For scrolls and hermetics, trust your scale and service records.
- Know your history. If the system has had multiple refrigerant top-offs or a history of oil return issues, assume you need to investigate further.
Pro tip: If you’re dealing with a long-line application or a system with oil separators, consider adding a sight glass in the return line and monitor oil migration.
3. Balance the Charge: Superheat and Subcooling Matter More Than You Think
A lot of techs focus on getting the suction pressure and head pressure in range, but forget the golden rules of heat transfer—superheat and subcooling. These are the pulse and blood pressure of your system.
Too little superheat? You’re flooding the compressor with liquid refrigerant, which leads to oil dilution and, eventually, valve failure or scroll set damage.
Too much superheat? The compressor runs hot, struggles to cool its windings, and oil starts to break down.
Low subcooling? You’re undercharged, which affects capacity and causes high suction to superheat.
High subcooling? You’re likely overcharged, causing high head pressure and excessive compressor workload.
Get these in range, and your remanufactured compressor will thank you with years of service, at least 8-10 years of cooling.
4. Monitor Amp Draw and Voltage Like a Hawk
High amp draw kills compressors slowly. Low voltage does it even faster.
Before signing off on a job, always:
- Verify voltage under load at the compressor terminals (not just at the disconnect).
- Measure LRA and compare to the data plate—big gaps could mean worn internal components or starting issues.
- Use a clamp meter and record running amps under typical conditions. Monitor for imbalances over time.
- Check for voltage imbalance on three-phase units. More than a 2% imbalance? You’re on borrowed time.
A common cause of premature failure in reman units is a power issue that was never caught because no one checked the phase balance or voltage drop under load. Don’t be that guy.
5. Airflow and Heat Exchange: The Hidden Longevity Factor
Your compressor depends on heat exchange working correctly on both sides of the system. Condensers packed with pollen (tough problem in the southern states of the USA), evaporators caked with grease, or plugged microchannel coils? That compressor’s running hotter than it should.
If the system has poor airflow:
- Head pressure rises.
- Return gas gets too hot or too cold.
- Oil thins out or doesn’t return properly.
- The compressor operates under higher stress every minute it runs.
Best practice? Clean coils thoroughly (not just a very basic rinse-off), check blower motor operation and verify delta T across evaporators and condensers.
6. Don’t Ignore the Crankcase Heater
Most techs know crankcase heaters are installed to prevent refrigerant migration—but too often they assume it’s working just because it’s there. Always double check that the heater is working correctly because even brand new parts can fail.
Here’s how to check:
- Measure amp draw (should match spec).
- Feel the compressor body—it should be warm, not hot, before startup.
- Replace any questionable heaters during compressor swap-outs.
Failing to energize the crankcase heater at least 12 hours before startup on a cold system can destroy a reman compressor before it even gets going.
7. Soft Starts and Hard Starts—Pick Your Weapon Wisely
Reman commercial hvac/r compressors—especially scrolls—can have higher internal friction at startup due to tighter tolerances or initial oil distribution. Depending on your application, you might benefit from:
- Hard start kits (start capacitors and relays) on single-phase scrolls with marginal voltage.
- Soft start modules or VFDs on larger semi-hermetics to prevent torque shock.
If your commercial HVAC/R compressor frequently fails at startup or trips on thermal overload, your solution might not be inside the compressor—it might be in how it’s starting.
8. Log Your Work and Recheck After 24 Hours
One of the best things you can do for a reman compressor is revisit the system after 24 hours of operation—or at least coach your service team to do it.
On return visits:
- Recheck superheat, subcooling, and suction line temperature.
- Inspect for abnormal vibrations or noises.
- Verify the crankcase heater function again.
- Confirm oil return and inspect for foaming.
Many issues that would go unnoticed on day one will become obvious with a second look. And catching them early makes all the difference in keeping your reman commercial HVAC/R compressor alive.
9. Understand the Difference Between “Runs” and “Runs Right”
It’s not enough to say “the compressor is running.” You want it running in spec, with minimal stress and optimal conditions.
Quick checklist for a healthy, long-living reman unit:
- Suction pressure in range based on system design.
- Discharge line temperature under 225°F.
- Voltage within 5% of rated values.
- Amp draw within ±10% of nameplate rating.
- No unusual noises, pulsation, or harmonics.
- Oil level is consistent and clear (on units with sight glass).
If everything checks out, now you can say it’s “running right.”
10. Partner With a Remanufacturer That Has Your Back
Let’s be real—no compressor lasts forever. But when something goes sideways, you need a remanufacturer who supports technicians in the field.
Choose suppliers that:
- Pre-fill compressors with the correct oil for the application.
- Offer real technical support from experienced HVAC/R pros.
- Provide clear warranty guidelines—and honor them when you’ve done the job right.
- Share documentation, specs, and training for their units.
The best reman compressors are more than just rebuilt—they’re reborn with better QC, testing, and upgrades. When paired with good maintenance, they often outlive the OEM unit they replaced. In case you are wondering, the remanufacturing team you need is Compressors Unlimited. We’ve got your back from start to finish.
Advice From a Seasoned HVAC/R Commercial Compressor Remanufacturer
Keeping a remanufactured compressor alive and thriving is a mix of mechanical knowledge, electrical awareness, and solid fundamentals. If you treat the system holistically—addressing airflow, charge, oil, power quality, and contamination—you’ll turn what some see as a “temporary fix” into a long-term solution.
Good techs get the system running. Great techs keep it running. And those extra 30 minutes you spend verifying the small things? That’s the difference between a callback and a reputation for bulletproof installs.
