How to Maintain a 6–10 Ton Packaged Unit: Filters, Belts, Coils, Gas Heat Exchangers & Seasonal Tune-Ups
If you run a commercial building with a 6–10 ton packaged rooftop or pad-mounted HVAC unit, here’s something Tony will tell you straight:
Commercial equipment doesn’t fail because it’s old. It fails because it’s ignored.
He’s serviced thousands of units on restaurants, gyms, retail stores, medical offices, warehouses, and multi-tenant buildings.
The pattern is always the same:
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Filters clogged
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Belts slipping
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Coils matted with dirt
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Heat exchangers cracked
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Economizers jammed open
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Rooftop ducts leaking
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Drain pans overflowing
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Blowers vibrating
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Gas burners misfiring
Businesses often think maintenance is optional.
But neglecting a 6–10 ton unit is like never changing the oil in a box truck — it WILL break, and it will break at the worst time.
This is Tony’s full, real-world commercial maintenance guide, the same checklist he uses on every job site to keep big packaged units running for 10–20 years.
1. First Rule of Commercial HVAC: Filters Are Non-Negotiable
A 6–10 ton rooftop unit moves 2,100–4,500 CFM of air.
If the filters clog, the entire system suffocates.
Tony sees this every day — filters packed with:
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dust
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pollen
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cardboard fibers
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insulation bits
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grease (restaurants)
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pet hair (veterinary clinics)
✔ Filter Change Frequency
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Every 30 days in restaurants, salons, gyms
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Every 60 days in retail stores/offices
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Every 90 days maximum in clean environments
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Twice monthly during demolition or construction
Bad Filters Cause:
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coil freezing
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blower overheating
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high static pressure
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reduced airflow
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increased energy bills
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compressor stress
Your filters decide how long your system lives.
*(Reference: [Commercial Air Filtration & High-CFM Filter Maintenance Standard])
2. Blower Belts: The Most Ignored Moving Part in Commercial HVAC
Most 6–10 ton units use belt-driven blowers.
If the belt slips, cracks, or stretches, your airflow drops instantly.
Tony checks belts for:
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tension
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cracking
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glazing
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squealing
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pulley alignment
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bearing wear
✔ Belt Replacement Interval
Every 6–12 months depending on runtime.
If belts fail:
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blower slows
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coil freezes
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supply temps rise
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compressor overheats
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duct static skyrockets
Belts cost $10–$40.
Replacing a blower motor costs $600+.
This is the cheapest insurance you can buy.
*(Reference: [Commercial Belt-Driven Blower Maintenance & Alignment Guidelines])
3. Coils: Dirty Coils Kill Efficiency Faster Than Anything
Commercial packaged units have two coils:
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Evaporator coil (indoor)
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Condenser coil (outdoor)
Both must be clean.
Dirty Condenser Coil Symptoms:
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high head pressure
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compressor overheating
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loud operation
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unit short cycling
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20–40% loss in cooling capacity
Dirty Evaporator Coil Symptoms:
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weak airflow
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coil frosting
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musty odors
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low supply air temperature
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high humidity
✔ Coil Cleaning Frequency
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Twice per year for rooftop equipment
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Quarterly if near kitchens or dusty roads
Tony uses fin combs, coil cleaner, and low-pressure washing.
Anything else bends fins and destroys capacity.
*(Reference: [Commercial Coil Cleaning])
4. Gas Heat Exchanger: The Most Critical Safety Component
If your 6–10 ton unit uses gas heat, the heat exchanger must be inspected annually.
Tony checks for:
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cracks
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rust
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hotspots
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flame rollout
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improper burner ignition
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flue blockage
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CO leakage risk
A cracked exchanger turns your HVAC system into a carbon monoxide hazard.
Gas Components Tony Inspects:
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burners
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flame sensor
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igniter
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manifold pressure
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combustion air
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venting integrity
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rollout switches
If heat exchangers are ignored, failures are inevitable — and dangerous.
*(Reference: [Commercial Gas Furnace Heat Exchanger Safety Inspection Standard])
5. Blower Assembly: The Heart of the Entire System
Commercial blowers are massive and critical.
Tony inspects:
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wheel cleanliness
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shaft alignment
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set screw tightness
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bearing lubrication
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motor amperage
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blower wheel balance
A blower wheel coated in dust throws the motor off balance and sends vibration through the entire system.
Blower cleaning alone can reduce energy usage by 10–15%.
6. Electrical Components: Loose Connections = Fire Risk
Commercial units vibrate constantly.
Over time, electrical terminals loosen.
Tony checks:
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contactors
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relays
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capacitor health
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wire insulation
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screw terminals
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disconnect box
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phase balance on three-phase units
Loose wires cause:
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arcing
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overheated breakers
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burned contactors
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compressor failure
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blower failure
A five-minute electrical check can prevent a $5,000 repair.
*(Reference: [Commercial HVAC Electrical Safety])
7. Economizers: The Most Common Source of Hidden Problems
Economizers save money — when they work.
Most are broken or misconfigured.
Tony checks:
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outdoor air sensor
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mixed air sensor
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damper blade movement
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actuator response
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minimum position setpoints
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linkage alignment
Economizers stuck partially open drag in hot, humid air 24/7, tank efficiency, overload cooling cycles, and create comfort complaints.
Proper economizer calibration is essential.
8. Condensate Drainage: Small Problem, Big Damage
Blocked drains on commercial units cause:
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roof puddles
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indoor leaks
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mold
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rusted pans
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electrical shorts
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blown fuses
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unit shutdown
Tony checks:
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trap height
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drain slope
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algae growth
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debris blockage
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cracked PVC
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insulation coverage
He vacuums out lines and disinfects every drain twice per year.
9. Seasonal Maintenance: What to Do Every Spring, Summer, Fall & Winter
Commercial packaged units need a different checklist each season.
SPRING (Cooling Prep)
✔ change filters
✔ clean condenser coil
✔ verify blower belt tension
✔ check economizer operation
✔ measure static pressure
✔ test compressor amp draw
✔ calibrate thermostats
✔ clear all drains
SUMMER (Peak Heat Load)
✔ inspect condenser coil weekly (restaurants)
✔ monitor supply air temperature
✔ measure subcooling/superheat
✔ ensure economizer is not stuck
✔ verify proper staging
✔ check rooftop duct insulation
FALL (Heating Prep)
✔ inspect gas heat exchanger
✔ clean burners and flame sensor
✔ test ignition sequence
✔ check rollout safeguards
✔ verify temperature rise
✔ inspect supply and return plenums
WINTER (Freeze Protection)
✔ protect drains from freezing
✔ check belts (cold seasons cause slip)
✔ examine heat pump defrost cycles
✔ inspect curb insulation
✔ verify economizer closure
✔ monitor vibration in high winds
Seasonal maintenance prevents seasonal breakdowns.
10. Why Restaurants, Gyms & Retail Stores Need Extra Maintenance
Restaurants
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grease infiltrates filters
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rooftop locations near exhaust hoods
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long runtimes
Tony recommends monthly coil checks.
Gyms
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very high humidity
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high occupancy
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heavy return demand
Filters clog twice as fast.
Retail Stores
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large glass storefronts
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varying heat load
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long open hours
Economizer calibration is crucial.
Different businesses need different maintenance intensity.
11. Signs Your 6–10 Ton Unit Hasn’t Been Maintained Properly
Tony knows maintenance neglect when he sees:
❌ Short cycles
❌ Loud vibration
❌ Warm supply air
❌ Musty odors
❌ Uneven temperatures
❌ Rising energy bills
❌ Frozen coils
❌ Gas burner delays
❌ Blower belt squealing
❌ Rusting heat exchanger
❌ Drain pan overflow
These aren’t “normal commercial problems.”
They’re maintenance failure symptoms.
12. The Cost of NOT Maintaining a Commercial Unit
Here’s what business owners end up paying:
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Compressor replacement: $2,000–$5,000
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Blower motor replacement: $600–$1,500
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Heat exchanger replacement: $1,200–$3,500
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Economizer repair: $350–$900
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Coil cleaning labor: $300–$800
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Full unit replacement: $9,000–$22,000+
Maintenance: $350–$650 twice a year
Neglect: 10x more expensive
Tony has never seen one ignored unit survive more than 7–9 years.
Maintained units last 15–20+ years.
Tony’s Final Verdict on Commercial Maintenance
Here’s Tony’s take:
✔ Filters matter
✔ Belts matter
✔ Coils matter
✔ Gas heat safety matters
✔ Electrical connections matter
✔ Economizer tuning matters
✔ Drainage matters
✔ Seasonal tune-ups matter
✔ Maintenance saves money
✔ Neglect destroys equipment
A 6–10 ton packaged unit is a workhorse —
but only if you treat it like one.
Commercial HVAC is simple:
Take care of it, and it takes care of your building.
Ignore it, and it fails when you need it most.
Tony’s field-tested diagnostic checklist is provided in the next blog.
