0 comments

Maintenance Checklist for Your Daikin 10 Ton RTU: What to Do Each Season (Tony’s Pro-Level Guide)

A 10-ton rooftop unit is one of the hardest-working pieces of equipment in any commercial building. Whether you’re running a retail store, a small office, a warehouse, a restaurant, or anything in-between, your RTU is the reason your building doesn’t turn into a sauna, a freezer, or a humidity swamp.

But here’s the blunt reality Tony has learned over decades of rooftop crawling:

Commercial HVAC systems don’t fail from “bad luck.” They fail from “bad maintenance.”

And the Daikin 10 Ton 15 IEER2 packaged unit is no different.
Daikin builds tough equipment. Durable equipment. Efficient equipment.
But no rooftop unit is invincible—not when it’s sitting on a roof getting roasted by the sun, blasted by wind, filled with dust, and forced to run for thousands of hours every year.

That’s why a seasonal maintenance checklist isn’t optional.
It’s the difference between:

✔ A 15–20 year lifespan
and
✘ A 7–10 year burnout disaster

Today, I’m giving you the real commercial maintenance plan—Tony style.
Not the watered-down “change your filters” brochure.
The actual checklist your building needs to keep that Daikin running efficiently, quietly, safely, and for as long as possible.

Let’s get into it.

Why Seasonal Maintenance Matters More Than You Think

Most building owners only call HVAC techs when:

The AC stops cooling
The heat stops heating
The unit starts making weird noises
Tenants or staff start complaining
Utility bills spike
Water starts leaking inside
Breakers trip
Rooftop equipment freezes over

By that time, the damage is often already done.

Commercial rooftop units aren’t complicated when you understand one thing:

“HVAC systems don’t die suddenly. They die slowly, over years, when nobody’s paying attention.”

Coils get dirtier.
Airflow drops.
Belts loosen.
Motors strain.
Economizers malfunction.
Electrical connections burn out.
Refrigerant conditions drift.
And the unit has to work harder to produce the same cooling.

Maintenance is simply reversing that slow death before it becomes a failure.

Here’s a reference for long-term equipment degradation behavior:
[Commercial HVAC Wear & Performance Trends]

Spring Maintenance Checklist (Cooling Season Prep)

Spring is the most important maintenance period of the entire year.
If you skip spring maintenance, you’re gambling with your summer.

Here’s Tony’s complete spring checklist:

1. Clean the Condenser Coil Thoroughly

Not “sort of.”
Not “spray and pray.”

A rooftop condenser coil needs:

Foam cleaner
Pressure rinse
Full fin exposure
Debris removal
Straightened bent fins

Dirty coils cause:

High head pressure
Compressor failures
Higher energy bills
Capacity loss
Shortened lifespan

I’ve seen 30% cooling loss from dirty coils. No exaggeration.

2. Inspect & Clean the Evaporator Coil

This one is often overlooked because it’s “inside the unit.”
Don’t ignore it.

Dirty evaporator coils cause:

Coil freezing
Poor cooling
Water overflow
Mold growth
Reduced airflow

Here’s a coil hygiene concept:
[Evaporator Coil Cleaning Principles]

3. Replace Air Filters

Airflow is life.
A cheap filter is the cheapest insurance policy in HVAC.

Replace filters:

Monthly for restaurants
Monthly to bi-monthly for gyms
Every 2–3 months for offices
Every quarter for warehouses

If filters look dirty? Replace immediately.

4. Inspect Fan Motors & Bearings

Problems you’ll catch early:

Bearing wear
Motor overheating
Shaft play
Fan imbalance
Motor noise

A failing fan motor can drag down efficiency for months before dying.

5. Inspect Belts & Pulleys

A loose or cracked belt causes:

Poor airflow
Noise
Excessive motor strain
Fire risk in extreme cases

Replace belts every 1–2 years, or sooner if they squeal.

6. Check Refrigerant Performance (Not Just Pressures)

A good tech checks:

Superheat
Subcooling
Evaporating temperature
Condensing temperature
Line temperatures
Sight lines for oil
Compressor amps

Incorrect refrigerant levels quietly destroy compressors over time.

[Refrigerant Performance Evaluation Methods]

7. Inspect Economizer Operation

95% of economizers I’ve checked over the years were not working right.

Check:

Damper movement
Actuator operation
Sensor calibration
Outdoor air temperature sensors
Minimum position settings

A stuck-open economizer can add tons of extra load.

8. Tighten Electrical Connections

Loose electrical lugs cause:

Burned contactors
Failed boards
Blower shutdowns
Compressor damage
High resistance that raises amp draw

Tony rule: tighten every screw.

9. Inspect the Roof Around the Unit

A leaking or weak curb can:

Damage the building
Rot the roof
Cause mold growth
Destroy the RTU base

Check:

Flashing
Sealant
Curb insulation
Attachment points

This is non-negotiable.

Summer Maintenance Checklist (High Load Season)

Summer is where your Daikin earns its paycheck.
The unit will run harder, longer, and hotter than any other time of year.

1. Visual Checks Every Month

Look for:

Ice buildup
Dirt accumulation
Debris blocking the coil
Sagging panels
Loud noises
Uneven cooling complaints

2. Clean the Condenser Coil Again (If Needed)

A mid-summer coil rinse can dramatically improve performance.

I’ve saved restaurants thousands during heatwaves just by rinsing clogged coils.

3. Verify Fan Speeds & Blower Performance

High heat stresses:

Blowers
Belts
Motors
Bearings

A weak blower equals weak cooling—period.

4. Measure Delta T (Temperature Split)

Ideal cooling temp split:

18°F–22°F

More?
May indicate restricted airflow.

Less?
May indicate refrigerant issues or coils clogged.

Fall Maintenance Checklist (Heating Prep + End of Cooling Season)

Fall is your chance to fix anything summer damaged.

1. Deep Clean the Coils (Both Sides)

Cooling season dirt piles up—remove it before winter.

2. Furnace Inspection (If Gas Heat)

Check:

Burners
Flame sensors
Igniters
Heat exchanger
Gas pressure
Venting
Safeties

Gas issues can be dangerous and costly.

3. Inspect Electrical After Heavy Runtime

Heat expands metal.
Long runtimes cause wear.
Connections loosen.

Fall tightening is essential.

Here’s a seasonal electrical inspection reference:
[HVAC Electrical Fatigue Patterns]

4. Verify Economizer Seal

Winter air infiltration is bad for heating bills.

5. Check The Roof for Damage

Summer storms beat up commercial roofs:

Loose flashing
Curb lift
Sealant cracks
Water pooling

Fix roof issues early.

Winter Maintenance Checklist (Low Load + Freeze Protection)

Winter is easier on cooling components but brutal in different ways.

1. Inspect the Heat Exchanger

DANGER zone if cracked:

Carbon monoxide
Poor heat output
Inefficiency
Shutdowns

Replace at first sign of cracking.

2. Test Defrost Cycle (If Heat Pump)

A malfunctioning defrost will freeze the coil into a block of ice.

3. Clear Snow & Ice From Around the Unit

Snowdrifts clog airflow.
Ice buildup stresses fan motors.

4. Inspect Drain Pans & Lines

Frozen drains = flooding during thaw cycles.

5. Reduce Fresh Air Intake

Too much outside air = wasted heating energy.

Annual Maintenance (Tony’s Deep-Dive List)

Once per year, your Daikin should get the full inspection, including:

✔ Full coil cleaning

✔ Complete electrical inspection

✔ Refrigerant performance analysis

✔ Duct static pressure test

✔ Motor amperage testing

✔ Fan balancing

✔ Belt replacement

✔ Economizer calibration

✔ Gas pressure tuning

✔ Roof sealing inspection

✔ Drain cleaning

✔ Full airflow measurement

✔ AHU interior cleaning

✔ Panel tightening

✔ Vibration analysis

Here’s an annual-maintenance framework:
[Comprehensive HVAC Annual Inspection Checklist]

This is the difference between 10-year failure and 20-year lifespan.

Signs Your Daikin 10 Ton Unit Needs Immediate Attention

Don’t wait for the building to cook.
If you hear, smell, or see any of these, call for service:

Loud rattling
Burning smell
Weak airflow
Ice on lines
Water leaking
Breaker tripping
High humidity
Warm supply air
Excessive vibration
Frequent cycling
Abnormal energy spikes

RTUs send warning signs.
Ignoring them is expensive.

Tony’s Final Verdict

If you own a Daikin 10 Ton 15 IEER2 rooftop unit, you’re starting with a solid piece of equipment.
But even the best system can’t survive neglect, bad installation, or airflow problems.

A proper maintenance plan:

✔ Lowers energy bills
✔ Improves comfort
✔ Extends lifespan
✔ Reduces breakdowns
✔ Maintains warranty validity
✔ Lowers operating noise
✔ Improves air quality
✔ Prevents major repairs

Neglect maintenance?

You’ll pay for it three times over: