Out of sight, out of mind — that's the rooftop unit's biggest problem. A clogged filter, a cracked belt or a stuck economizer can run for months before anyone climbs the ladder. OXMAINT AI is the AI-powered HVAC maintenance software that puts every rooftop unit on a schedule, so the roof gets visited before the tenants start calling.
Commercial HVAC · Rooftop Units · PM Checklist
Rooftop HVAC Unit Maintenance Checklist: Complete PM Guide
Rooftop units take sun, rain, wind and debris every day — and they quietly lose efficiency long before they fail. OXMAINT AI turns this checklist into scheduled work orders for every unit on every roof, logs what each technician finds, and turns every problem into a ranked repair.
Inside a Rooftop Unit — 6 Zones to Check
1Filters & Return Air
2Economizer & Dampers
3Blower, Belts & Motor
4Coils & Condensate
5Compressor & Refrigerant
6Heat Section & Controls
What Field Studies Found Inside Real Rooftop Units
Packaged rooftop units cool roughly 45% of U.S. commercial floor space. When researchers opened them up, most weren't running the way they were designed to — and almost every fault was something routine maintenance would catch. Start free and catch these faults on schedule in OXMAINT AI.
64%
Economizer failuresStuck dampers, failed sensors or bad settings — free cooling lost
46%
Failed refrigerant charge screeningToo much or too little refrigerant cuts capacity
~70%
Low airflowAt or below 350 cfm per ton, against the 400 cfm design norm
California field study of packaged rooftop units, reported to ACEEE (2004). Results vary by building and age.
The Rooftop Unit PM Checklist, Zone by Zone
Work through the unit in the same order every visit — from the air coming in to the controls at the end. The tag on each line shows how often it's typically due. In OXMAINT AI, the same checklist runs on a phone, and any line that fails becomes a work order. Book a demo to run this checklist on a phone in OXMAINT AI.
MMonthlyQQuarterlySSeasonalAAnnual
Typical intervals. Dusty sites, cottonwood season and kitchens need more frequent filter and coil work. Follow the manufacturer's manual.
Twenty Units, Five Roofs, One Schedule.
OXMAINT AI knows which unit is on which roof, what's due on each one, and who checked it last — so no rooftop unit is forgotten until it fails.
The Two Seasonal Switchovers
Twice a year, every rooftop unit changes jobs. These two visits catch more problems than any other — and OXMAINT AI schedules them for the whole fleet before the weather turns. Start free and schedule your seasonal visits in OXMAINT AI.
Spring · Cooling Start-Up
Clean condenser coils before the first heat
Check refrigerant pressures and charge
Clear condensate lines and traps
Test the economizer for the cooling season
Check compressor and fan motor amps
⇄
Fall · Heating Changeover
Inspect the heat exchanger for cracks
Clean burners, igniter and flame sensor
Test gas valve and safety controls
Check flue and venting for blockages
Confirm the heat stages come on in order
Trace the Symptom Back to the Check
When a tenant calls, the complaint usually points to a specific zone of the unit. Start there. OXMAINT AI logs each complaint against the unit, so repeat problems show up fast. Book a demo to see unit history in OXMAINT AI.
"It's too warm"
→
Dirty condenser coil, low charge or a stuck economizer
Zones 2, 4, 5
"Barely any air"
→
Loaded filter, slipping belt or a weak blower
Zones 1, 3
"Water on the ceiling"
→
Blocked condensate line or a dry trap
Zone 4
"Squealing on the roof"
→
Worn belt or failing bearings
Zone 3
"No heat this morning"
→
Dirty flame sensor, igniter or a tripped safety
Zone 6
Before Anyone Opens a Panel
Rooftop work combines electrical, gas and fall hazards. OXMAINT AI puts these steps at the top of every RTU work order, so they happen before the first screw comes out. Start free and build safety steps into your RTU PMs.
Fall ProtectionStay back from roof edges or use guardrails and tie-offs
Lock Out PowerOpen the disconnect and lock it before reaching inside
Shut Off GasClose the gas valve before working on the heat section
Verify DeadTest for voltage — capacitors can hold a charge
How OXMAINT AI Runs Your Rooftop Unit Program
The OXMAINT AI HVAC maintenance software gives every rooftop unit its own record, schedule and history, across every roof you manage. Book a demo to walk your RTU program end to end.
01
Unit RegisterEvery RTU with location, size, refrigerant and filter details.
02
Auto-Scheduled PMsMonthly, quarterly and seasonal visits built for each unit.
03
Mobile Roof ChecklistsZone-by-zone checks with readings and photos.
04
Findings to Work OrdersA failed check becomes a ranked repair instantly.
05
Parts on HandFilters and belts sized per unit, so the right ones go up.
06
Unit HistoryEvery visit, reading and repair to spot repeat problems.
Frequently Asked Questions
How often should rooftop HVAC units be serviced?
What is the most often missed part of RTU maintenance?
The economizer. Field studies found most economizers in rooftop units weren't working correctly, which wastes free cooling and can let in too much or too little outdoor air.
How often should rooftop unit coils be cleaned?
At least once a year, ideally before the cooling season. Units near kitchens, trees or dusty sites often need it more often.
Why does a rooftop unit leak water into the building?
Usually a blocked condensate line, a dry or missing trap, or a cracked pan. Checking the condensate system quarterly prevents most of these leaks.
How does OXMAINT AI help with rooftop unit maintenance?
The software registers every unit, schedules each PM automatically, runs checklists on a phone, turns findings into work orders and keeps a full history for each unit.
Every Rooftop Unit Checked. Before It Fails.
Put every RTU on every roof on one schedule with OXMAINT AI — zone-by-zone checklists, seasonal switchovers and a full history for every unit.
