Free checklist
Makeup air unit (MAU) annual maintenance checklist
The annual makeup air unit service is the deep pass: the measurements, cleanings and tests a quarterly round doesn't reach. This checklist keeps the full service on record with the photos that make it defensible later. Work is commonly verified against IMC, manufacturer's published instructions. Confirm the edition your authority having jurisdiction has adopted.
The checklist
Every item, and the photo evidence it needs
The photo count on each row is what RTI would require before the item can be submitted. Work the list here and watch the gate hold, or load it into RTI and let it enforce the real thing.
Heat section
Burner and heat exchanger inspected and combustion checked
Direct-fired burner ports clean with an even flame, or indirect heat exchanger free of cracks and soot, gas pressure set per the rating plate.
No photoDischarge air temperature verified across the burner range
Tempered supply temperature measured and compared against setpoint as the burner modulates, no cold spots or overshoot.
No photoFlame supervision proven on gas-fired units
Flame signal read against the burner manual's range; manual valve shut mid-cycle and reopened only once the control has locked out and the main valve is confirmed shut, then reset per that manual.
No photoBurner and freeze safeties tripped and each shown to act
High limit, airflow proving, gas pressure and discharge low-limit switches tripped by the manufacturer's method, each shown to stop the burner or the unit, then reset.
No photoSupply air sampled for combustion products on direct-fired units
Analyzer reading taken downstream of the burner and compared with the manufacturer's limit and last year's value, profile plates adjusted if it has climbed.
No photo
Airflow and balance
Supply airflow measured against exhaust demand
Delivered airflow read against the total hood exhaust so the kitchen is held slightly negative to adjacent spaces without being starved of makeup air.
Building pressure checked at a door with the hoods running
Space pressure confirmed with all exhaust on; doors swing and latch normally, no whistling gaps or backdrafting appliances.
Lockout and electrical
Kitchen told cooking stops while the MAU is locked out
Kitchen manager and owner told before the lock goes on that an interlocked hood can't run while the MAU is down, so cooking stops until the unit is back.
No photoEvery MAU feed locked and tagged after the running tests
Gas shut and tagged on gas units, a start tried; the bearing run under load uses the procedure's temporary release (doors shut, clear, locks off by their owner), then re-locked.
Starter contacts, overload and terminals checked under lockout
Contactor faces free of pitting, overload set to the motor nameplate, terminal torque verified or resistance measured and re-torqued only where found loose, no heat discoloration.
Interlock relay or current switch located and its wiring traced
Device that starts the unit with the exhaust fan found with its enclosure dead, labeled and matched to the controls drawing, so the interlock path is on record.
Mechanical
Fan bearings inspected for play and noise
Bearings checked for shaft play and run listened to under load, greased per the schedule, set screws tight.
Blower wheel and cabinet interior cleaned
Wheel cleaned of grease buildup that throws it out of balance, drain pan and cabinet interior left clear.
Guards refastened and locks removed by the tech who hung them
Belt guard and access doors secured, gas valve reopened on gas units, each lock and tag taken off by its owner, and the unit restarted for the controls check.
Controls
Full start-to-stop control sequence exercised
Interlock, damper end-switch proving, burner enable and fan operation walked through in sequence, each step confirmed at the controller.
What usually sends this back
The failures are almost always the evidence, not the work
- Direct-fired burner sooting or running a lazy flame from drifted gas pressure, tempering the air unevenly and carrying combustion products into the supply stream.
- Supply airflow never measured against what the hoods exhaust, so the building stays slightly negative and back doors won't latch.
- Fan bearings run to failure because they were greased on the quarterly but never listened to or checked for play on a deep pass.
Verified against
Common questions
6 answers
- What does this makeup air unit (mau) annual checklist cover?
- 15 items across 5 sections, covering heat section, airflow and balance, lockout and electrical, mechanical, and more. Each item spells out what the person walking the job is actually looking for, not just a box to tick.
- Who should run this inspection?
- The HVAC service lead, ideally with the kitchen exhaust balanced on the same visit.
- When in the schedule should this walk happen?
- Once a year, before the heating season, so the burner is proven and the tempered-air delivery is set before cold outdoor air reaches the kitchen.
- Why do these items ask for a photo?
- 9 of the 15 items call for photo evidence, 11 photos in all. A checklist answer without the photo is a claim; the photo is what makes the record worth something in a dispute and lets a reviewer approve work without re-walking the job.
- What most often fails a makeup air unit (mau) annual inspection?
- Direct-fired burner sooting or running a lazy flame from drifted gas pressure, tempering the air unevenly and carrying combustion products into the supply stream. Supply airflow never measured against what the hoods exhaust, so the building stays slightly negative and back doors won't latch. Fan bearings run to failure because they were greased on the quarterly but never listened to or checked for play on a deep pass.
- Can I use this checklist in RTI?
- Yes. Start a free RTI workspace, build this list as a checklist, and the Photo Gate holds the submit button until every mandatory item is answered and its photos are attached. Approved inspections roll into a branded turnover package with a tamper evident audit trail.
Run it with the Photo Gate
A checklist nobody can submit half-finished
Load this list into RTI, stick a QR tag on the area it covers, and the submit button stays locked until every mandatory item is answered and the 11 required photos exist. Approved walks roll into a branded turnover package with a tamper evident record behind every line.
See all 508 checklists · 6741 items and 5984 photo requirements in total.