What does this tankless water heater annual checklist cover?

14 items across 5 sections, covering isolation and lockout, descale and flush, burner service, heat input and relief, 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 plumbing service tech on the annual service visit.

When in the schedule should this walk happen?

Once a year, and sooner where the water is hard, since scale in the exchanger is what steals temperature and eventually cracks the unit.

Why do these items ask for a photo?

7 of the 14 items call for photo evidence, 8 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 tankless water heater annual inspection?

A quick flush run without descaling solution, so scale that's already coating the exchanger passages stays put and output keeps drifting down. Burner and flame sensor left untouched, so a unit that's slowly fouling keeps clearing ignition faults until it finally locks out in cold weather.

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.

Free checklist

Tankless water heater annual maintenance checklist

The annual tankless water heater 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 IPC / UPC plumbing codes, manufacturer's published instructions. Confirm the edition your authority having jurisdiction has adopted.

Start free with this checklist Download as PDF

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.

Isolation and lockout

Occupants told hot water is off and test draws will run hot
People served by the heater told before isolation that hot water is off for the service and that the checks afterward can run hot at the fixtures.
No photo
Unit locked out and tagged before the pump kit goes on
Every circuit and, on gas units, the gas valve locked and tagged by each worker. For run checks: refilled, air purged, locks off by whoever hung them, run, then re-locked before hands go back in.
Service valve kit and purge ports checked where fitted
Where a service valve kit is fitted, cold and hot isolation valves close and hold, purge port caps come off cleanly, and a valve that passes water is reported before the hoses go on.
No photo

Descale and flush

Descaling agent label checked against the manufacturer
Product label matches the manual's allowed descaler type and dilution, and spent solution is disposed of as its label and the site's rules require.
Heat exchanger descaled and flushed
Isolation valves used to circulate descaling solution through the exchanger, then flushed clean, scale volume in the return noted to set the next interval.
Inlet screen and flow verified after flush
Inlet screen cleaned again after descaling, flow rate and delivered temperature re-checked to confirm the descale actually restored output.

Burner service

Burner, flame sensor and igniter cleaned and serviced
Burner assembly and flame rod cleaned per manufacturer schedule, igniter checked, flame pattern and ignition re-verified after service.
No photo
Combustion and venting proven after service
Combustion confirmed within the manufacturer's range after cleaning, vent and condensate path re-checked end to end, no fault codes on restart.
No photo
Neutralizer cartridge checked on condensing gas units
Where fitted, remaining media judged against the neutralizer maker's guidance and a pH strip read at its outlet; spent media renewed and the date marked on the housing.
No photo

Heat input and relief

Supply and element terminals torque-verified on electric units
On electric units, locked out, supply and element terminals checked for heat marks and torque-verified to the manufacturer's value, re-torqued only where found loose.
No photo
Heat input checked: gas pressures or element resistance
Gas units: inlet and manifold pressure read at the test ports at full fire against the rating plate. Electric units: each element's resistance read locked out against the manual.
Relief valve set pressure matched to the unit's rating
Set pressure stamped on the valve compared with the rating plate's maximum working pressure; discharge line unreduced, uncapped and ending where hot water cannot hit anyone.

Return to service

Unit back in service at its recorded setpoint
Locks removed by whoever hung them, valves open and purge port caps back on, and the display showing the recorded setpoint with no active fault after a hot draw.
Service record updated and deficiencies sent to the owner
Post-service flow and rise, heat input readings and any deficiency entered against the unit tag, and repairs needing approval written up for the owner.
No photo

What usually sends this back

The failures are almost always the evidence, not the work

A quick flush run without descaling solution, so scale that's already coating the exchanger passages stays put and output keeps drifting down.
Burner and flame sensor left untouched, so a unit that's slowly fouling keeps clearing ignition faults until it finally locks out in cold weather.

Verified against

IPC / UPC plumbing codes

Common questions

6 answers

What does this tankless water heater annual checklist cover?: 14 items across 5 sections, covering isolation and lockout, descale and flush, burner service, heat input and relief, 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 plumbing service tech on the annual service visit.
When in the schedule should this walk happen?: Once a year, and sooner where the water is hard, since scale in the exchanger is what steals temperature and eventually cracks the unit.
Why do these items ask for a photo?: 7 of the 14 items call for photo evidence, 8 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 tankless water heater annual inspection?: A quick flush run without descaling solution, so scale that's already coating the exchanger passages stays put and output keeps drifting down. Burner and flame sensor left untouched, so a unit that's slowly fouling keeps clearing ignition faults until it finally locks out in cold weather.
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.

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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 8 required photos exist. Approved walks roll into a branded turnover package with a tamper evident record behind every line.