Burnham Alpine Boiler Error Codes: What They Mean

By Ray Bennett · Updated 17 October 2026 · 9 min read · Checked against the sources at the end

Burnham Alpine Boiler Error Codes: What They Mean

Short answer

U.S. Boiler's Alpine Sage2.X chart calls 11 ignition failure, 17 a normal wait for blower speed, and 19 failed purge speed proving. These meanings cover ALP080B through ALP285B. ES2 uses a different control: Err 32, 56 and 63 belong to its own chart below.

Burnham Alpine boiler error codes can look worrying, but U.S. Boiler’s Sage2.X chart includes both normal waits and faults that need a repair. Code 17 is a wait for blower speed; code 19 means the control could not prove the required purge speed.

This guide covers Alpine ALP080B through ALP285B with the Sage2.X control. There is also a separate ES2 table for readers searching Burnham codes 32, 56 or 63. Keep the boiler model and the words on its display together before choosing a chart.

Before you start

What to carry: a torch, a pen and the manual supplied with your boiler. These checks do not need tools inside the cabinet.

Gas or electric? U.S. Boiler’s manuals here cover gas fired hot water boilers. They are not code lists for an oil burner, electric boiler or steam system.

Renting? Send the model and full fault message to whoever arranges the heating repairs before authorising work.

Handle danger before looking up the number.
Overheating, or gas that will not shut off. U.S. Boiler’s Alpine user manual says to leave the pump’s electrical supply on and shut off the gas at a valve outside the appliance. Do not try a power reset in that situation; arrange urgent service.

A smell of gas. The same manual says not to light an appliance, touch an electrical switch or use a phone inside. Leave and call the gas supplier from outside; call the fire department if the supplier cannot be reached.

A carbon monoxide alarm. CPSC says to move outside to fresh air, call 911 or the fire department, and stay out until emergency responders allow you back.

If you see soot in or near the burner compartment, U.S. Boiler says to shut the boiler down immediately and call a qualified gas service technician. Do not restart it until the cause has been found and corrected.

Repairs belong to a qualified gas service technician. U.S. Boiler says the Alpine has no user serviceable parts. Leave wiring, gas pressure, burner work and safety switches alone. If any part has been under water, its user manual says not to use the boiler until the required inspection and replacement work is done.

Find the whole message first

A model, a complete message and a lockout type give you something useful to work from. This is a simplified example, not the actual screen layout.

Check 1No parts to buy for this check

Match the boiler and its control

Use the model on your boiler paperwork or its accessible identification label. The Alpine tables below come from U.S. Boiler’s manual 103448-12, dated August 2024. They cover its B models, not every boiler carrying the Burnham name.

On these Alpines, U.S. Boiler says a lockout turns the display red and makes the Help button blink. Select Help to see the cause, then write down the number, wording and what happened before the heat stopped.

For the ES2, U.S. Boiler distinguishes Err, an error, from StA, an operating status. Its Intelligent Hydronic Control and lower IQ Option Panel also have separate displays. Keep that prefix and which display showed it in your record.

Alpine soft lockout codes

U.S. Boiler lists these under soft lockouts for the Alpine Sage2.X control. Its chart says the boiler restarts automatically once the condition is corrected; the ignition delay is explained below. The repair clues are for the technician, not instructions to open the boiler.

Alpine code	What U.S. Boiler means	What the investigation involves
1: Anti Short Cycle	The minimum time between starts has not elapsed	A normal delay to avoid excessive cycling
2: Boiler Safety Limit Open	An internal safety circuit is open	Condensate float, thermal link, burner door thermostat, air pressure switch, high limit or wiring
3: Boiler Safety Limit Open	The boiler or external limit circuit is open	The external safety device, low water cutoff and wiring
7 / 8 / 9 / 10: Sensor fault	Open or shorted return / supply / domestic hot water / flue temperature sensor, respectively	The named sensor and its wiring
11: Ignition failure	Flame failure after five tries to restart	Fuel supply, ignition components, grounding and combustion
13: Flame rod shorted to ground	A short in the flame sensing circuit	Flame rod and wiring
14: Inlet/outlet temperature difference high	Too much temperature rise between supply and return	Inadequate water flow, pump operation and piping size
15: Return temp higher than supply	The return sensor reads hotter than the supply for at least 75 seconds	Reversed flow, no flow, reversed sensor wiring or a faulty sensor
16: Supply temp has risen too quickly	Supply water heats too fast	Water flow, circulators and the high limit causes
17: Blower speed not proved	A normal wait for blower speed to match the purge or light off setting	Whether the startup sequence moves on

Check 2A service visit; parts depend on testing

Code 11: find why it could not light

For the Alpine B models, U.S. Boiler gives ignition failure a one hour soft lockout after the retry sequence. That explains a boiler sitting quiet after unsuccessful starts.

Its code 11 checks include absent or low gas pressure, air in the gas line, an electrode or ignition cable fault, a loose burner ground, the gas valve and an incorrect air and fuel mixture. The technician needs to find which condition is present before choosing a part.

Do not confuse it with code 12: U.S. Boiler defines that as flame detected when none should be present and includes a defective gas valve among its causes. Leave that restart to the repairer.

Alpine hard lockout codes

These are U.S. Boiler’s Sage2.X hard lockouts. Unlike an automatic restart, they require a manual reset after the cause has been corrected.

Alpine code	What U.S. Boiler means
4: Supply high limit	Supply sensor detected a temperature above 210 degrees F
5: DHW high limit	Domestic hot water sensor detected a temperature above its setpoint
6: Stack high limit	Flue gas sensor detected a temperature above 204 degrees F
12: Flame detected out of sequence	A flame signal when there should be no flame
18: Light off rate proving failed	Blower not at the required ignition speed, or its speed signal not detected
19: Purge rate proving failed	Blower not at the required purge speed, or its speed signal not detected
20 / 21: Invalid parameter	Unacceptable safety / modulation setting, respectively
22: Safety data verification needed	A safety setting changed without completing verification
23: 24VAC voltage low/high	The control’s 24 volt AC power is too high or low
24: Fuel Valve Error	Power detected at the fuel valve output when the valve should be off
25 / 26: Hardware / Internal Fault	Internal control failure
27: Unknown Fault	The chart gives no more specific condition

Check 3No repair for a normal wait; service for a failed start

Code 17 or 19: watch what follows

If 17 appears briefly and the boiler goes on to heat, U.S. Boiler’s chart describes that wait as normal. If it stays there and the house remains cold, report the stalled start with your fault record.

For codes 18 and 19, U.S. Boiler lists loose blower power wiring, a loose or incorrectly wired speed harness, and a defective blower. Hearing the fan run does not rule out the missing speed signal named in its chart.

U.S. Boiler separates waiting for speed from failing to prove it. Codes 18 and 19 can involve the blower, its wiring or its speed signal.

What you can check outside the Alpine

Check 4No parts for an outside inspection; service for a vent fault

Look at a wall vent you can reach from the ground

U.S. Boiler’s Alpine user manual tells owners whose boiler has stopped to inspect the outside vent terminal for a blockage, such as ice or a nest, if it is accessible from the ground. Stay on the ground and do not dismantle the vent.

If you cannot reach it, or see no blockage, the manual calls for a qualified gas service technician. It also says a pressure switch shutdown needs the venting problem diagnosed and corrected before that switch is reset.

For codes 14, 15 or 16, U.S. Boiler’s service chart points toward water flow and sensor checks instead. Tell the repairer whether any rooms still heat. The related guide to boiler circulator pump problems explains that side of the system.

Check 5Diagnosis first; the fault decides the parts and labor

Treat the reset as the end of the repair

For an Alpine Sage2.X hard lockout, U.S. Boiler identifies a Reset button on the Active Fault display or on the control itself. You do not need to remove a cover to hunt for a button.

After the repair and restart, check that the rooms warm and the fault stays cleared. If a shutdown could freeze pipes, U.S. Boiler says not to leave the heating unattended in cold weather without alarms or other safeguards. Arrange a way to check the house if you must leave.

Burnham ES2 codes 32, 56 and 63

U.S. Boiler’s ES2 manual uses an Intelligent Hydronic Control within the IQ Control System. This table is for that control’s Err display, not the Alpine or the ES2’s separate IQ Option Panel.

ES2 display	What U.S. Boiler means	What the technician checks
Err 32	Temperature Sensor Failure	Sensor connection, sensor/interface faults or control hardware
Err 55	Damper Failed to Open	The vent damper end switch did not close
Err 56	Damper Failed to Close	Damper, wiring harness and control output
Err 63	Soft lockout: maximum recycles exceeded	The manual’s ignition troubleshooting sequence, including pilot, spark, gas supply and flame sensing

For Err 56, U.S. Boiler’s tests distinguish a control output fault from a damper or harness fault. The code alone is not a reason to buy a new damper. Those tests involve electrical measurements and disconnected wiring, so leave them to the technician.

What each one takes

Finding	What the work involves
Alpine 1 or brief 17, then normal heating	Watching the normal delay finish
Alpine ignition, flame or fuel valve fault	A gas service technician testing the fuel and ignition system
Alpine water temperature or flow fault	Checking circulation, piping, sensors and controls
Alpine blower hard lockout	Testing power, speed feedback and the blower before replacing parts
ES2 sensor or damper fault	Electrical diagnosis, then the part identified by the tests

Questions people ask

Why does my Alpine fault disappear before I can read it?

U.S. Boiler describes a blocked vent opening the air pressure switch after the blower starts, then the switch closing again when the blower stops. On these Alpines, the display shows that cause only while the switch is open. The outside vent check above covers the owner’s part.

Is ES2 StA 15 the same as Alpine code 15?

No. U.S. Boiler calls ES2 StA 15 “Waiting for Limit to Close” and directs troubleshooting to the IQ Option Panel. Alpine Sage2.X code 15 concerns return temperature reading higher than supply temperature.

Can I fix an Alpine low water problem by topping it up?

U.S. Boiler’s Alpine user manual says to have the system checked for leaks if water needs adding. It warns that frequent additions can seriously damage the stainless steel heat exchanger. Arrange that check rather than making refilling a routine.

Does an Alpine without a code need servicing?

Yes. U.S. Boiler’s Alpine user manual calls for annual maintenance by a qualified gas service technician. A clear display does not replace that visit.

What if my number is not in these tables?

Match the full model and control to the manual supplied with the boiler. These charts cover the named Alpine B models and selected ES2 errors. Do not apply them to earlier Alpine controls, commercial C models, K2WT or another Burnham series.

The other boiler guides: boiler not working, boiler keeps turning off, boiler pressure, and Weil-McLain boiler error codes.

Sources: U.S. Boiler Company Alpine Installation, Operating and Service Instructions 103448-12 8/24, pp. 1, 4, 93, 97, 128 to 134; Alpine User's Information Manual 103449-01 2/13, pp. 1 to 3; ES2 Installation, Operating and Service Instructions 103780, July 2026, pp. 7, 16, 27, 30 to 31; CPSC Carbon Monoxide Questions and Answers.