Triangle Tube Boiler Error Codes: E02, E04 and E14

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

Triangle Tube Boiler Error Codes: E02, E04 and E14

Short answer

Match the Prestige control first. Triangle Tube's older MCBA uses E02 for failed ignition and E04 for power lost after a lockout. Its TriMax and CTRLMax controls use E1 for failed ignition and E2 for false flame. Check the recall information below before trying a restart.

Triangle Tube boiler error codes can be confusing because the same number means different things on different Prestige controls. In Triangle Tube’s manuals, older E02 means failed ignition, while E2 on TriMax and CTRLMax means flame detected before ignition.

Start with the control on your boiler, then use its section below. This guide covers Prestige Solo and Excellence with the older MCBA, TriMax and CTRLMax controls in the named manuals. Instinct, Challenger and other Triangle Tube ranges need their own charts.

Before you start

What to carry: a torch, your phone and the boiler’s paperwork. Keep the cabinet closed. Photograph the whole display and any model and serial label you can see without removing a panel. Include whether the fault followed a power cut, a heating call or hot water use.

Gas or electric? Triangle Tube’s Prestige manuals here cover gas fired condensing water boilers. These are not electric boiler or oil burner codes.

Renting? Send the display and model details to whoever arranges your heating repairs.

A code does not overrule these warnings.
Overheating or gas that will not shut off. Triangle Tube’s Prestige user manuals say to leave the pump’s electrical supply on and shut off the gas at a valve outside the boiler. Do not try a power reset in that situation.

Smell gas? Triangle Tube says not to light an appliance, touch an electrical switch or use a phone in the building. Leave and immediately call the gas supplier from outside, follow its instructions, and call the fire department if you cannot reach it.

A carbon monoxide alarm. CPSC says to get outside to fresh air, call 911 or the fire department, and check that everyone is accounted for. Stay out until emergency responders allow you back. If the boiler caused the alarm, do not use it until trained personnel have properly serviced it. Do not stay beside the boiler to investigate its code.

Flooding. Triangle Tube says not to use a Prestige if any part has been under water. It says to call a qualified service technician immediately to inspect the boiler and replace any control system parts and gas controls that were under water.

Inside the cabinet. Triangle Tube reserves its troubleshooting procedures for qualified service personnel. Leave gas valve adjustments, ignition tests and wiring repairs to a heating technician. Never bridge a safety control to get heat back.

Check the Prestige recall before a restart

Triangle Tube’s 2025 recall covers certain Prestige Solo, Prestige Excellence and Aerco Esteem boilers made from December 2011 through April 2019. Its identification notice lists serial prefixes AE, PT, PA, PTE and PEA; use the full model and serial ranges in the CPSC recall notice to confirm coverage.

CPSC says delayed ignition or component damage can release carbon monoxide. Its March 3, 2026 update says Triangle Tube is no longer in business and the remedy is unavailable to consumers who had not already registered. Do not rely on older instructions promising a new free repair booking.

If your boiler matches and you cannot confirm the repair was completed, arrange a safety assessment with a qualified boiler technician before attempting a restart. Have any previous recall paperwork ready.

Match the control, not just the Prestige name

Triangle Tube uses different code lists for these controls. The display examples are simplified; match the control in your boiler's paperwork.

Check 1No parts needed to identify the control

Choose the right code family

Older MCBA: Triangle Tube’s 2010 Prestige manuals show a small character display, with an E followed by the fault number. The Solo and Excellence charts both list E02 as failed ignition and E04 as power lost after a lockout.

TriMax or CTRLMax: Triangle Tube’s user manuals show a screen with a fault heading, explanatory sentences and an E code in the lower right corner. Keep the heading as well as the number. Their failed ignition code is E1.

The shared Solo or Excellence name does not identify the control generation. For example, Triangle Tube’s older Excellence manual uses the MCBA chart, while its Excellence TriMax manual uses the newer named faults.

Older Prestige MCBA: E02, E04 and E14

Check 2A service visit to test ignition and fuel supply

E02: ignition was not proved

Triangle Tube’s MCBA troubleshooting guide defines E02 as failure to establish flame detection during ignition, with lockout after five tries. It separates no spark, a spark without flame, and a flame that lights but is not maintained.

Its technician checks include the ignition electrode and cable, gas pressure during ignition, grounding and flame detection. Tell the repairer whether you heard attempts to start or noticed a brief run before the stop. Leave the burner enclosed while you do that.

It is not a diagnosis of one failed part. Triangle Tube’s different branches require different tests before replacement. Buying an igniter just because the screen says E02 skips that investigation.

Check 3A service visit; parts depend on the findings

E04: power was lost after a lockout

Triangle Tube’s MCBA guide says E04 appears when the boiler loses power after a lockout, and the original lockout code is lost. Turning the boiler off and on to clear that earlier fault can produce E04 too.

That explains why the number may change after someone tries the switch. Share any earlier photograph with the technician. Triangle Tube also lists supply interruptions, grounding or polarity problems, and an ignition cable short in its E04 investigation.

For these MCBA controls, Triangle Tube requires the fault to be corrected before pressing the display’s RESET button. Leave a recurring lockout for the repair visit rather than cycling the power again.

Triangle Tube's MCBA E04 sequence: power is lost after a lockout, and the original code is lost.

Check 4A service visit; parts depend on the test results

E14: investigate the low voltage circuit

Triangle Tube’s 2008 MCBA service guide labels E14 Internal Failure, then explains that a short or voltage feeding back into the 24 volt circuit may cause it. Its PS boiler FAQ describes E14 as a disturbance on the low voltage side.

The service guide has the technician check outdoor sensor wiring, voltage coming back from heating or hot water controls, and moisture at the terminal strip. These are internal electrical tests, not instructions to unplug sensors yourself.

The older Excellence installation chart gives only a service referral for E14. Show the technician the MCBA troubleshooting guide; the TriMax code list does not apply to this control. Triangle Tube’s TriMax and CTRLMax user charts cited here do not list E14 or E4.

TriMax and CTRLMax: the named faults

The meanings below come from Triangle Tube’s TriMax 2011-58 user manual and CTRLMax 2019-08 user manual. They apply to the controls covered by those editions, including their Excellence versions.

Code and message	Meaning in those Triangle Tube manuals
E1, Failed Ignition	The burner did not light after five attempts
E2, False Flame	Flame is detected before ignition; leave the investigation and restart to the technician
E3, High Boiler Temperature	The boiler reached its temperature limit
E5, Blower Speed	The blower speed is wrong, or its speed signal is missing
E8 / E9	The flame circuit test / gas valve circuit test failed
E15, Sensor Drift	A supply or return sensor reading has drifted
E16 / E17	The supply / return sensor reading is not changing
E18, Sensor Failure	A supply or return sensor reading changed very rapidly
E30 / E31	The supply temperature sensor circuit is shorted / open
E43 / E44	The return temperature sensor circuit is shorted / open
E34, Low Voltage	The incoming line voltage is below the operating range
E76 / E87, External Limit Open	An automatic reset / manual reset external boiler limit has opened

E13 means the reset limit was reached. Triangle Tube limits both controls to five resets in 15 minutes. That is a restriction, not a suggested number of attempts. Stop using resets to keep an unresolved fault running.

E37 is Low Water, but the pressure threshold differs. Triangle Tube’s TriMax user manual gives a shutdown below 10 psi; its CTRLMax manual gives below 7.2 psi. Neither number is a target to fill to. Both manuals specify 12 psi before startup.

Triangle Tube’s older Prestige user manual warns against adding cold water to a hot boiler because thermal shock can damage the heat exchanger. Record the gauge reading and any visible leak for the repairer; boiler pressure problems explains the wider investigation.

Extra CTRLMax entries: Triangle Tube’s 2019-08 chart adds E19 for flame lost after startup and E47 for a disconnected or broken water pressure sensor. It also lists E83 when the gap between supply and return temperatures is too large five times, and E84 when the flue temperature exceeds its limit five times.

What you can check outside the boiler

Check 5No parts for an accessible obstruction; service for damaged piping

Look at the air opening and visible piping

Triangle Tube’s Prestige user manuals allow an owner to remove a combustion air blockage only if it is easily accessible and removable. Look from a safe place on the ground. Leave fixed pipe joints connected and keep tools out of the boiler.

For a hidden or stubborn blockage, Triangle Tube calls for qualified service. Triangle Tube says to contact a qualified service technician immediately if you find vent blockage, leakage or deterioration. Give them the code too, and do not try to seal the vent yourself.

On TriMax and CTRLMax, Triangle Tube explains the reset method in the fault screen’s third sentence. The manuals separate automatic from manual resets, so there is no single button sequence for every fault. The safety and recall checks above come first.

Once the cause has been corrected, watch whether heat returns to the rooms and whether a fault reappears. If it runs and stops without warming the house, continue with a boiler that keeps turning off.

What each one takes

Finding	Work involved
Wrong chart for the control	Matching the model, control and full message before ordering anything
MCBA E02	Ignition, fuel supply and flame detection tests
MCBA E04	Recovering what happened before power was lost, then electrical checks
MCBA E14	Testing the low voltage circuit and connected controls
E37 on TriMax or CTRLMax	Checking water pressure and the cause of the low water condition
Visible vent damage	A heating technician repairing and checking the vent system

Questions people ask

Why does an older Prestige flash 9 and then b?

Triangle Tube’s MCBA manual describes that as a soft lockout: the display alternates between 9 with the water temperature and b with a two digit fault code. Its service guide says a soft lockout clears automatically once the condition is corrected.

What does E99 mean on a TriMax or CTRLMax?

Triangle Tube calls it Controller Bus Error: communication between the display and the boiler control has been lost. It is a different message from E98, which concerns communication with other boilers.

Why does my TriMax say Standby with no heat?

Triangle Tube defines Standby as no central heating or domestic hot water call received. Start with the heat request in boiler not working; that status alone is not an ignition error.

Can the technician see older TriMax faults?

Yes. Triangle Tube’s TriMax user manual says Lockout History retains the last eight lockouts and how long ago they occurred. Its details view includes the boiler information recorded when each fault happened.

Will an older MCBA Prestige protect itself from freezing while locked out?

Triangle Tube’s Solo and Excellence manuals say boiler freeze protection is disabled during a hard lockout, although the heating circulator operates. Arrange protection for the property if heat cannot be restored in freezing weather; do not assume that a running pump means the boiler is heating.

The other boiler guides: boiler not working, boiler pressure, and boiler keeps turning off.

Sources: Triangle Tube Prestige service troubleshooting guide 2008-36, revision 11/10/08, pp. 1, 8, 11, 16 to 18; Prestige Solo installation manual 2010-7, p. 49; Prestige Excellence installation manual 2010-28, p. 46; Prestige user manual 2010-46, pp. 1, 8; Prestige TriMax user manual 2011-58, revision 1/7/14, pp. 1, 6, 12, 17 to 20; Prestige Excellence TriMax installation manual 2011-61, pp. 51 to 52; Prestige Solo and Excellence CTRLMax user manual 2019-08, revision D August 2020, pp. 2, 4, 8, 21 to 23; Prestige Excellence CTRLMax installation manual 2019-07, pp. 49 to 50; Triangle Tube PS boiler FAQ and Product Recall 2025 page; CPSC recall 25-157, updated March 3, 2026, and Carbon Monoxide Questions and Answers.