53

C. Troubleshootingproblemswhereahardlockoutcodeisdisplayed.Whenahardlockoutoccurs,theboiler 

willshutdownandthedisplaywillashtheletter“E”followedbyatwodigitservicecode.Oncethecondition

thatcausedthelockoutiscorrected,theboilerwillneedtobemanuallyresetusingtheRESETbuttononthe 

display.

CODE CONDITION POSSIBLE CAUSES

E 00 A ame signal was present when there should
be no ame.
• Defective gas valve - make sure inlet pressure is below maximum
on rating plate before replacing valve.
E 02 Flame failure after 5 tries to restart
• No gas pressure
• Gas pressure under minimum value shown on rating plate
• Gas line not completely purged of air
• Defective Electrode
• Loose burner ground connection
• Defective Ignition Cable
• Loose or defective gas valve harness
• Defective gas valve (check for 24 VDC at harness during trial for
ignition before replacing valve)
• Air-fuel mixture out of adjustment - consult factory
E 03 Gas valve error
• Loose or defective gas valve harness. Check electrical
connections.
• Defective gas valve (check for 24 VDC at harness during trial for
ignition before replacing valve)
E 04 Power failure occurred after lockout • Some other error on this list occurred and power to the boiler was
then interrupted. Reset control and see if hard lockout reoccurs.
E 05
E 06
E 07
E 11
Internal control failure • Reset the control. If problem reoccurs, replace the MCBA.
E 12 Low water cut-off circuit open
• If yellow light on LWCO is on, system is low on water
• If neither yellow nor green light is on, check LWCO harness and
check for 24VAC across AT140 transformer
E 13
E 14
E 15
E 16
E 17
Internal control failure • Reset the control. If problem reoccurs, replace the MCBA.
E 18 MCBA supply sensor detected temperatures in
excess of 200°F for an extended period of time
• See possible causes for “b18” error. Also, check safety limit for
proper operation.
E 19 MCBA return sensor detected temperatures in
excess of 200°F for an extended period of time • See possible causes for “b19” error.
E 28 Blower is not running when it should or fan
speed signal not being detected by MCBA
• Loose connection in 120 VAC fan wiring
• Loose or miswired fan speed harness
• Defective fan
E 29 Blower fan speed has not returned to zero rpm • Miswired fan speed harness
• Defective fan
E 31 Shorted supply temperature sensor • Shorted or miswired supply sensor wiring
• Defective supply sensor
E 32 Shorted return temperature sensor • Shorted or miswired return sensor wiring
• Defective return sensor
E 35 Flue gas temperature sensor short circuit • Shorted or miswired ue temp sensor wiring
• Defective ue temp sensor
E 36 Supply water temperature sensor circuit open • Loose or miswired supply sensor wiring
• Defective supply sensor
E 37 Return water temperature sensor circuit open • Loose or miswired return sensor wiring
• Defective return sensor
E 40 Flue gas temperature sensor circuit open • Loose or miswired ue temp sensor wiring
• Defective ue temp sensor
E 44 Internal control failure • Reset the control. If problem reoccurs, replace the MCBA.
E 52 Flue gas temperature over 230°F
• Heat exchanger needs to be cleaned
• Boiler over-red
• Air-fuel mixture out of adjustment - consult factory
E 60 Internal control failure • Reset the control. If problem reoccurs, replace the MCBA.
Table 13.4: Hard Lockout Codes Displayed