AERCO Esteem O&M Manual - Manual (Page 78)

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Boiler Control Module Display Messages
Boiler Control Module Display Messages
Display shows a number of 1 to 8 for the first digit on the left followed by 2 or 3 dig-
its (boiler temperature)
The boiler is in normal operating mode.
Display is blank
• Check for 120 volts at terminals L and N of the 120V terminal strip
• If no power is measured check the external power supply, external fuse or breaker.
• Check the internal fuse F1 by locating the control module and removing the black housing. The
internal fuse F1 is located in the right corner of the control module near the 120V high volt-
age electrical connector on the control as shown in Figure 27 on page 71. See “Control Module
Fuses” on page 70, for accessing the internal fuses of the control module.
• Disconnect electrical supply power to the boiler and remove the F1 fuse from the MCBA. Check
continuity across the fuse. If continuity is not present, the fuse has blown, replace the fuse with
a 5 amp/250V fast acting fuse. Check the wiring for possible causes for the fuse to blow.(short-
ed wiring to circulator)
• Check external wiring at 120V terminal strip and boiler internal wiring, ensure all wiring is prop-
erly connected, in good condition and all control module and boiler connections are secure.
• Correct/replace any mis-wiring or wiring components if needed. If problem continues replace the
control module.
Display shows UI.25 or UI.22
• Check transformer connections
• Check the internal fuse F3 by locating the control module and removing the black housing. The
internal fuse F3 is located in the center of the control module as shown in Figure 27 on page 71.
See “Control Module Fuses” on page 70, for accessing the internal fuses of the control module.
• Disconnect electrical supply power to the boiler and remove the F3 fuse from the MCBA.
• Check continuity across the fuse. If continuity is not present, the fuse has blown.
• • If fuse F3 has blown, replace the fuse with a 4-amp/250V slow acting fuse. Check external
boiler wiring for external source of 24V feedback.
Display shows a 0 for the first digit on the left followed by 2 or 3 digits (boiler tem-
perature)
• Check to see if room and DHW thermostats are satisfi ed.
• If the thermostats are satisfi ed the boiler is off due to no call for heat. Turn up a thermostat and
the boiler should begin ignition sequence.
• If the room thermostat or DHW thermostat is calling for heat and the boiler is not fi ring and the
boiler is below the maximum operating temperature.
• Check and verify Parameters 2 and 3 are correct as outlined on page 6. Both parameters
should be set as “01”, which turns DHW and CH modes ON.
Temporarily jump low voltage terminals 7 and 8 on the 24V terminal strip. If boiler operates check
the room thermostat wiring and thermostat control. Replace as needed. Remove jumper when
completed.
• Temporarily jump low voltage terminals 11 and 12 on the 24V terminal strip. If boiler operates
GF-125