MPO-IQ Installation, Operating, and Service Instructions
65
XIII. TROUBLE SHOOTING (continued)
E. USE BOILER CONTROL DISPLAY ERR AND ERP NUMBERS TO DIRECT TROUBLESHOOTING (continued)
Display Status Recommended Corrective Actions
ErP 23
Flame Out of Sequence,
During Pre-Purge
Flame was proven during the valve on delay period. Check the oil valve for proper
operation.
If the system does not have an oil valve, set the valve on delay to 0.
ErP 24
Flame Out of Sequence,
During Post-Purge
Flame remained lit during the burner off delay. Check the oil valve for proper operation.
If the system does not have an oil valve, set the burner off delay to 0.
ErP 25
Manual Reset Required
Check Oil Primary and Option Panel Displays:
- If Option Panel display shows “OL- “, Open Limit: the display will indicate the card that has
a manual reset lockout. Follow instructions included with card to reset the lockout.
- If The Oil Primary is locked out refer to ERP 20 for additional information.
ErP 34
CAD Ohms Permanently
Low (ame out of
sequence)
The cad cell is permanently in a low resistance state. It should typically read much higher
than 20,000 ohms when no ame is present.
- Set the display to display cad cell resistance.
- Shield the cad cell from light
If the display shows less than 20,000 ohms, unplug the cad cell,
If display does not read 999999 ohms, replace control,
If it does read 999999 ohms, replace cad cell.
ErP 53
Outdoor Air Reset
Option Card,
Sensor Failure
Temperature sensor or interface failure (open or short connection or increased connection
resistance) or control hardware failure.
ErP 58 AC Line Frequency Error Check power supply.
ErP 59 AC Line Voltage Error
Supply voltage is low to the control.
Measure the voltage across screw terminals "2" and "3"
If it's greater than 22VAC and the error does not clear, replace control.
If it's less than 22VAC, review appliance wiring.
ErP 84
LWCO Option Card,
Low Water Event
Low water level Limit has caused the boiler to shutdown. Make sure that the water level has
reached the probe. Limit will re-close automatically after water level is restored.
ErP 89
Outdoor Air
Reset Option Card,
Communications Error
Loose wire between the Option Panel and Boiler Control or control failure.
ErP 91 Communication Error
Communications error has been detected.
Remove all devices from the Enviracom connections, 3-pin plug and screw terminals "1-2-3".
If the error does not clear within one minute, measure the voltage on terminals "2" and "3".
If the voltage across terminals "2" and "3" is between 20VAC and 30VAC, replace control.
If it is outside of that range, review boiler wiring. There should be approximately 24VAC
across "2" and "3".
ErP 119
Aquastat
Option Card,
Sensor Failure
Temperature sensor or interface failure (open or short connection or increased connection
resistance, dual sensor mismatch) or control hardware failure.
ErP 140
LWCO Option Card,
Low Probe Signal
Warning, level monitoring signal is low. The probe may be dirty. Fluxes or oils used during
the construction of the boiler or installation of system piping can coat the probe, preventing
signals from being received by the LWCO Option Card. Add a cleaning solution, (such as
water and tri-sodium phosphate or consult the boiler manufacturer), to the system. Heat
and circulate this solution for at least one hour before draining and completely ushing the
system with clean water. Remove the probe and thoroughly wipe it with a clean rag. Rell
the system and test for proper operation.
ErP 141
LWCO Option Card,
Manual Reset Lockout
A manual reset, low water limit has caused the boiler to shutdown. Make sure that the
water level has reached the probe. Limit will NOT re-close automatically after water level is
restored. To reset the control follow the LWCO Option Card Reset Pushbutton procedure.
TABLE 15B: EXTERNAL DEVICE (Oil Primary, Option Card, etc.) ERROR NUMBER (continued)