Instruction manual
47
P/N HN-IOM-1 82-0331 Copyright 2009 Mestek, Inc.
Finned copper tube gas boilers & water heaters – Control manual
Line #4 log entriesTable 10
Troubleshooting (continued)
9
Line #4 entry Explanation
SETBACK#1 IS ACTIVE
SETBACK#2 IS ACTIVE
SETBACK#3 IS ACTIVE
SETBACK#4 IS ACTIVE
SETBACK#1 IS EXPIRED
SETBACK#2 IS EXPIRED
SETBACK#3 IS EXPIRED
SETBACK#4 IS EXPIRED
If one or more of the setbacks is enabled, these entries will occur when the setback is started or
ended.
NO LOCAL SYSTEM FLOW
NO SYSTEM FLOW
is indicates failure of ow proving (switches wired to J11A and J11B).
COMBUSTION AIR FAIL
Logs if the combustion air damper is used and does not prove across J10B DAMPER or J12B
DAMPER
SYSTEM RESET -- ---
Records the type of reset the control board experienced —
O: stack overow; U: stack underow; (both of these are soware faults)
R: reset instruction (rmware or default load)
W: Watchdog (rmware code ran erroneous code and rebooted)
P: Power-ON (Power switch toggled)
B: Brown-out (Microcontroller saw a voltagle less than 4.5 VDC)
OUTDOOR RESET
is message indicates that warm weather shutdown is in eect.
HIGH DELTA TEMP
is message occurs when the temperature across the heat exchanger is greater than 40 °F.
LOW RETURN TEMP
If the return temperature is less than 130 °F, condensation may occur.
SHUTDOWN UV TEST
Aer 24 hours of continuous operation, the ignition control module must check its UV detector. e boiler
will shutdown and restart, allowing the self-check to occur on start-up. is message indicates this sequence
has occurred.
HIGH LIMIT EXCEEDED
is indicates the limit control has exceeded it limit.
IGNITION CTRL ALARM
is indicates the ignition control module faulted while performing an ignition sequence or while monitor-
ing during ame operation.
IRI ALARM
is indicates the gas valve proving circuit detected a gas pressure problem.
DOMESTIC HOT WATER
is indicates the occurrence of a DHW call for heat from a DHW sensor or external DHW aquastat.
LOW WATER CUT-OFF
VAR FREQ DRIVE
GAS PRESSURE
SPARE 4
OP LIMIT MECH
ese are faults due to interlocks connected to 24VAC interlock inputs on J11A and J11B.
OP LIMIT REMOTE
is indicates the soware operating temperature limit was exceeded.