Daikin MPS015 F Installation And Maintenance Manual page 37

Ignition Control Module LED Diagnostics
The LED indicators (Table 21) can be used to diagnose faults associated with the modulating gas furnace.
Table 21: Modulating Ignition Control Troubleshooting Guide (UTEC 1171 Ignition Board)
LED Indicator System Status
Heartbeat System Normal
Inducer ON
2 Flashes
No gas
3 Flashes No Flame
4 Flashes Lockout
5 Flashes Lockout
6 Flashes No Flame
7 Flashes No Flame
8 Flashes Lockout
9 Flashes Lockout
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Fault Description
N/A
Combustion air flow pressure switch
contact is open; combustion inducer fan
is running
Combustion air pressure switch contact
is closed when fan is not running.
Failed to ignite after too many failed
attempts
Burners light and then drop out resulting
in too many flame failures
Inducer fan is running on high speed,
burners are OFF, high limit is open.
Rollout switch has tripped open
Flame is present without any call for
heat
Exceeded max limit trips in one call for
heat
Possible Causes and Corrective Action
All conditions are normal
Pressure switch open with inducer ON
1. Combustion air flow pressure switch hose leaking; repair and/or replace
2. Combustion air flow pressure switch hose plugged; repair and/or replace
3. Combustion air flow pressure switch hose fittings plugged or damaged; repair
and/or replace
4 Combustion air pressure hose and/or switch has condensate accumulation;
repair and/or replace
5. Combustion air pressure switch not functioning; replace
6. Combustion inducer fan not working; repair or replace
Pressure switch close with inducer ON
1. Check wiring to the combustion air flow pressure switch.
2. Check combustion air flow pressure switch continuity with OHM meter; if not
open replace
Lockout from too many failed ignition tries
1. Confirm gas supply available; verify manifold gas pressure is correct.
2. Verify manual gas shut-off valve is open.
3. Verify Gas Safety Control valve is in On position.
4. Confirm that spark is present. If not, check spark igniter for debris between
electrodes, cracked ceramic and damaged or disconnected wire connection.
Check ignition wire for cracks, coated with oil and debris.
5. Check for air leaks at inducer fan assembly and flue
6. Check for recirculation of exhaust flue gases.
7. If all above condition are OK, replace ignition board
Lockout from too many flame losses
1. Check flame sensor ceramic is not cracked; check flame rod for being coated
with debris and oil.
2. Check flame sensor wire is connected correctly; not cracked, no abrasions and
not covered with debris.
3. Check for recirculation of exhaust gases.
4. Check flame stability and proper location from sensor.
5. Check that pressure switch is not dripping due to loss of pressure.
High temperature switch open
1. Check temperature rise and air flow over furnace heat exchanger
2. If high limit does not reset, change high limit switch
Rollout switch open
1. Check for blockages in exhaust vent assembly
2. Check for air leaks inside the burner compartment
3. Reset the Rollout switch and observe flame for any signs of rollout.
Flame present with gas OFF
1. Verify there is no voltage to the gas valve
2. Check gas line pressure making sure it is not higher than allowed by gas valve
manufacturer
3. If valve is not energized, check for gas flow. If gas is flowing, replace gas valve;
verify line and manifold gas pressure are correct.
Exceeded maximum limit trips in on call for heat (5)
37 IM 1058-8 • MAVERICK II ROOFTOP SYSTEMS
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