Daikin DPS010 - Table 24 continued: Functional Alerts

Table 24 continued: Functional Alerts
Display Information Alert Description Possible Cause Solution
AO4
Limited Low Fire
Automatic adaptive
program is currently
limiting the lower range
of modulation at avoid
ame loss at minimum re
conditions. The alert is
displayed during the run
cycle once a ame-out
condition has triggered the
Limited Low Fire function.
This function is reset by
cycling power to the board.
A. Low gas line pressure
1. Insure gas supply is
connected to furnace
and check for proper
line pressure.
B. Insufcient intermediate
gas manifold pressure
through gas safety
valve
1. Check for faulty gas
valve wiring.
2. Check 24 VAC to gas
valve assembly.
3. Check inlet pressure to
safety gas valve.
4. Check outlet pressure
from the safety gas
valve – adjust as
needed.
5. Replace safety gas
valve if faulty.
C. Faulty burner operation
1. Check for proper
mounting of the burner
assembly.
2. Check burner orice
for proper size and
blockage.
D. Faulty ame sensor
1. Check ame rod wiring
and connections.
2. Check for proper
alignment of ame rod.
3. Clean ame rod sensor.
E. Improper alignment of
the modulating actuator
and the gas ball valve
1. Check that the
alignment of the
actuator to the ball
valve is correct. The
ball valve must be in
the fully open position
when the actuator
is fully energized
(“ACTUATOR DRIVE”
= 9.6 VDC or greater).
2. Insure that the set
screw on the actuator
is tightened to the ball
valve stem.
F. Blocked or improper
venting
1. Check air inlet and
outlet for blockage.
2. Check venting
conguration for
excessive venting
length, improper sizing,
etc.
AO5
Weak Flame Signal
The ame signal level is
less than optimal for this
furnace. Maintenance
of the ame sensing
components is advised.
A. Flame sensor coated 1. Clean ame rod sensor.
B. Flame sensor
improperly mounted or
grounded
1. Check ame sensor
wiring integrity and
ceramic for cracks.
2. Re-install / replace
ame sensor.
C. Unstable ame pattern
1. Check that all burner
assembly components
are properly installed.
2. Check that all seals
between the vestibule
area and the heat
exchanger area are
tight.
3. Insure that the
combustion door
gasket is in place and
the door is properly
installed.
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