Reznor MAPS III, Cabinet D RECB Users Manual - Manual (Page 41)

Form O-MAPSIII Cabinet D, P/N 222918R9, Page 41
Gas Heat Section Modulating Control LOCKOUT ERRORS
Code Alert Description Probable Causes Solutions
Ignition Board
Failure (888)
Ignition board start-up checks
have detected an error.
A. Faulty transformer 1. Check 24-volt transformer for correct output.
2. Check connections and wiring to control board and other
components connected to the 24 volt source.
3. Replace if necessary.
B. Faulty control board 1. Turn off power to the furnace, wait 30 seconds and turn
power back on. Re-try ignition sequence and see if the
system responds.
2. Replace control board if necessary.
Failed Ignition
(EO1)
Maximum
Retries (3)
Exceeded
The flame could not be
established during multiple
trial-for-ignition periods (3).
The maximum number of
retries has been exceeded
and the furnace is in a lockout
condition. System Shutdown
alarm lockout will need to
be reset through BacView
interface or IQ controller will
need to be power cycled.
A. Insufficient gas line
pressure
1. Insure gas supply is connected to furnace and check for
proper line pressure.
B Gas valve control turned
“OFF”
1. Turn gas valve to the “ON” position
C. No spark from direct spark
ignition
1. Check ignition voltage (115 VAC from board to
transformer) and wiring.
2. Check 24 VAC transformer for DSI board.
D. Insufficient 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.
E. Insufficient gas manifold
pressure to burner through
modulating ball valve
assembly
1. Check voltage to gas valve actuator. (7 – 10 VDC
depending on model)
2. Check alignment and setscrew connection between ball
valve and actuator (See procedure in Paragraph 4.3.).
F. Burners do not light 1. Check spark rod assembly for proper location, spark gap,
etc.
2. Verify that the spacing between the burner body and the
burner shield is equal across the entire length of the burner.
3. Check burner orifice for proper size and blockage.
G. Burners light and remain
lit for about 5 seconds
1. Check flame rod wiring and connections.
2. Check for proper alignment of flame rod.
3. Clean flame rod sensor.
Primary Limit
/ Fuse Failure
(EO2)
The control board safety fuse
has blown or the primary
temperature limit has opened
indicating safe operating
temperatures for this furnace
have been exceeded.
A. Improper circulating
airflow
1. Check filter / replace if dirty.
2. Check for improperly sized duct system.
3. Check for faulty blower motor.
4. Check for faulty blower motor wiring.
B. Primary limit switch failure 1. Check for an open primary limit switch at ambient
temperature.
C. Fuse is blown 1. Check and replace fuse on the board.
2. Make sure fuse socket is tight, crimp fuse terminals if
necessary.
D. Faulty primary limit switch
wiring
1. Check primary limit wiring continuity from the switch to the
control board.
Modulation
Valve Failure
(EO3)
The control lost the position
feedback from the modulating
gas valve actuator.
A. Faulty modulation valve
actuator wiring
1. Ensure wiring is connected per unit wiring diagram.
2. Check for loose pins or bad connections.
3. Check for frayed wiring or shorts to ground.
B. Modulation valve actuator
failure
1. Ensure actuator has 24 V power.
2. Ensure actuator is receiving signal from the control board
(2-10 VDC).
3. Check for actuator feedback to the control board (2-10
VDC)
Air Sensor
Failure (EO4)
Pressure
Sensor
Reading Low
The air sensor reading is too
low for operating conditions or
the air pressure switch closed
when the sensor indicates
low flow
The pressure switch MUST be
open prior to venter activation.
A. Faulty wiring or
connections
1. Check pressure switch wiring.
2. Check inducer wiring.
3. Check for plugged or disconnected vacuum hoses.
B. Faulty pressure switch 1. Replace pressure switch.
C. Faulty pressure sensor,
located on the board
1. Replace board.
Air Sensor
Failure (EO5)
Pressure
Sensor
Reading High
The air sensor reading is too
high when the venter is off or
the air pressure switch open
when the sensor indicates
high flow.
The pressure switch MUST
close to initiate an ignition
sequence.
A. Faulty wiring or hose
connections
1. Check pressure switch wiring.
2. Check venter motor wiring.
3. Check for broken or disconnected vacuum hoses.
B. Blocked or improper
venting
1. Check air inlet and outlet for blockage.
2. Check venting configuration for excessive venting length,
improper sizing, etc.
C. Faulty pressure switch 1. Replace pressure switch.