Troubleshooting - Rheem 801T Series Installation Instructions Manual

FIGURE 33
DIAGNOSTICS FLOWCHART
NOTE: Always verify gas valve inlet and outlet gas
pressure .
1) Set FAN switch to "AUTO "
2) Set thermostat to call for heat (set temp. differ-
ential to greater than 10 F
PREPURGE
Does the IDM Energize?
IDM Runs for 30 sec. pre-purge ?
IGNITION TRIAL
IBM "ON" DELAY
Does Main Burner Light and stay lit?
Does IBM start on heat speed 20 seconds
STEADY HEAT
Does main burner remain lit until
Does thermostat maintain reasonable room
temperature near setpoint ?
END HEAT CALL
Set thermostat to off position (W to C = ØV)
POST-PURGE
Does gas valve shut off immediately?
Does IDM shut off after ten second post-purge?
IBM "OFF" DELAY
Does IBM shut off after a max. of 3 min?
STEADY OFF
Heat-mode troubleshootin g
50
INTEGRATED FURNACE CONTROL
TROUBLESHOOTING GUIDE
FLAME (AMBER) LED CODES
OFF = No Flame Presen t
RAPID BLINK = Unexpected Flame
SLOW BLINK = Marginal Flame Sense
STEADY ON = Normal Flame Sense
START
"FAULT DISPLAYED ?"
NO
NO
24V on W to IFC?
YES
YES
- Check line voltage at IDM.
- Check wires and connections between IDM and IFC.
- Ensure line voltage on IDM pins of IFC connector .
- Check IDM capacitor (90+ only) .
CHECK BLINK CODES
- Check for open limit or limit cir cuit.
Does IDM Run for 60 sec. and then off for Five minutes
NO
YES
FOR DIRECT SPARK IGNITION
- Check ignitor connected .
- Check ignitor wires.
Spark Ignitor Sparking?
- Check ignitor for fractures or cracking
NO
- Check ignitor placement .
YES
- If problem persists, check IFC*.
**
Is the gas valve energized?
NO
YES
NO
after burners light ?
NO
YES
- Check line voltage between "HEAT" and "NEUTRAL" on IFC.
- Check wires, connections, and continuity between IFC and IBM.
- Check IBM capacitor .
- Check IBM.
Is Limit cir cuit open or opening and closing?
NO
heat call ends?
Note: IFC Status LED should be blinking a Fault Code.
YES
YES
CHECK:
BLOCKED DRAIN - (fault "59" should be present)
AIRFLOW - ensure no restrictions, such as dirty filte r, dampers, closed registers, etc.
LIMITS - ensure good wire and connections between IFC and all limits. Make sur e
limits are not open when cir culating air temperature is within a specified range.
D
ROLLOUTS - ensure rollouts or overtemperature limits do not need to be reset. Make
sure no flame rollout in burner compartment due to blocked flu or heat exchanger .
OVERFIRE - ensure furnace is not overtemperature (temp rise is above stated range) .
Check gas valve, proper orifice size, gas pressure, etc.
Ensure thermostat is properly placed and not improperly affected by
NO
registers, fans, sunlight, heat through walls, pipes, or wires in walls .
YES
NO
Double check - Is W off at IFC?
NO
(W to C = ØV?)
YES
Ensure TSTAT is not in "FAN" position.
Is disply flashing a fault code
Is "FLAME" LED blinking or steady-on ?
NO
YES
NO
YES
END
REPEAT THIS PROCEDURE UNTIL TROUBLE-FREE OPERATION IS OBTAINED.
KEY TO ABBREVIATIONS
IBM = Indoor Blower Motor
IDM = Induced Draft Motor
IFC = Integrated Furnace Control
PS = Pressure Switch(es)
SE = Spark Electrode
DSI = Direct-Spark Ignition
YES "ATTEND TO FAULT"
- Check thermostat in "heat" mode,
NO
batte ry, wire, and connections.
- For Twinned units, check that both IFCs are set for "TWIN" and wire s
are connected between "TWIN" terminals .
- Check IFC*.
Check IFC*.
- For twinned units, ensure transformers are in phase.
(if out of phase, flame LED will be dim) .
NO - For non-twinned units, ensure "TWIN" is in the single (OFF) position.
- For Twinned units – ensure both IFC's have same part number .
Does IDM run
YES
indefinately .
- Check PS, PS Hoses, and wires.
- Check for blocked vent, excessive vent length or elbows, or
NO
- Check IDM wired correctly .
YES
- Ensure against excessive wind, which can open pressure switch.
- Check for intermittent P.S. operation.
- Check switches and hoses for water or moisture.
GO TO
YES I
If " I " did not
resolve issue.
NO
Is the IFC sensing a good flame: NOTE:
Flame sense light should be steady-on
when burners are lit. If flame LED blinking,
or off, flame sense is low or absent.
PROBLEM
STILL
PRESENT
- Check IFC*.
YES
Voltage present at gas valve?
NO
YES
Fault Code Present
SEE FAULT CODES
"FLAME" LED BLINKING
OR STEADY ON
GO TO
E
If "E" did not
resolve issue
Check IFC*.
CODE DESCRIPTION
O Standby
C Compressor on (cooling or heat pump heat)
H Gas heat on
F Continuous fan on
10 1 hour lockout
11 Failed ignition
12 Low flame sense
13 Flame lost
14 Unexpected flame
20 Twinning fault
22 Main limit open / HALC limit open
26 Line and neutral reversed
33 Mrlc (man. Reset limit cont.)(aka roll-out open)
55 Pres. Switch stuck closed, should be open
57 Pres. Switch stuck open, should be closed
58 Water Sensed Circuit Open
59 Water Sensed
61 Blower fault - blower unable to run
93 Internal control fault
- Check PS contact s
- Check wires for short.
H
- Check IFC*.
- Check switches and hoses for
water or moistur e
blocked heat exchanger .
- Check gas supply and manifold pressure.
- Ensure L1 and Neutral not swapped on IFC and junction box.
- Check igniter alignment .
- Check orifice or other restrictions to gas flo w.
- Check flame sense rod (clean with scotch brite pad).
- Check flame carry over.
- Check wires, continuity , and connection between IFC and gas valve.
- Ensure 24 V between appropriate pins on connector of IFC.
Ensure manual switch on valve is in the "ON" position.
- Did a pressure switch open during ignition trial? If yes, go to F
I - Did a limit open during ignition trial? If yes, go to D
NOTE: If IFC goes into lockout ("ST ATUS LED will blink code "1"), shut
off main power to unit, wait 30 seconds and then reset power .
YES
PS dropping out ?
YES
GO TO
NO
F
CHECK:
- grounding on IFC and unit.
- check for proper polarity between L1 & neutral.
- flame sense rod (clean if necessar y).
- wire continually between flame sense rod and appropriate pin of
connector on IFC
- flame carries across all burners, and all burners stay lit.
- Check heat anticipator setting. Furnace may need an isolation relay.
- Check installation instructions under section titled "Isolation Relay" for
details .
- Verify correct furnace sizing.
- Check gas valve. *Most failures are not due to the IFC. Doubl e
check all other possibilities, including the
ground connection or wire connections, before
replacing the IFC.
**System will attempt to light 4 times. Voltage
is present at gas valve for only 7 seconds dur -
ing each trial for ignition. The entire system will
go into a 1 hour lockout after 4 attempts.
G
F
NO
Check IFC*
E
ST-A1194-23-03