Lennox G21Q3-80, Информация об устройстве

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Page 67
RECIRCULATION
CHECKS
NO YES
UNIT STARTS CLEAN BUT RUNS LESS THAN 10 SECONDS
IS FLAME SIGNAL PRESENT AND CORRECT?
CHECK WITH MICROAMP METER
NO YES
RESET UNIT IF LOCKED OUT, LISTEN FOR CHANGE IN SOUND
OF UNIT BEFORE IT STOPS.
UNIT LUGS" DOWN
BEFORE STOPPING.
UNIT STOPS WITHOUT ANY CHANGE
IN SOUND BEFORE STOPPING.
CHECK FOR RECIRCULATION OF EXHAUST GASES TO
AIR
INTAKE AT THE OUTSIDE TERMINATIONS OF PVC PIPING.
MODIFY OR COR
RECT
SEPARATION TO A
MAXIMUM OF 3".
ARE INTAKE AND EXHAUST PVC LINES TERMINATED
INTO A WINDOW WELL, ALCOVE OR CORNER WHERE
VARYING CONDITIONS CAUSE RECIRCULATION?
IF OUTSIDE TEMPERATURE IS LOW ENOUGH,
OBSERVE EXHAUST OUTLET VAPOR WHEN
UNIT IS RUNNING. RECIRCULATION WILL
EASILY BE SEEN.
MODIFY OR CORRECT
TERMINATIONS TO
ELIMINATE RECIRCULATION.
NO YES
ARE INTAKE AND EXHAUST PVC LINES SEPARATED
NO MORE THAN 3" AT OUTSIDE TERMINATION? DOES EXHAUST
TERMINATION EXTEND AT LEAST 8" PAST INTAKE TERMINATION?
MODIFY OR CORRECT
TERMINATIONS TO
ELIMINATE RECIRCULATION.
NOTE: RECIRCULATION IS ALSO POSSIBLE
WHEN EXHAUST C02 CONTENT IS ABOVE
10%. THIS IS DIFFICULT TO MEASURE AS
AN INDICATION IN THIS CASE IF UNIT WILL
ONLY RUN FOR 10 SECONDS OR LESS.
ARE LIMITS CUTTING OUT UNIT?
CHECK FOR OPEN LIMIT
IMMEDIATELY FOLLOWING UNIT
CUTOUT. SHUT OFF POWER
AND MAKE OHM METER CHECK.
NO YES
DETERMINE CAUSE OF LIMIT CUT OUT
AND CORRECT PROBLEM.
IS DIFFERENTIAL
SWITCH
CUTTING OUT UNIT?
MAKE OHM METER CHECK ACROSS
TERMINALS IMMEDIATELY AFTER
UNIT SHUTS OFF. METER READS
( )OHMS WHEN SWITCH
CUTS UNIT OUT.
8
NO YES
CHECK FOR PARTIAL BLOCKAGE
OF ALL PVC PIPING
& CONDENSATE LINE.
IF NO BLOCKAGE EXISTS
REPLACE DIFFERENTIAL
PRESSURE SWITCH
MAKE RECIRCULATION CHECKS.
IF RECIRCULATION IS NOT PRESENT, CHECK FOR ADEQUATE
GROUNDING OF UNIT AND PRIMARY CONTROL. IF OK, CHECK
PRIMARY CONTROL TIMING:
MONITOR MANIFOLD PRESSURE OR GAS VALVE COIL, PURGE BLOWER (120 VAC),
SPARK PLUG WIRE WITH SPARK TESTER AND FLAME SIGNAL. USE THE TIMING
CHARTS (FIGURE NO TAG ) TO DETERMINE IF THE CONTROL IS DEFECTIVE.
IF DEFECTIVE REPLACE
PRIMARY CONTROL.
5
4
3. REPLACE SENSOR IF
CRACKED?
2. ARE CRACKS PRESENT IN PORCELAIN?
1. WAS PLUG TIGHT WHEN REMOVED?
CHECK SENSOR WIRE
REPLACE IF DETERIORATED
& RETEST UNIT
REMOVE & CHECK SPARK PLUG (USE LENNOX
PART #20H43 OR 3/4" SPARK PLUG SOCKET).
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