Lennox G21Q Series Unit Information

Page 60
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NO YES
NO YES
REFER TO INSTALLATION INSTRUCTIONS: ARE IN
TAKE & EXHAUST LINES PROPERLY SIZED & AP
PLIED WITHIN LENGTH, DIAMETER & ELBOW LIMITS?
YES NO
YES
NO YES
YES NO
IS GAS SUPPLY NATURAL OR L.P.?
L.P. NATURAL
HAS L.P. CONVERSION KIT
BEEN INSTALLED?
IF NOT, INSTALL KIT.
IS GAS SUPPLY ON?
1. CHECK SUPPLY VALVE.
2. CHECK STOP VALVE AT UNIT.
3. CHECK MANUAL LEVER OR SWITCH
ON GAS VALVE IN UNIT.
CHECK FOR LEAKS IN GAS SUPPLY
PIPING & REPAIR IF NEEDED.
AIR IN GAS PIPING?
BLEED AIR BUY RUNNING UNIT THROUGH SEVERAL
TRIES FOR IGNITION. BREAK & REMAKE THERMOSTAT
DEMAND TO RESTART IGNITION SEQUENCE AT 2 TO 3
MINUTE INTERVALS.
CAUTIONDO NOT USE MATCH OR FLAME
TO CHECK FOR GAS LEAKS.
GAS
CHECKS
CHECK FOR LEAKS IN UNIT MANIFOLD PIPING.
LEAKS NO LEAKS
REPAIR LEAKS
& RETEST.
VISUALLY CHECK OUTSIDE TERMINATIONS OF
INTAKE & EXHAUST PVC PIPING FOR OBSTRUCTIONS.
VISUALLY CHECK CONDENSATE DRAIN FOR OBSTRUCTIONS.
CORRECT PIPING
ERRORS & RE
TEST.
TURN OFF GAS TO UNIT.
CHECK PURGE BLOWER FOR BINDING
OR MECHANICAL DAMAGE.
BREAK & REMAKE THERMOSTAT DEMAND
TO INITIATE CONTROL SEQUENCE.
IS120VAC PRESENT ACROSS PURGE
BLOWER MOTOR TERMINALS?
NO YES
IS 120VAC PRESENT BETWEEN
JP1−6 AND JP1−5?
DOES PURGE BLOWER RUN?
REPLACE
PURGE BLOWER.
REPLACE
PRIMARY CONTROL.
CHECKOUT
WIRING
CONNECTIONS
& REPAIR.
IS GAS VALVE ACTUALLY OPENING?
DETERMINE BY CHECKING FOR MANIFOLD
PRESSURE DURING TRIALS FOR IGNITION.
REPLACE GAS VALVE.
CORRECT
GAS PRES
SURE.
AIR
CHECKS
REMOVE AIR INTAKE CHAMBER COVER
(USE CARE TO PREVENT DAMAGE TO COVER GASKET).
8
9
CHECK GAS SUPPLY LINE PRESSURE
IS PRESSURE WITHIN UNIT NAMEPLATE LISTING?
GAS, AIR and SPARK CHECKS
NOTE− Numbered steps refer to illustrations on page 61.
NOYES
TO CHECK FOR SPARK, USE EXTERNAL PLUG CONNECTED
TO SPARK WIRE. MAKE SURE SPARK GROUND STRAP
IS FIRMLY GROUNDED TO UNIT.
DANGERSHOCK HAZARD. TURN OFF GAS SUPPLY BEFORE TESTING.
DO NOT HANDLE SPARK PLUG OR WIRE DURING TEST.
RESTART IGNITION SEQUENCE
(BREAK & REMAKE THERMOSTAT DEMAND).
AFTER 30 TO 35 SECONDS PRE−PURGE, IS SPARKING PRES
ENT
FOR APPROXIMATELY 7 SECONDS DURING IGNITION TRIAL?
CHECK FOR IGNITION WIRE(FOR BREAKS OR SHORTS TO
GROUND)
& FOR LOOSE CONNECTIONS TO CONTROL AND/OR SPARK PLUG.
MAKE OHMMETER CHECK.
BREAK & REMAKE THERMOSTAT DEMAND
TO INITIATE CONTROL SEQUENCE.
REPLACE
PRIMARY CONTROL.
NO SPARKSPARK
REPLACE AIR INTAKE CHAMBER COVER. TURN ON GAS & RESTART UNIT.
PUT PLUG BACK IN UNIT. TURN ON POWER.
(LEAVE GAS OFF) & RETEST FOR SPARK.
4. REPLACE AND/OR REGAP PLUG IF REQUIRED.
3. IS PLUG GAPPED PROPERLY?
2. ARE CRACKS PRESENT IN PORCELAIN?
1. WAS PLUG TIGHT WHEN REMOVED?
REMOVE & CHECK SPARK PLUG (USE 3/4" SPARK PLUG SOCKET).
TURN OFF POWER.
SPARK CHECKS
CAUTIONHIGH VOLTAGE
10

Lennox G21Q Series Specifications

General

Brand	Lennox
Model	G21Q Series
Category	Industrial Equipment
Language	English