Lennox G21Q3-80 Unit Information Download | Manualshive

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TABLE 8

G21Q/GSR21Q BLOWER RATINGS

120V 1PH

BLOWER MOTOR

HP

Q3

Q4

Q5

CAP

3/4

1/2

1/3

5MFD 370V

7.5MFD 370V

40MFD 370V

Page 29

O − Blower Motors and Capacitors

(Q" Units)

All G21/GSR21 Q"
units use direct drive
blower motors. All Q"
motors are 120V per
manent split capacitor
motors to ensure maxi
mum efficiency. See
table 8 for ratings. Multispeed Q" blower motors are factory
wired for low speed (red tap) heating, GSR21Q380 units are
wired for medium speed (yellow) tap heating. See table 9.

1 − Blower Speed Taps Q" Units

Leadless Motors Only

Some G21/GSR21 "Q" units will be equipped with lead
less blower motors. Blower speed tap selection on lead
less motors is accomplished by changing taps on the
blower motor harness connector. Disconnect harness
connector from motor to expose speed selectors. See
table 9 for leadless motor blower speed selection.

BLOWER SPEED SELECTION LEADLESS MOTORS

Q340, Q360

UNIT

Factory Connected

Speed Taps

Motor Speeds

Available

Cool

Heat

4
3

3

2

4

4

6

5

BLOWER SPEED SELECTION
HI

LOW

2

3

4

5

2

3

4

5

6

SPEE

D

4
5

TABLE 9

Q380
Q3100

Q4/5, Q5

TAPS

5

4

Q4

2

3

4

3

TABLE 10

To Change Blower Speed Q" Units With

Leadless Motors Only:

1 − Turn off electric power to furnace.
2 − Lift left side filter over left support angle. For easy han

dling, hold filter at center bottom.

3 − Grasp blower motor harness connector located on

back of motor. Depress lock tab and pull connector
from motor.

4 − Pull harness connector and wires through blower ac

cess panel opening.

5 − Select desired heating and cooling speeds.(Red=

heating, Black=cooling, White=common). See table
9.

6 − Depress harness connector tab to release wire termi

nal. Select connector location for new speed (refer to
unit wiring diagram). Insert wire terminal until it is se
curely in place. See figure 32.

7 − Replace harness connector to motor.

BLOWER SPEED TAP SELECTION Q"

HARNESS

CONNECTOR

MOTOR

DEPRESS TAB TO RELEASE
WIRE TERMINAL. SELECT CON
NECTOR LOCATION FOR NEW
SPEED (REFER TO UNIT WIR
ING DIAGRAM). INSERT WIRE
UNTIL IT IS SECURELY IN
PLACE.

FIGURE 32

2 − Blower Speed Taps Q" Units

leaded Motors Only

G21/GSR21"Q"−9 models will be equipped with leaded mo
tors. Blower speed tap selection on leaded motors is ac
complished by changing speed taps. Speed taps are lo
cated in the control box. Simply remove control box cover
and disconnect current tap, then rewire tap selected. See
table 10 for color coded speed taps.

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Summary of Contents for G21Q3-80

Page 1: ...l or fixed 24 VAC or VDC signal These signals are gener ated by optional controls such as the Harmony zone control system Efficiency Plus Humidity Control CCB1 or a thermostat A PWM signal is generated by the Harmony zone control system A fixed DC signal is generated by the Efficiency Plus Humidity Control CCB1 and a 24 VAC signal is generated by a thermo stat The Harmony zone control system produ...

Page 2: ...nal Charts Page 66 68 VIII Wiring and Sequence of Operation G21Q Page 69 70 GSR21Q Page 71 72 G21V Page 73 74 GSR21V Page 75 76 G21Q W GC3 Page 77 78 G21Q W GC1 Page 79 80 GSR21Q W GC3 Page 81 82 GSR21Q W GC1 Page 83 84 G21V W GC1 Page 85 86 G21V W GC3 Page 87 88 GSR21V W GC1 Page 89 90 GSR21V W GC3 Page 91 92 Jumper Summary Tables Page 93 99 CAUTION Electrostatic discharge can affect electronic c...

Page 3: ... ICM2 BLOWER MOTOR HEAT EXCHANGER ASSEMBLY IGNITION CONTROL GAS FLAPPER VALVE ORIFICE ASSEMBLY ICM1 BLOWER MOTOR IGNITION CONTROL PARTS ARRANGEMENT GSR21 DOWNFLOW HORIZONTAL UNIT AVAILABLE ELECTRONICALLY CONTROLLED BLOWER MOTOR V MODELS AIR INTAKE PVC CONNECTION EXHAUST OUTLET CONTROL BOX HEAT EXCHANGER ASSEMBLY DOOR INTERLOCK SAFETY SWITCH EXPANSION TANK GAS VALVE AIR FLAPPER AND HOUSING BLOWER C...

Page 4: ...s equipped with conventional multi speed blower motor Model No G21Q3 80 G21Q4 80 G21Q5 80 G21Q3 100 G21Q4 5 100 Input Btuh 80 000 80 000 80 000 100 000 100 000 Output Btuh 73 000 73 000 74 000 93 000 95 000 A F U E 93 9 93 9 93 2 94 9 94 5 California Seasonal Efficiency 90 1 88 9 88 3 90 8 89 6 Temperature rise range F 45 75 40 70 35 65 55 85 40 70 High static certified by A G A in wg 50 50 50 50 ...

Page 5: ... orifice furnished as standard with unit for field changeover Convertible gas valve requires simple adjustment without adding any parts See installation instructions SPECIFICATIONS units equipped with electronically controlled blower motor Model No G21V3 60 G21V3 80 G21V5 80 G21V5 100 Input Btuh 60 000 80 000 80 000 100 000 Output Btuh 55 000 73 000 74 000 95 000 A F U E 94 3 94 5 93 4 94 5 Califo...

Page 6: ...hangeover Annual Fuel Utilization Efficiency based on D O E test procedures and according to F T C labeling regulations Isolated combustion system rating for non weatherized furnaces LPG orifice furnished as standard with unit for field changeover Convertible gas valve requires simple adjustment without adding any parts See installation instructions BLOWER DATA units equipped with conventional mul...

Page 7: ... 2420 2310 2110 1880 1670 10 2390 2270 2080 1860 1640 15 2350 2240 2050 1830 1620 20 2320 2210 2020 1800 1590 25 2280 2170 1990 1770 1570 30 2250 2140 1960 1740 1540 40 2180 2060 1890 1680 1480 50 2100 1980 1810 1610 1420 60 2005 1890 1740 1530 1350 NOTE All cfm data is measured external to unit with the air filter in place GSR21Q3 50 BLOWER PERFORMANCE External Static Air Volume cfm Various Speed...

Page 8: ...r in place GSR21Q4 5 100 BLOWER PERFORMANCE External Static Air Volume cfm Various Speeds Pressure in wg High Med High Medium Med Low Low 0 2275 2140 1940 1725 1520 05 2245 2110 1915 1700 1490 10 2215 2075 1885 1675 1465 15 2185 2040 1860 1645 1435 20 2150 2005 1830 1620 1410 25 2115 1970 1805 1590 1380 30 2075 1935 1775 1560 1350 40 1990 1870 1710 1500 1290 50 1925 1800 1645 1435 1235 60 1835 173...

Page 9: ...TION VSP2 1 JUMPER POSITION SETTING 1 2 3 4 1 2 3 4 1 2 3 4 520 670 800 960 1110 1220 1340 1420 1110 1210 1310 1420 NORM 480 600 740 880 1070 1160 1270 1300 1000 1100 1200 1280 420 550 650 770 950 1040 1150 1170 900 1000 1100 1160 NOTE ADJUST position on JPB1 NORM or determines the row of CFM available to use NOTE All air data is measured external to the unit with the air filter in place Blower ma...

Page 10: ...20 2010 2050 2100 2100 NOTE All air data is measured external to the unit with the air filter in place Blower maintains a constant CFM throughout a range of varying static pressures GSR21V3 80 BLOWER PERFORMANCE FACTORY BLOWER SPEED SETTINGS GSR21V3 80 Low Speed Heat Cool tap 3 High Speed Cooling tap 11 High Speed Heat tap 7 External Static Air Volume cfm Various Speeds Pressure in wg Tap 1 Tap 2 ...

Page 11: ...LATION HEATING COMPARTMENT PURGE BLOWER DIFFERENTIAL PRESSURE SWITCH SPARK PLUG SENSOR ACCESS PANEL UNIT COMPONENTS HORIZONTAL REVERSE FLOW V UNITS ICM2 SHOWN WITH VSP2 1 PURGE BLOWER AIR INTAKE PVC CONNECTION IGNITION CONTROL DIFFERENTIAL PRESSURE SWITCH EXPANSION TANK GAS VALVE EXHAUST OUTLET AIR FLAPPER VALVE MODULATION LIMIT CONTROL BLOWER GAS FLAPPER VALVE ORIFICE ASSEMBLY TERMINAL STRIP TB1 ...

Page 12: ...izontal installa tions and in the upper right hand corner of the heating compartment in reverse flow applications GSR21Q CONTROL BOX TRANSFORMER T1 TERMINAL STRIP TB1 TERMINAL BLOCK TB2 DOOR INTERLOCK SAFETY SWITCH S51 INDOOR BLOWER RELAY K3 FAN TIMING CONTROL A28 GSR21V CONTROL BOX TRANSFORMER T1 TERMINAL STRIP TB1 TERMINAL BLOCK TB2 FIGURE 1 GROUNDING LUG GROUNDING LUG DOOR INTERLOCK SAFETY SWIT...

Page 13: ...er from LOW to HIGH speed in cooling mode DS is the PWM pulse width modulation in put in zoning applications that use Harmony II zon ing system NM This terminal is used for non zoning Non Harmony non modulating applications where heat exchanger mod ulation is NOT desired The heat demand from the ther mostat should be wired to this terminal instead of W1 CAUTION For units with the IMC2 motor do not...

Page 14: ...mostat demand It is built into the ignition control on all units equipped with GC 3 or Johnson ignition control On GC 1 equipped units it is externally mounted For GC 1 equipped units Watchguard is enabled with a heating demand After one hour unit locked out or run ning of continuous thermostat demand watchguard opens for two minutes then closes remaking thermostat demand W1 This resets electronic...

Page 15: ...P1 con trols the fan on and fan off timings Fan on timings are pre set and non adjustable Fan off timings are adjustable Fan on timing is the amount of time the unit operates before the blower is started This period allows for heat exchanger warm up The fan on timing is pre set at 45 seconds and is not adjustable Fan Off timings time that blower operates after heating demand has been satisfied are...

Page 16: ...M W2 PIN 7 24VAC INPUT SIGNAL FROM EXTERNAL LIMIT PIN 8 24VAC POWER FOR VSP1 PIN 9 24VAC INPUT FROM GAS VALVE PIN 10 24VAC OUTPUT FROM VSP1 TO IGNITION CONTROL A3 PIN 11 24VAC INPUT FROM FAN LIMIT CONTROL PIN 12 24VAC INPUT FROM FAN LIMIT CONTROL 1 3 6 9 12 IMPORTANT 24 VAC half wave rectified DC pulse when mea sured with a meter may appear as a lower or high er voltage depending on the make of th...

Page 17: ...oss J73 pins 13 to 1 and 6 to 1 is 24VAC as shown here Refer to unit wiring diagram Voltage across J46 pins 6 to 3 and 1 to 3 is half rectified AC as shown here Refer to unit wiring diagram Voltage across J73 pins 4 to 1 is approximately 15 20VDC straight voltage if CCB is used If Harmony is used a voltage of 0 25VDC should be present If CCB or Harmony is not used pin 4 to 1 voltage is 21VAC Appro...

Page 18: ...mode the highest speed obtainable is the same as the highest cooling speed selection Also the heating speed heat jumper position is only used when the primary limit has been tripped In non zoning applications refer to the section on the VSP2 1 control Jumper Settings IMPORTANT Before changing jumper setting make sure the motor has completely stopped Any jumper set ting change will not take place w...

Page 19: ...ection for details f FAN OFF Fan OFF timings time that the blower operates after the heat demand has been satisfied are determined by the ar rangement of a jumper on the VSP2 1 board See fig ure 15 To adjust fan OFF timings gently disconnect the jumper and reposition it across pins corresponding with the new timing Fan OFF time is factory set at 270 seconds Fan ON time is factory set at 45 seconds...

Page 20: ... not desired For units equipped with the VSP1 and W2 and HB jumpered together the blower will operate on high speed tap Regardless of VSP used do not change the factory modulation settings S78 is set to prevent the unit from tripping limit S10 110 F 140 F MODULATION CONTROL S78 V MODELS GSR21V5 80 UNIT MODULATION SETTING TABLE 6 GSR21V 100 G21V3 60 G21V3 80 G21V5 80 110 F G21V5 100 GSR21V3 80 OPEN...

Page 21: ...oses the blower is forced to operate 1 GSR21 Q Applications S71 S71 is a normally open SPST self resetting control wired in parallel with blower relay K36 1 On a tem perature rise S71 closes energizing blower B3 on heating tap speed 2 GSR21 V Applications S71 S71 is a normally open SPST self resetting control wired in series with 24 VAC from transformer T1 S71 closes and S78 opens on a temperature...

Page 22: ...n Control Troubleshooting Flowchart in back of manu al The GC 3 and G891 do not have Safety Dormant Lockout circuit Watchguard All G21 GSR21 units are equipped with a watchguard circuit The GC 1 uses a separate external watchguard WG1 control board A18 located above the control box The GC 3 and G891 ignition control incorporate this function The watchguard feature serves as an automatic reset de v...

Page 23: ...barbed nail Like the later GC 3 controls the G891 energizes the spark for a full eight seconds GREEN LED 1 2 3 4 5 6 NEUTRAL SENSE TERMINAL BARBED NAIL CONNECTOR TRANSFORMER G891 IGNITION CONTROL BARBED NAIL CONNECTOR J72 CONNECTOR FIGURE 20 1 24 VAC FROM TSTAT W 2 COMMON 3 24 VAC TO GAS VALVE 4 24 VAC INPUT FROM TRANSFORMER T1 5 120 VAC TO PURGE BLOWER 6 120 VAC INPUT 4 Ignition Control Functions...

Page 24: ... GC 3 and G891 seconds gas valve and ignition spark are energized for 8 seconds 4 If no ignition is sensed purge blower continues to run 5 After additional 30 seconds GC 1 and G891 25 seconds GC 3 ignition retrial takes place for another 8 seconds 6 If no ignition is sensed purge blower continues to run for another 30 seconds GC 1 and G891 25 seconds GC 3 7 This sequence is repeated for five trial...

Page 25: ...the elbow gas flapper as sembly must be removed and replaced with the orifice pro vided in the kit GSR21 50 80 use orifice provided with unit See figure 24 A spring behind the adjusting screw and regulator cover screw must be replaced by a heavier spring also included in the kit GSR21 50 and 80 units regulator screw must be rotated so that end labeled LP points toward regulator See figures 24 and ...

Page 26: ...o troubleshooting section for specific information about flapper valve inspection and conditions requiring re placement IMPORTANT Disconnect gas pipe at union Tighten until bush ing seats in orifice housing and gas pipe is in verti cal position 2 Orifice WARNING Standard atmospheric burner orifices or orifice blanks cannot be used as replacements in G21 GSR21 units Each G21 GSR21 unit uses only on...

Page 27: ...n The sensor is the top plug and is longer than the spark plug The spark plug is in the lower position Plugs cannot be interchanged due to different thread diameters M Combustion Chamber Heat Exchanger Assembly Figures 30 and 31 1 Combustion Chamber The combustion chamber has gas and air intake manifolds See figures 30 and 31 for exact location Exhaust gas leaves through the tailpipe at the top of...

Page 28: ...K PLUG VALVE BODY AIR FLAPPER VALVE ASSEMBLY ORIFICE INSIDE GAS INTAKE MANIFOLD FLAPPER VALVE ASSEMBLY EXPANSION TANK GAS VALVE EXHAUST DECOUPLER COIL INLET MANIFOLD RESONATOR AIR INTAKE MANIFOLD CONDENSER COIL TAILPIPE EXHAUST OUTLET MANIFOLD RUBBER ISOLATION MOUNTS 4 ELBOW PRESSURE TAP Combustion Procedure in G21 GSR21 Units 1 Gas flows through the valve expansion tank flapper valve and orifice ...

Page 29: ...3 TABLE 10 To Change Blower Speed Q Units With Leadless Motors Only 1 Turn off electric power to furnace 2 Lift left side filter over left support angle For easy han dling hold filter at center bottom 3 Grasp blower motor harness connector located on back of motor Depress lock tab and pull connector from motor 4 Pull harness connector and wires through blower ac cess panel opening 5 Select desired...

Page 30: ...ad The controller uses sensing devices to know what position the rotor is in at any given time By sensing the position of the rotor and then switching the motor windings on and off in sequence the rotor shaft turns the blower G21V GSR21V series blower motor ratings are listed in table 11 All G21V GSR21V blower motors use single phase pow er An external run capacitor is not used The motor uses per ...

Page 31: ...nside the controller If the disconnect switch is bounced when the disconnect is closed the disconnect contacts may become welded Try not to bounce the disconnect switch when applying power to the unit The DC filter capacitors inside the controller are connected electrically to the speed tap wires The capacitors take approximately 5 minutes to discharge when the disconnect is opened For this reason...

Page 32: ...or windings O volts 325VDC One revolution O volts 325VDC O volts 325VDC WINDING 1 WINDING 2 WINDING 3 O volts 325VDC O volts 325VDC O volts 325VDC ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ WINDING 1 WINDING 2 WINDING 3 O volts 325VDC O volts 325VDC O volts 325VDC Motor speed is determined by the size ...

Page 33: ...o not attempt to measure this voltage Follow diagnostic procedures outlined in this manual to determine if motor and VSP1 are operating properly a Blower Speed Taps V Units Table 12 shows the factory set blower speeds All speeds shown are minimums Do not change motor taps to oper ate at speeds lower than the minimum or higher than the maximum Blower motor and cfm performance ratings are listed in ...

Page 34: ...s forces the blower to run on the high speed cool tap DS1 and DS3 LEDs are lit to in dicate blower operation on the high speed cool ing tap 2 Non Zoned Units With Two Speed Compressor Without CCB1 IMPORTANT Y2 must be jumpered to DS in two speed non zoned applications when CCB1 is not used The ON OFF LED DS1 is lit to indicate the blow er is operating on the low speed heat cool tap DS1 is energize...

Page 35: ...led blower mo tor is improperly or inadequately grounded it may cause tele vision interference commonly known as RFI or radio frequen cy interference This interference is caused by internal switching frequencies of the motor controller see figure 41 TV interference may show up as small specks or lines which randomly appear on the TV screen accompanied by pops or clicks in the sound Before at tempt...

Page 36: ... is operating NOTE In Harmony II zoning ap plications HTG BLOWER jumper must be in position 2 ZONED APPLICATIONS The blower speed is controlled by the PWM pulse width modulation signal sent from the control center of the zoning system to the terminal strip s DS terminal HI LOW LED DS1 and ON OFF LED DS3 are lit to indicate the blower is operating ZONED APPLICATIONS The blower speed is controlled b...

Page 37: ...SOMODE PADS 4 COUPLING ALL G21 GSR21 80 100 UNITS REQUIRE THE USE OF MUFFLERS MUFFLERS ARE RECOMMENDED OPTIONS ON ALL OTHER UNITS MUFFLER MUFFLER SUPPLY RETURN INSTALLATION PROCEDURES OUTLINED IN THIS MANUAL ARE PRESENTED AS RECOMMENDATION ONLY AND DO NOT SUPERSEDE OR REPLACE LOCAL OR STATE CODE IF LOCAL OR STATE CODES DO NOT EXIST THE PROCEDURES OUTLINED IN THIS MANUAL ARE RECOMMENDED ONLY AND DO...

Page 38: ...FACE 1 INCH THICK INSULATION INSULATED PAST FIRST ELBOW FLEXIBLE BOOT IN DUCT OR PLENUM SUPPLY AIR FLEXIBLE BOOT IN PLENUM OR DUCT RETURN AIR MUFFLER MUFFLER ALL G21 GSR21 80 100 UNITS REQUIRE THE USE OF MUFFLERS MUFFLERS ARE RECOMMENDED OPTIONS ON ALL OTHER UNITS INSTALLATION PROCEDURES OUTLINED IN THIS MANUAL ARE PRESENTED AS RECOMMENDATION ONLY AND DO NOT SUPERSEDE OR REPLACE LOCAL OR STATE COD...

Page 39: ...N ALL OTHER UNITS INSTALLATION PROCEDURES OUTLINED IN THIS MANUAL ARE PRESENTED AS RECOMMENDATION ONLY AND DO NOT SUPERSEDE OR REPLACE LOCAL OR STATE CODE IF LOCAL OR STATE CODES DO NOT EXIST THE PROCEDURES OUTLINED IN THIS MANUAL ARE RECOMMENDED ONLY AND DO NOT CONSTITUTE CODE RETURN AIR PLENUM 1 5 TO 3 LB DENSITY MATTE FACE 1 INCH THICK INSULATION INSULATED PAST FIRST ELBOW SUPPLY AIR PLENUM 1 5...

Page 40: ...AR PANEL GAS PIPING FIGURE 46 GAS CONNECTOR A G A UNITS ONLY RIGHT WRONG FIGURE 47 WARNING The flexible gas connector if used must be mounted external to the unit The connector must hang freely and must not contact or rub outside objects The flexible connector must not enter the unit See figure 46 I Muffler All G21 GSR21 80 100 units require the use of mufflers Muf flers are optional on all other ...

Page 41: ...where the unit is mounted horizontally a drain pan can be used to catch potential condensate leakage Q Drip Leg Assembly G21 only Figures 50 and 51 A drip leg must be used to remove condensate and exhaust from the unit A drip leg assembly may be used on the G21 only If unit condensate line is clogged or obstructed ex cess water may shut down the unit G21 drip leg assem blies may contain a threaded...

Page 42: ...NSATE DRAIN 1 2 X 5 1 2 PVC VENT 1 1 2 PVC EXHAUST NIPPLE BALL FLOAT CONDENSATE TRAP GSR21 DOWNFLOW APPLICATION FIGURE 54 Service Procedures for Ball Float Condensate Trap 1 Remove screws and clamps from condensate trap as sembly 2 Lower trap assembly from housing Care should be taken not to crack seal from housing to exhaust pipe and compression coupling 3 Disconnect trap assembly from condensate...

Page 43: ... 1 2 2 1 2 3 2 2 2 2 2 2 1 2 2 1 2 2 1 2 2 1 2 3 2 2 2 2 3 2 1 2 2 1 2 2 1 2 2 1 2 3 2 2 2 3 3 2 1 2 2 1 2 2 1 2 2 1 2 3 2 2 3 3 3 2 TABLE 14 Refer to GSR21 GSR14 Exhaust Intake Air Termination Kits installation instructions for installation procedures which meet local and national codes IMPORTANT The exhaust line must be reduced at wall termina tion to 1 1 2 T Standard Intake Exhaust Termination ...

Page 44: ...OSED TO THE ELE MENTS MUST BE PAINTED OR WRAPPED TO PREVENT DETERIORATION TOP VIEW WALL TERMINATION FIGURE 59 2 X 1 1 2 PVC REDUCER SIDE VIEW WALL TERMINATION 12 ABOVE AVERAGE SNOW ACCUMULATION UNCONDITIONED SPACE 12 MAX 8 MIN 1 2 ARMAFLEX INSULATION 1 2 ARMAFLEX INSULATION IN UN CONDITIONED SPACE PROVIDE SUPPORT FOR INTAKE AND EXHAUST LINES EVERY 3 FEET OUTSIDE WALL REDUCE TO 1 1 2 1 1 2 PVC TOP ...

Page 45: ...lable from Lennox Repair Parts No P 8 5069 C Fan Controls Limit Controls Check fan and limit controls for proper operation and set ting For settings refer to the sections on the VSP2 Blower Control Board Fan Timing Control A28 and Limit Control Modulation Limit Control in this manual D Purge Blower Periodically inspect and clean purge blower wheel 1 Disconnect power to the unit 2 Remove upper heat...

Page 46: ...ug and sensor wires from plugs in combustion chamber Access plate is provided 18 Remove vest panel 19 From underside of blower deck remove four nuts hold ing rubber heat train mounts 20 Lift heat train from unit 21 Backflush heat train with a soapy water solution or steam clean IMPORTANT If unit is backflushed with water make sure all wa ter is drained from heat train before replacing Use papers o...

Page 47: ...tional SEE CAUTIONS AND WARNINGS BELOW Check the manifold pressure immediately after the gas valve fully opens 6 The gas valve can be adjusted using the regulator adjust ment screw This screw is located under the dust cover screw on the face of the valve next to electrical terminals and manual on off knob Refer to figure 24 WARNING Disconnect heating demand as soon as an accu rate reading is obtai...

Page 48: ...ead on the meter G891 flame signal is 1 2 2 2 microamps therefore a read ing of 1 2 2 2 volts should be read on the meter The transducer plugs into the meter See figure 66 for proper use of transducer 1 Set the volt meter to the DC voltage scale Insert transducer into the VDC and common inputs Ob serve correct polarities Failure to do so results in neg ative values 2 Turn off supply voltage to con...

Page 49: ...d H Testing Exhaust CO2 CO Content Use the following as a guide to test for abnormally high CO2 CO content To Measure CO2 CO Content 1 Drill size R or 11 32 in hole on top of the exhaust out let PVC elbow inside unit cabinet and tap 1 8 27 NPT as shown in figure 67 This hole is used as the CO2 CO test port 2 Install a hose barb into the test port See figure 67 CO2 CO SAMPLING PROCEDURE GSR21 SHOWN...

Page 50: ... for 15 minutes If accurate input measurements are required the following pro cedure may be used Accurate input measurements requires time for the unit to run in Run in time allows flapper valves to seat and combustion to clean the protective layer of oil residue that may be present from inside surfaces of the heat exchanger assembly This process stabilizes combustion rate and may take one to two ...

Page 51: ...mber compartment if necessary 2 Do not remove air flapper valve unless it is suspected of being faulty If valve must be removed carefully remove the eight screws holding air intake flapper valve to valve body DO NO TURN OR REMOVE CENTER SCREW Remove valve from unit CAUTION DO NOT DROP 3 EXTREME CARE SHOULD BE TAKEN WHEN DISAS SEMBLING INTERNAL COMPONENTS OF THE VALVE If taken apart plates could be...

Page 52: ...After unit cycles off residual heat in combustion chamber will transfer back to valve causing it to become very hot Allow it to cool 10 to 15 minutes before handling The blower can also be run to cool air intake FIGURE 71 VALVE BODY THERMOPLASTIC ELASTOMER BACK PLATE FLAPPER COVER SCREWS 8 SCREW TORQUE TO 10 1 IN LBS STAMPS IN SAME QUADRANT AND FACING AWAY FROM UNIT NUT CENTER PLATE PPS THERMOPLAS...

Page 53: ...be re placed 4 Check for the required clearance between the flapper and valve body Required clearance values for G21 GSR21 units are 0 024 0 003 in Use a feeler gauge starting small and working up to the clearance di mensions until the gauge is just about snug Do not force gauge Check clearance around the valve in sev eral places If the valve is out of the required clear ance dimension given in fi...

Page 54: ...SCRIBES THE UNIT S PROBLEM FOLLOW THE FLOW CHART STEP BY STEP At any point a NO answer is reached and a repair is made reassemble the unit and retest for opera tion If unit does not operate recheck that point and then continue through the chart Occasionally more than one specific problem may exist When troubleshooting a unit be sure that all basic checks are covered carefully Double check your dia...

Page 55: ...M2 check out Follow testing procedures outlined in the instructions provided with the kit The testing procedures are different than those listed below If not using the kit to test the motor follow the procedure below 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 3 4 5 6 7 8 9 10 11 12 13 J46 J46 J46 FIGURE 76 C ICM1 Does Not Run If the motor does not run the problem could be with...

Page 56: ...ly a Check for shorted 24 VAC control circuit wir ing Repair or replace if necessary 2 Is the gas valve stuck open G Abnormal Sounds Corrective action is required if abnormal hissing sounds around the air decoupler are heard This problem may be caused by 1 Air leakage around decoupler box cover 2 Air leakage around air decoupler box cover mount ing screws 3 Air leakage out of the purge blower lead...

Page 57: ...KE SURE UNIT IS OUT OF POST PURGE NO YES TURN OFF UNIT POWER AT DISCONNECT FOR AT LEAST 3 SECONDS THEN TURN POWER BACK ON ALLOW 3 SECONDS FOR CONTROL TO POWER UP IS RED DIAGNOSTIC LED LIT UNIT WAS IN LOCKOUT LIT YES CONTROL SHOULD OPERATE PROPERLY PROCEED TO UNIT WILL NOT RUN GAS CHECKS AND SPARK CHECKS TO RULE OUT OTHER POSSIBILITIES NO CONTROL SHOULD OPERATE PROPERLY PROCEED TO ELECTRICAL CHECKO...

Page 58: ...w 3 sec onds for control to power up Control should operate properly proceed to UNIT WILL NOT RUN GAS CHECKS AND SPARK CHECKS to rule out other possibilities If 24 VAC is present between JP72 4 and Common and LED is not lit re set power to control If control still does not operate replace control NO LIT YES Proceed to ELECTRICAL CHECKOUT Does control A3 have 24VAC supplied between pins JP72 4 and ...

Page 59: ...Y ON INTERLOCK SWITCH CHECK FOR 120VAC POWER TO UNIT ADEQUATE GROUNDING GROUNDING REQUIRED FOR PROPER OPERATION OF IGNITION SYS TEM SYSTEM MAY BE LOCKED OUT TURN THERMOSTAT HEATING DEMAND OFF AND ON AGAIN NOTE CONTINUE THROUGH TROUBLESHOOTING FLOW CHART TO LOCATE REASON FOR LOCKOUT SET FOR HEAT DEMAND 1 2 3 4 5 IS UNIT FUSE BLOWN YES NO RE PLACE FUSE REPLACE TRANSFORMER NOTE Numbered steps refer t...

Page 60: ...EPLACE 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...

Page 61: ...ECTION FOR METER LEAD TEST POINT ORANGE LIMIT WIRES PURGE BLOWER WHITE NEUTRAL RED NOTE RED WIRE GOES TO PRIMARY CONTROL HARNESS JP72 5 PRIMARY CONTROL WIRING HARNESS PLUG JP72 CHAMPION FI 21500 or equivalent only TO FLUE CHECK VOLTAGE AT TERMINAL AND CHECKING THERMOSTAT DEMAND CHECKING VOLTAGE AT GAS VALVE 24VAC DURING IGNITION TRIALS GAS VALVE 3 LOW VOLTAGE TERMINAL STRIP WITH 3 AMP FUSE LOCATED...

Page 62: ...C NO NO YES YES DOES UNIT OPERATE CHECK 1 UNIT POWER 2 INTERLOCK SWITCH 3 TRANSFORMER 4 LIMIT SWITCH END OF TEST REPLACE THE VSP2 1 HEATING MODE NO YES YES YES AFTER THE SELECTED TIME DOES BLOWER TURN OFF PLACE HTG BLOWER JUMPER IN POSITION 1 R AND W1 REMAIN JUMPERED 1 CHECK UNIT WIRING AND IF CORRECT REPLACE VSP2 1 PLACE HTG BLOWER JUMPER IN POSITION 2 PLACE JUMPER ACROSS R AND W1 WAIT 75 SECOND ...

Page 63: ...NIT POWER 2 INTERLOCK SWITCH 3 TRANSFORMER 4 TRANSFORMER FUSE 5 UNIT WIRING IS 24VAC ACROSS J73 PIN 7 AND 1 OF VSP1 NO PRIMARY LIMIT S10 IS NC ALLOW UNIT TO COOL IF LIMIT REMAINS OPEN REPLACE LIMIT YES IS 24VAC ACROSS J73 PIN 3 AND 1 OF VSP1 NO REPLACE VSP1 YES NO CHECK WIRING BETWEEN TB1 AND VSP1 REPAIR IF NECESSARY YES IS 24VAC ACROSS J73 PIN 10 AND 1 OF VSP1 NO REPLACE VSP1 YES IS BLOWER ON LOW...

Page 64: ...S BLOWER TURN OFF IN ADDITION TO R AND W1 JUMPER HB AND W2 REMOVE HB AND W2 JUMPER DS3 DS2 DS1 L1 ACC YES NO DOES BLOWER SHIFT TO HIGH HEAT SPEED AND ARE DS1 AND DS2 LIT NO DOES BLOWER SHIFT TO HIGH HEAT SPEED AND ARE DS1 AND DS2 LIT DS3 DS2 DS1 CHECK UNIT WIRING AND IF CORRECT REPLACE THE VSP1 YES 1 J73 1 3 6 9 12 J73 V BLOWER AND VSP1 BLOWER CONTROL BOARD HEATING MODE CHECKOUT contd START HERE 1...

Page 65: ...UNIT OPERATE YES NO YES CHECK OUT ELECTRONICALLY CONTROLLED BLOWER MOTOR AND VSP1 SEE SECTION VIII NEW UNIT START UP IS 24VAC ACROSS R AND C IS 24VAC ACROSS J73 PIN 8 AND 1 OF VSP1 NO CHECK 1 UNIT POWER 2 INTERLOCK SWITCH 3 TRANSFORMER 4 TRANSFORMER FUSE 5 UNIT WIRING IS 24VAC ACROSS J73 PIN 7 AND 1 OF VSP1 NO PRIMARY LIMIT S10 IS NC ALLOW UNIT TO COOL IF LIMIT REMAINS OPEN REPLACE LIMIT YES IS 24...

Page 66: ...WER RUN REPLACE PURGE BLOWER REPLACE PRIMARY CONTROL CHECKOUT WIRING CONNECTIONS REPAIR IS DIFFERENTIAL PRESSURE SWITCH CUTTING OUT IF NO BLOCKAGE EXISTS REPLACE DIFFERENTIAL PRESSURE SWITCH 3 REPLACE SENSOR IF CRACKED 2 ARE CRACKS PRESENT IN PORCELAIN 1 WAS PLUG TIGHT WHEN REMOVED IS GAS VALVE ACTUALLY OPENING DETERMINE BY CHECKING FOR MANIFOLD PRESSURE DURING TRIALS FOR IGNITION REPLACE GAS VALV...

Page 67: ...EN 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 ...

Page 68: ...ST 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 RECIRCULATION CHECKS ARE LIMITS CUTTING OUT UNIT CHECK FOR OPEN LIMIT IMMEDIATELY FOLLOWING UNIT CUTOUT SHUT OFF POWER AND MAKE OHM METER CHECK NO IS GAS PRESSURE LOW CHECK FOR INTERMITTENT LOW GAS PRESSURE MONITOR LOW GAS PRESSURE NO YES CORRECT GAS PRESSURE IS EXHAUS...

Page 69: ...Typical G21Q Diagram Page 69 VIII WIRING DIAGRAMS AND SEQUENCE OF OPERATION 1 2 3 4 5 6 7 8 10 9 11 12 13 14 15 16 17 18 20 19 21 22 23 24 25 26 27 28 30 29 9 model shown ...

Page 70: ...ignition is sensed or after 8 0 seconds if ignition is not sensed Early GC 3 in later versions and G891 spark for a full 8 sec onds even if ignition is sensed 9 Combustion air blower B6 is de energized 5 seconds after ignition is sensed or after 8 0 seconds if ignition is not sensed Early GC 3 in later versions and G891 the combustion air blower B6 is de energized after 8 seconds 10 After the adju...

Page 71: ...TYPICAL GSR21Q DIAGRAM 11 MODEL SHOWN Page 71 1 2 3 4 5 6 7 8 10 9 11 12 13 14 15 16 17 18 20 19 21 22 23 24 25 26 28 30 29 ...

Page 72: ...nition is sensed or after 8 0 seconds if ignition is not sensed Early GC 3 in later versions and G891 the combustion air blower B6 is de ener gized after 8 seconds 10 After the adjustable time of 30 60 seconds of successful ignition A28 energizes K36 11 K36 1 N O closes energizing the blower B3 on heating speed and ACC terminal of TB2 is energized End of Heating Demand 12 Heating demand is satisfi...

Page 73: ...G21V 1 2 3 4 5 6 7 8 10 9 11 12 14 15 16 17 20 21 22 23 24 25 26 27 28 19 Page 73 29 30 31 32 13 ...

Page 74: ...e modulation control set point modulation limit S78 closes and signal to VSP2 is remade If there is still a call for heat unit will attempt ignition and operate until S78 cycles again Heating Single Stage Heating Blower Jumper in Position 1 APPLICATIONS WITH A SINGLE STAGE THERMOSTAT 14 The thermostat calls for heat W1 Ignition is established See steps 3 8 15 Internal circuitry of the VSP2 forces ...

Page 75: ...GSR21V Page 75 1 2 3 4 5 6 8 10 9 11 12 14 15 16 17 20 19 21 22 23 24 25 26 27 28 24 29 30 31 32 7 13 ...

Page 76: ...elow the modulation control set point modulation limit S78 closes and signal to VSP2 is remade If there is still a call for heat unit will attempt ignition and operate until S78 cycles again Heating Single Stage Heating Blower jumper in position 1 APPLICATIONS WITH A SINGLE STAGE THERMOSTAT 14 The thermostat calls for heat W1 Ignition is established See steps 3 8 15 Internal circuitry of the VSP2 ...

Page 77: ...G21Q with GC3 Ignition Control 1 2 3 4 5 6 7 8 10 9 11 12 13 14 15 16 17 18 20 19 21 22 23 24 25 26 27 28 30 29 Page 77 ...

Page 78: ...7 Fan timing control A28 is energized by gas valve GV1 8 Spark stops 5 seconds after ignition is sensed or after 8 0 seconds if ignition is not sensed 9 Combustionair blower B6 is de energized 5 seconds after ignition is sensed or after 8 0 seconds if ignition is not sensed 10 After 45 seconds of successful ignition A28 energizes K36 11 K36 1 N O closes energizing the blower B3 on heating speed an...

Page 79: ...G21Q with GC1 Ignition Control 1 2 3 4 5 6 7 8 10 9 11 12 13 14 15 16 17 18 20 19 21 22 23 24 25 26 28 30 29 Page 79 ...

Page 80: ...e ignition attempt 10 After 45 seconds of successful ignition A28 energizes K36 11 K36 1 N O closes energizing the blower B3 on heating speed and ACC terminal of TB2 is ener gized End of Heating Demand 12 Heating demand is satisfied 13 Ignition control A3 is de energized 14 Gas valve GV1 closes Pulse cycle stops 15 Combustion air blower is energized for 30 2 seconds post purge by ignition control ...

Page 81: ...GSR21Q with GC3 Ignition Control 1 2 3 4 5 6 7 8 10 9 11 12 13 14 15 16 17 18 20 19 21 22 23 24 25 26 28 30 29 Page 81 ...

Page 82: ... sensed or after 8 0 seconds if ignition is not sensed 10 After 45 seconds of successful ignition A28 energizes K36 11 K36 1 N O closes energizing the blower B3 on heating speed and ACC terminal of TB2 is ener gized End of Heating Demand 12 Heating demand is satisfied 13 Ignition control A3 is de energized 14 Gas valve GV1 closes Pulse cycle stops 15 Combustion air blower B6 is energized for 30 5 ...

Page 83: ...GSR21Q with GC1 Ignition Control 1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 18 20 19 21 22 23 24 25 27 28 29 8 9 Page 83 ...

Page 84: ...ining time of the ignition attempt 9 After 45 seconds of successful ignition A28 energizes K36 10 K36 1 N O closes energizing the blower B3 on heating speed and ACC terminal of TB2 is ener gized End of Heating Demand 11 Heating demand is satisfied 12 Ignition control A3 is de energized 13 Gas valve GV1 closes Pulse cycle stops 14 Combustion air blower B6 is energized for 30 2 seconds post purge by...

Page 85: ...G21V with GC1 Ignition Control 1 2 3 4 5 6 10 9 11 12 13 14 15 16 17 18 20 21 22 23 24 25 26 27 28 29 8 7 Page 85 ...

Page 86: ...blower to operate on low speed heat cool tap reducing heat ex changer temperature 14 When heat exchanger temperature falls below the modulation control set point modulation limit S78 closes and signal to VSP1 is remade If there is still a call for heat unit will attempt ignition and operate until S78 cycles again Heating Single Stage HB Jumpered to W2 APPLICATIONS WITH A SINGLE STAGE THERMOSTAT 15...

Page 87: ...G21V with GC3 Ignition Control 1 2 3 4 5 6 7 8 10 9 11 12 13 14 15 16 17 20 21 22 23 24 25 26 27 28 19 Page 87 ...

Page 88: ... operate on low speed heat cool tap reducing heat ex changer temperature 13 When heat exchanger temperature falls below the modulation control set point modulation limit S78 closes and signal to VSP1 is remade If there is still a call for heat unit will attempt ignition and operate until S78 cycles again Heating Single Stage HB Jumpered to W2 APPLICATIONS WITH A SINGLE STAGE THERMOSTAT 14 The ther...

Page 89: ...GSR21V with GC1 Ignition Control 1 2 3 4 5 6 7 8 10 9 11 12 13 14 15 16 17 20 19 21 22 23 24 25 26 27 28 29 Page 89 ...

Page 90: ...ces blower to operate on low speed heat cool tap reducing heat ex changer temperature 14 When heat exchanger temperature falls below the modulation control set point modulation limit S78 closes and signal to VSP1 is remade If there is still a call for heat unit will attempt ignition and operate until S78 cycles again Heating Single Stage HB Jumpered to W2 APPLICATIONS WITH A SINGLE STAGE THERMOSTA...

Page 91: ...GSR21V with GC3 Ignition Control 1 2 3 4 5 6 7 8 10 9 11 12 13 14 15 16 17 20 19 21 22 23 24 25 26 27 28 24 Page 91 ...

Page 92: ...r to operate on low speed heat cool tap reducing heat ex changer temperature 13 When heat exchanger temperature falls below the modulation control set point modulation limit S78 closes and signal to VSP1 is remade If there is still a call for heat unit will attempt ignition and operate until S78 cycles again Heating Single Stage HB Jumpered to W2 APPLICATIONS WITH A SINGLE STAGE THERMOSTAT 14 The ...

Page 93: ...g Heating Blower Jumper MUST BE in position 2 Blower operates on PWM signal generated by Har mony Harmony overrides blower speed taps Blower speed varies according to zone demand TABLE 18 WIRING CONNECTIONS W1 W2 R G Y1 Y2 DS NM W1 W2 R G Y1 Y2 DS C NM W1 W2 R G Y1 Y2 DS C NM S1 THERMOSTAT TB1 TERMINAL STRIP S1 THERMOSTAT TB1 TERMINAL STRIP TB1 TERMINAL STRIP ZONE CONTROLLER A1 HARMONY FOR COOLING...

Page 94: ...r no CCB1 no Harmony DS to G CCB1 with Single Speed Compressor no Harmony Blower speed is controlled by the DC signal from CCB1 Blower operates on low speed heat cool tap during dehumidi fication Otherwise blower op erates on high speed cool tap during cooling cycle No Jumpers Blower operates on high speed cool tap during cooling W1 W2 R G Y1 Y2 DS C NM continued on following page C W1 W2 R G Y1 Y...

Page 95: ...s according to zone demand continued from previous page W1 W2 R G Y1 Y2 DS C NM CCB1 with Two Speed Compressor no Harmony Blower speed is controlled by the DC signal from CCB1 Blower operates on low speed heat cool tap during dehumidi fication Otherwise blower op erates on high speed cool tap during high speed compressor operation and low speed heat cool tap during low speed compressor operation N...

Page 96: ...se blower op erates on cooling tap during cooling cycle A20 HUMIDITY CONTROL S1 THERMOSTAT W Y R G C No Jumpers TB1 TERMINAL STRIP Additional Wiring Re quired inside Unit Refer to EBR1 Blower Relay Kit Installation Instructions Additional Wiring Re quired inside Unit Refer to EBR1 Blower Relay Kit Installation Instructions Blower operates on a lower speed tap during dehumidifi cation Otherwise blo...

Page 97: ... S78 will cycle the unit Blower operates on the high speed heat tap during second stage heating Modula tion control S78 may not cycle the unit Harmony Heating No Jumpers Blower operates on PWM signal generated by Har mony Harmony overrides blower speed taps Blower speed varies according to zone demand TABLE 21 WIRING CONNECTIONS W1 W2 R G Y1 Y2 DS HB W1 W2 R G Y1 Y2 DS C HB W1 W2 R G Y1 Y2 DS C HB...

Page 98: ... no CCB1 no Har mony DS to G CCB1 with Single Speed Compressor no Harmony Blower speed is controlled by the DC signal from CCB1 Blower operates on low speed heat cool tap during dehumidi fication Otherwise blower op erates on high speed cool tap during cooling cycle No Jumpers Blower operates on high speed cool tap during cool ing W1 W2 R G Y1 Y2 DS C HB continued on following page C W1 W2 R G Y1 ...

Page 99: ...cording to zone de mand continued from previous page W1 W2 R G Y1 Y2 DS C HB CCB1 with Two Speed Compressor no Har mony Blower speed is controlled by the DC signal from CCB1 Blower operates on low speed heat cool tap during dehumidi fication Otherwise blower op erates on high speed cool tap during high speed compressor operation and low speed heat cool tap during low speed compressor operation No ...

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