V" Blower And Vsp1 Blower Control Board Cooling Mode Checkout - Lennox G21Q3-40 Unit Information

V" BLOWER AND VSP1 BLOWER CONTROL BOARD COOLING MODE CHECKOUT

CHECK OUT ELECTRONICALLY CONTROLLED BLOWER MOTOR AND VSP1
YES
12 9 6
3
1
J73
TB2
ACC N
120VAC?
CHECK VOLTAGE ON TB2 FROM ACC TO N ON TERMINAL
BLOCK INSIDE CONTROL BOX−SHOULD READ "120" VOLTS AC
END OF COOLING TEST
WARNING
Disconnect thermostat wire to DS terminal before
performing any test on this page.
G
W1
W2
R
TB1 TERMINAL STRIP
START HERE
DOES UNIT OPERATE?
SEE SECTION VIII NEW UNIT START UP
IS 24VAC ACROSS J73
PIN 8 AND 1
OF VSP1?
IS 24VAC ACROSS J73
PIN 7 AND 1
OF VSP1?
IS 24VAC ACROSS J73
PIN 3 AND 1
OF VSP1?
IS 24VAC ACROSS R AND C ?
PLACE JUMPER ACROSS R AND G.
IS BLOWER ON LOW SPEED COOLING TAP
AND IS DS1 LIT?
IS THE ACCESSORY
RELAY PULLED IN?
IN ADDITION TO R AND G, JUMPER R AND DS.
YES IS BLOWER ON HIGH
SPEED COOLING TAP?
ARE DS1 AND DS3
Y1 Y2
DISCONNECT DS
DS
C
HB
NO
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
CHECK UNIT WIRING AND IF CORRECT
LIT?
VSP1
1
DS3 DS2 DS1
ACC
L1
Page 65
CHECK:
1−UNIT POWER
2−INTERLOCK SWITCH
3−TRANSFORMER
4−TRANSFORMER FUSE
5−UNIT WIRING
PRIMARY LIMIT S10 IS NC
ALLOW UNIT TO COOL
IF LIMIT REMAINS OPEN
REPLACE LIMIT
REPLACE VSP1
CHECK WIRING BETWEEN TB1 AND VSP1
REPAIR IF NECESSARY
DS3 DS2 DS1
CHECK UNIT WIRING AND IF CORRECT,
REPLACE VSP1.
CHECK UNIT WIRING FROM VSP1 TO TB2
AND IF CORRECT, REPLACE VSP1.
DS3 DS2 DS1
REPLACE THE VSP1.
1
J73
12
START
HERE
9 6
3
1
J73