Checking Flame Sensor - Goodman GMEC96 Service Instructions Manual

SERVICING
CAUTION - 120V
ST1
K11
K2 K1
K3
R92
Q3
Q2
W39
W35
Q72
W3
Q6
R201
R202
R200
E35
R586
FLAME
R50
R588
CURRENT
W15
R39 E36
W16
R40
W33
W1
W19
R49
W10
C14
R204
GL1
R35
W46
M2
W7
R566
Q9
R578
S1
E12
R568
1
2 U3
R580
3
R557
4
ON
OFF
R76
W40
R118
R570
S2
1
R82
R581
2 W52
R562
3
R38
OFF ON
R563
R71
R584
R115
Q13
W49
DS1
W2
Q11
R29
R564
R3
R573
R4
R553
SW3
R15
R10
Yl0
Y W1 W2 R
R
W20
W37
R27
ST3
R130
R11
R13
PCBBF133 Control Board
4. After the ignitor warmup time, begin checking for 24
volts to the gas valve. Voltage will be present for four
seconds only if proof of flame has been established.
5. If proof of flame was established voltage will be provided
to the air circulation blower following the heat on delay
period.
S-314 CHECKING FLAME SENSOR
A flame sensing device is used in conjunction with the igni-
tion control module to prove combustion. If proof of flame is
not present the control will de-energize the gas valve and
"retry" for ignition or lockout.
56
NEUTRALS
ST5
ST2
W18
K10
Q71
K6
Q7
R60
Q5
W34
W11
R58
Q70
C60
W44
C15
W31
R73
W53
R78
R74
Q60
R79
W12
W13
R81 W30
R61
K5
R85
R77
W29
Q10
K9
Q4
Q14
R780
ST6
R59
W32
R70
R53
R524
R63
R41
R75
R87
R31
R9
RV3
G C TWIN
R119
RV4
W51
R91
C13
E39
CR13
W24
W36 W14
R18
R65
W22
R21
R17
ST4
R12
F1
R33
R16
R2
R44 R54
E26 W4
HIGH VOLTAGE
D ALL
ISCONNECT
INSTALLING THIS UNIT.
F
BE PRESENT. AILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
Flame current can be measured in two ways:
1. Putting a D.C. microamp meter in series with the
E40
K4
flame rod
2. Putting a D.C. volt meter across the two solder pads
in the flame current section of the control board.
1 D.C. volt = 1 microamp.
C11
Flame Current
Solder Pads
E22
E27
L
INE VOLTAGE NOW PRESENT
3. As soon as flame is established a micro-amp reading
should be evident once proof of flame (micro-amp read-
ing) is established, the hot surface ignitor will be de-
energized.
4. The Integrated Ignition controls will have 1 to 4 micro-
amps. If the micro-amp reading is less than the mini-
mum specified, check for high resistance wiring con-
nections, sensor to burner gap, dirty flame sensor, or
poor grounding.
5. If absolutely no reading, check for continuity on all com-
ponents and if good - replace ignition control module.
NOTE: Contaminated fuel or combustion air can create a
nearly invisible coating on the flame sensor. This coating
works as an insulator causing a loss in the flame sense
signal. If this situation occurs the flame sensor must be
cleaned with steel wool.
WARNING
POWER BEFORE SERVICING OR
M
ULTIPLE POWER SOURCES MAY
WARNING