SS-SVX10H-EN
49
Range = 100 to 900 Ohms approximate
H
He
ea
att S
SP
P = Terminals 2 and 5
Range = 100 to 900 Ohms approximate
Test 3 - System Mode and Fan Selection
The combined resistance of the M
MO
OD
DE
E selection switch
and the F
FA
AN
N selection switch can be measured
between terminals 2 and 4 on the Zone Sensor. The
possible switch combinations are listed in
with their corresponding resistance values.
Table 12.
Test 3 - system mode and fan selection
Resistance Valves(Ohms)
Zone Sensor Unit/Fan
Mode
Local Unit Mode
Local Fan Mode
2.32K
Off/Auto
Off
Auto
4.87K
Cool/Auto
Cool
Auto
7.68K
Auto/Auto
Auto
Auto
10.77K
Off/On
Off
On
13.32K
Cool/On
Cool
On
16.13K
Auto/On
Auto
On
19.48K
Heat/Auto
Heat
Auto
27.93K
Heat/On
Heat
On
35.0K
Emergency Heat/Auto
Emergency Heat
Auto
43.45K
Emergency Heat/On
Emergency Heat
On
Out of Range (Short)
INVALID/Short
Invalid (CV), Auto (VAV)
Invalid
Out of Range (Open)
INVALID/Open
Invalid (CV), Off (VAV)
Invalid
Test 4 - LED Indicator Test (SYS ON,
HEAT, & COOL)
W
WA
AR
RN
NIIN
NG
G
L
Liiv
ve
e E
Elle
ec
cttrriic
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all C
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affe
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on
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he
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ve
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cttrriic
ca
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om
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Method 1
Testing the LED using a meter with diode test function.
Test both forward and reverse bias. Forward bias
should measure a voltage drop of 1.5 to 2.5 volts,
depending on your meter. Reverse bias will show an
Over Load, or open circuit indication if LED is
functional.
Method 2
Testing the LED with an analog Ohmmeter. Connect
Ohmmeter across LED in one direction, then reverse
the leads for the opposite direction. The LED should
have at least 100 times more resistance in reverse
direction, as compared with the forward direction. If
high resistance in both directions, LED is open. If low in
both directions, LED is shorted.
Method 3
To test LED’s with ZSM connected to unit, test voltages
at LED terminals on ZSM. A measurement of 32 VDC,
across an unlit LED, means the LED has failed.
IIm
mp
po
orrtta
an
ntt:: Measurements should be made from LED
common (ZSM terminal 6 to respective LED
terminal).
Programmable & Digital Zone
Sensor Test
Testing Serial Communication Voltage
1.
Verify 24 VAC is present between terminals J6-14 &
J6-11.
