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RT-SVX34R-EN
Smoke Detector Switch
The LED will flash anytime that the N.O. Smoke
Detector input is closed and will be reset anytime that
the input is returned to its N.O. state. During an Active
Smoke Detector trip the unit will be shut down.
Fan Failure Switch
The LED will flash 40 seconds after the fan is turned
“On” if the Fan Proving Switch is not made. This LED
will remain flashing until the unit is reset by means
explained above. If the “Fan Failure” switch opens for
at least 40 seconds during fan operation (indicating a
fan failure) the unit will stop.
Condensate Overflow Switch
When the condensate overflow switch is closed, a drain
pan overflow condition is indicated and it will shut unit
operations down.
RTRM Zone Sensor Module (ZSM) Tests
NNoottee:: These procedures are not for programmable or
digital models and are conducted with the Zone
Sensor Module electrically removed from the
system.
Table 73. Zone Sensor Module (ZSM) terminal
identification (constant volume only)
Terminal #
Terminal I.
D. Terminal #
Terminal I.
D.
J6-1 ZTEMP J6-6 LED COMMON
J6-2
SIGNAL
COMMON
J6-7 HEAT LED
J6-3 CSP* J6-8 COOL LED
J6-4 MODE J6-9 SYS ON LED
J6-5 HSP J6-10 SERVICE LED
Test 1: Zone Temperature Thermistor (ZTEMP)
This component is tested by measuring the resistance
between terminals 1 and 2 on the Zone Temperature
Sensor. The following are some typical indoor
temperatures, and corresponding resistive values.
Table 74. Resistance values
Zone or Set
Point
Temperature
Nominal ZTEMP
Resistance
Nominal CSP or
HSP Resistance
50° F 19.9 K-Ohms 889 Ohms
55° F 17.47 K-Ohms 812 Ohms
60° F 15.3 K-Ohms 695 Ohms
65° F 13.49 K-Ohms 597 Ohms
70° F 11.9 K-Ohms 500 Ohms
75° F 10.50 K-Ohms 403 Ohms
80° F 9.3 K-Ohms 305 Ohms
Table 74. Resistance values (continued)
Zone or Set
Point
Temperature
Nominal ZTEMP
Resistance
Nominal CSP or
HSP Resistance
85° F 8.25 K-Ohms 208 Ohms
90° F 7.3 K-Ohms 110 Ohms
Test 2: Cooling Set Point (CSP) and Heating Set
Point (HSP)
The resistance of these potentiometers are measured
between the following ZSM terminals. Refer to the
chart above for approximate resistances at the given
set points.
CSP = Terminals 2 and 3
Range = 100 to 900 Ohms approximate
HSP = Terminals 2 and 5
Range = 100 to 900 Ohms approximate
Test 3: System Mode and Fan Selection
The combined resistance of the Mode selection switch
and the Fan selection switch can be measured between
terminals 2 and 4 on the ZSM. The possible switch
combinations are listed below with their corresponding
resistance values.
Table 75. Nominal resistance
VAV
System
Switch
CV System
Switch
CV Fan
Switch
Nominal
Resistance
OFF
OFF AUTO 2.3 K-Ohms
COOL AUTO 4.9 K-Ohms
AUTO
AUTO AUTO 7.7 K-Ohms
OFF ON 11.0 K-Ohms
COOL ON 13.0 K-Ohms
AUTO ON 16.0 K-Ohms
HEAT AUTO 19.0 K-Ohms
HEAT ON 28.0 K-Ohms
Test 4: LED Indicator Tests (SYS ON, HEAT, COOL
& SERVICE)
• MMeetthhoodd 11:: 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.
• MMeetthhoodd 22:: 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
DDiiaaggnnoossttiiccss
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