Method 2; Indicator; Clogged Filter Switch; Fan Failure Switch - Trane Axiom GWS Series Installation, Operation And Maintenance Manual

Method 2

To reset the system at the unit, cycle the unit power by
turning the disconnect switch "Off" and then "On".
Lockouts can be cleared through the building
management system. Refer to the building
management system instructions for more
information.

Zone Temperature Sensor (ZTS)

Service Indicator
The ZSM SERVICE LED is a generic indicator, that will
signal the closing of a Normally Open switch at any
time, providing the Indoor Motor (IDM) is operating.
This indicator is usually used to indicate a clogged
filter, or an air side fan failure.
The RTRM will ignore the closing of this Normally
Open switch for 2 (±1) minutes. This helps prevent
nuisance SERVICE LED indications. The exception is
the LED will flash 40 seconds after the fan is turned
"On" if the Fan Proving Switch is not made.

Clogged Filter Switch

This LED will remain lit the entire time that the
Normally Open switch is closed. The LED will be turned
off immediately after resetting the switch (to the
Normally Open position), or any time that the IDM is
turned "Off".
If the switch remains closed, and the IDM is turned
"On", the SERVICE LED will be turned "On" again after
the 2 (±1) minute ignore delay.
This LED being turned "On", will have no other affect
on unit operation. It is an indicator only.

Fan Failure Switch

When the "Fan Failure" switch is wired to the RTOM,
the LED will remain flashing the entire time the fan
proving switch is closed, indicating a fan failure, and it
will shut the unit operations down.

Condensate Overflow Switch

This input incorporates the condensate overflow switch
(COF) mounted on the drain pan and the ReliaTel™
options module (RTOM). When the condensate level
reaches the trip point for 6 continuous seconds, the
RTOM will shut down all unit function until the
overflow condition has cleared. The unit will return to
normal operation after 6 continuous seconds with the
COF in a non-tripped condition. If the condensate level
causes the unit to shut down more than 2 times in a 3
day period, the unit will be locked-out of operation. A
manual reset of the diagnostic system through the
zone sensor or Building Automation System (BAS) will
be required. Cycling unit power will also clear the fault.
WSHP-SVX015C-EN
Zone Temperature Sensor (ZTS)

Tests

N N o o t t e e : : These procedures are not for programmable or
digital models and are conducted with the Zone
Sensor Module electrically removed from the
system.
Test 1: Zone Temperature Thermistor
(ZTEMP)
This component is tested by measuring the resistance
between terminals 1 and 2 on the Zone Temperature
Sensor. Below are some typical indoor temperatures,
and corresponding resistive values.
Zone Temperature
50 F° 10.0 C°
55 F° 12.8 C°
60 F° 15.6 C°
65 F° 18.3 C°
70 F° 21.1 C°
75 F° 23.9 C°
80 F° 26.7 C°
85 F° 29.4 C°
90 F° 32.2 C°
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
setpoints.
Cool SP = Terminals 2 and 3
Range = 100 to 900 Ohms approximate
Heat SP = 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 Zone Sensor. The possible
switch combinations are listed on the following page
with their corresponding resistance values.
Test 4: LED Indicator Test, (SYS ON,
HEAT, COOL & SERVICE)
Method 1
Testing the LED using a meter with diode test function.
Test both forward and reverse bias. Forward bias
T T r r o o u u b b l l e e s s h h o o o o t t i i n n g g
Nominal Nominal
ZTEMP CSP or HSP
Resistance Resistance
19.9 K-Ohms 889 Ohms
17.47 K-Ohms 812 Ohms
15.3 K-Ohms 695 Ohms
13.49 K-Ohms 597 Ohms
11.9 K-Ohms 500 Ohms
10.50 K-Ohms 403 Ohms
9.3 K-Ohms 305 Ohms
8.25 K-Ohms 208 Ohms
7.3 K-Ohms 110 Ohms
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