RT-SVX31A-EN40
Cooling Failure
1. Cooling and heating set point (slide
pot) on the zone sensor has failed.
Refer to the “Zone Sensor Test Pro-
cedure” section.
2. Zone temperature thermistor ZTEMP
on ZTS failed. Refer to the “Zone
Sensor Test Procedure” section.
3. CC1 or CC2 24 VAC control circuit
has opened, check CC1 & CC2
coils, and any of the controls below
that apply to the unit (HPC1, HPC2).
4. LPC1 has opened during the 3
minute minimum “on time” during 4
consecutive compressor starts,
check LPC1 or LPC2 by testing volt-
age between the J1-1 & J3-2 termi-
nals on the RTRM and ground. If 24
VAC is present, the LPC’s has not
tripped. If no voltage is present,
LPC’s has tripped.
Service Failure
1. If the supply fan proving switch has
closed, the unit will not operate
(when connected to RTOM), check
the fan motor, belts, and proving
switch.
2. Clogged filter switch has closed,
check the filters.
Simultaneous Heat and Cool Failure
1. Emergency Stop is activated
Method 2
The second method for determining
system status is done by checking volt-
age readings at the RTRM (J6). The
system indication descriptions and the
approximate voltages are listed below.
System Failure
Measure the voltage between terminals
J6-9 & J6-6.
Normal Operation = approximately 32
VDC
System Failure = less than 1 VDC, ap-
proximately 0.75 VDC
Test Mode = voltage alternates be-
tween 32 VDC & 0.75 VDC
Trouble Shooting
Heat Failure
Measure the voltage between terminals
J6-7 & J6-6.
Heat Operating = approximately 32
VDC
Heat Off = less than 1 VDC, approxi-
mately 0.75 VDC
Heating Failure = voltage alternates be-
tween 32 VDC & 0.75 VDC
Cool Failure
Measure the voltage between terminals
J6-8 & J6-6.
Cool Operating = approximately 32
VDC
Cool Off = less than 1 VDC, approxi-
mately 0.75 VDC
Cooling Failure = voltage alternates be-
tween 32 VDC & 0.75 VDC
Service Failure
Measure the voltage between terminals
J6-10 & J6-6.
Clogged Filter = Approximately 32
VDC.
Normal = Less than 1 VDC, approxi-
mately 0.75 VDC Fan Failure = voltage
alternates between 32 VDC & 0.75
VDC.
To use LED’s for quick status informa-
tion at the unit, purchase a
BAYSENS010B ZSM and connect wires
with alligator clamps to terminals 6
through 10. Connected each respective
terminal wire (6 through 10) from the
Zone Sensor to the unit J6 terminals 6
through 10.
Note:
If the system is equipped with a
programmable zone sensor,
BAYSENS019B the LED indicators will
not function while the BAYSENS010A is
connected.
Resetting Cooling and Ignition
Lockouts
Cooling Failures and Ignition Lockouts
are reset in an identical manner.
Method 1 explains resetting the system
from the space; Method 2 explains re-
setting the system at the unit.
Note:
Before resetting Cooling Failures and
Ignition Lockouts check the Failure
Status Diagnostics by the methods
previously explained. Diagnostics will be
lost when the power to the unit is
disconnected.
Method 1
To reset the system from the space,
turn the “Mode” selection switch at the
zone sensor to the “Off” position. After
approximately 30 seconds, turn the
“Mode” selection switch to the desired
mode, i.e. Heat, Cool or Auto.
Method 2
To reset the system at the unit, cycle
the unit power by turning the discon-
nect switch “Off” and then “On”.
Lockouts can be cleared through the
building management system. Refer to
the building management system in-
structions 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, pro-
viding the Indoor Motor (IDM) is operat-
ing. This indicator is usually used to in-
dicate a clogged filter, or an air side fan
failure.
The RTRM will ignore the closing of this
Normally Open switch for 2 (±1) min-
utes. This helps prevent nuisance SER-
VICE 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 im-
mediately after resetting the switch (to
the Normally Open position), or any
time that the IDM is turned “Off”.
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