Resetting Cooling And Ignition Lockouts; Zone Temperature Sensor (Zts) Service Indicator - American Standard YSC036A Installation, Operation And Maintenance Manual

Heating Failure
Verify Heat Failure by Ignition
Module (IGN) LED indicator:
OFF: No Power or Failure
ON: Normal
Slow Flash: Normal, Heat Call
Fast Flash: Error Code:
1 Flash: Communication Failure
2 Flashes: System Lockout
3 Flashes: Pressure Switch Fail
4 Flashes: TC01 or TC02 Open
5 Flashes: Flame w/o Gas Valve
6 Flashes: Flame Rollout Open
Cooling Failure
1. Cooling and heating set point
(slide pot) on the zone sensor
has failed. Refer to the "Zone
Sensor Test Procedure" 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 voltage between
the J1-1 & J3-2 terminals 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
46
Method 2
The second method for determining
system status is done by checking
voltage 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,
approximately 0.75 VDC
Test Mode = voltage alternates
between 32 VDC & 0.75 VDC
Heat Failure
Measure the voltage between
terminals J6-7 & J6-6.
Heat Operating = approximately 32
VDC
Heat Off = less than 1 VDC,
approximately 0.75 VDC
Heating Failure = voltage alternates
between 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,
approximately 0.75 VDC
Cooling Failure = voltage alternates
between 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,
approximately 0.75 VDC Fan Failure =
voltage alternates between 32 VDC &
0.75 VDC.
To use LED's for quick status
information 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.
Trouble Shooting
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 resetting 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
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.
RT-SVX21F-EN