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Cooling Failure
1. Cooling and heating set point (slide pot) on the zone sensor
has failed. Refer to the “Zone Sensor Test Procedure” sec-
tion.
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 ap-
ply 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 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 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, pur-
chase a BAYSENS010B ZSM and connect wires with alliga-
tor clamps to terminals 6 through 10. Connected each re-
spective 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 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” selec-
tion switch at the zone sensor to the “Off” position. After ap-
proximately 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 turn-
ing the disconnect switch “Off” and then “On”.
Lockouts can be cleared through the building management
system. Refer to the building management system instruc-
tions for more information.
Zone Temperature Sensor (ZTS) Service Indicator
The ZSM SERVICE LED is a generic indicator, that will sig-
nal the closing of a Normally Open switch at any time, pro-
viding 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 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 immedi-
ately after resetting the switch (to the Normally Open posi-
tion), 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.
Trouble Shooting
Содержание YHC033A
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