102777-YIM-E-0206
Unitary Products Group
95
TROUBLESHOOTING A MILLENNIUM SIM-
PLICITY CONTROL
STATUS LED CHART
The Status LED mounted on the controller PC board will flash
specified flash patterns to indicate rooftop unit status. See
Table 47.
Flash Times:
•
Off:
The power is Off, or the control has failed
•
On 250ms Off 250ms:
The Control is operating but an
Alarm is active.
•
(The Number of the Alarm will be displayed on the char-
acter display.)
•
On one second, Off one second:
This will be the "Heat
Beat"; The Control is operating normally with no Alarms.
•
On Steady:
The Control has Failed
•
Two flashes On, then two seconds Off:
The Control is
waiting for an ASCD Timer to finish.
FAILURE MODES AND DEFAULT OPERATION
ERROR HISTORIES
Error data storage: The control will store the latest five errors
in a FIFO manner in EEPROM, for later display. It will store
status information ("active" vs. "inactive") for all error types to
provide for situations when an error snapshot is triggered by
multiple errors occurring at the same time. As the control col-
lects errors, it will overwrite the oldest error after the history
buffer becomes full.
Errors that are entered into the error history buffer:
•
Compressor locked out on safety chain trip
•
Supply fan failure
•
Heating SAT failure
•
Cooling SAT failure
•
SAT,RAT,OAT,IAQ, ST, or RH failure
•
Duct static or Bldg. Pressure sensor failure
•
Dirty Filter alarm
•
High duct static alarm
•
Hot Water Coil Freeze alarm
•
External alarm input
•
Bad Air Proving Switch
SENSOR FAILURES AND DEFAULT OPERATION
A failure of SAT RAT, OAT, IAQ, Space Temperature, or an
outside or return air Relative Humidity sensor will generate a
common error. A failure of the Duct Static or Building Pres-
sure sensor will generate another common error. The errors
will be indicated by a Status LED (see Status LED Chart ear-
lier in this chapter). The errors will be written to the Error His-
tory Buffer. In networked application, the error flag will be
readable by the network. The error indication of a sensor fail-
ure will continue until the problem is corrected and will auto-
matically terminate when the sensor is again detected as
reliable. If the unit is shut down as a result of a sensor failure,
the alarm must be reset (after the sensor problem has been
corrected) by resetting the controller (power cycle, or reset
command issued by the Palm Pilot Configuration Tool).
SAT SENSOR
CV operation:
If the SAT sensor fails, the Economizer,
excessive SAT control and predicted SAT drop checking will
be disabled. The Control will then continue a "limp along"
operation under zone thermostat, or zone sensor control. For
VAV operation the unit will be shut down.
RAT SENSOR
If the RAT sensor fails, Morning Warm Up mode and VAV
Occupied Heating are disabled. For Economizer Loading
function, the control will default to estimated RAT of 75
°
F (for
this function only).
OAT SENSOR
Units without Economizer:
If there is no Economizer, the
control will lockout Cooling on an OAT sensor failure. This is
because the controller can not determine when cooling needs
to be locked out at low OAT to prevent damage to compres-
sors. Heating operation will continue normally.
Units with Economizer:
All Economizer Operation will be
disabled. This is because OAT sensor is the most essential
sensor in determining availability of free cooling. Even if the
unit is equipped with Outside RH sensor and controller could
calculate Outdoor Enthalpy, the OAT sensor is still essential
in that calculation. The Economizer will only modulate to the
Minimum Position when the Fan is operating and the control
is Occupied.
OUTSIDE AIR RELATIVE HUMIDITY SENSOR
If the OAH sensor fails, the control will only use the OAT sen-
sor to decide if Free Cooling is available. The control will self-
configure to Outside Temperature Method (see also Econo-
mizer Operation section earlier in this document).
RETURN AIR RELATIVE HUMIDITY SENSOR
The control will self-configure to Outside Enthalpy Operation.
TABLE 47: STATUS LED CHART
Flash Codes
Decription
On Steady
Control Failure
1 Flash
(Not Applicable)
2 Flashes
Control waiting ASCD
OFF
No Power or Control Failure
Summary of Contents for MILLENNIUM Y22
Page 47: ...102777 YIM E 0206 Unitary Products Group 47 FIGURE 20 ALTITUDE TEMPERATURE CONVERSION FACTOR ...
Page 50: ...102777 YIM E 0206 50 Unitary Products Group FIGURE 21 FAN PERFORMANCE 25 TON ...
Page 53: ...102777 YIM E 0206 Unitary Products Group 53 FIGURE 22 FAN PERFORMANCE 30 TON ...
Page 56: ...102777 YIM E 0206 56 Unitary Products Group FIGURE 23 FAN PERFORMANCE 40 TON ...
Page 126: ...102777 YIM E 0206 126 Unitary Products Group FIGURE 52 TYPICAL CONTROL WIRING ...
Page 127: ...102777 YIM E 0206 Unitary Products Group 127 FIGURE 53 LEGEND ...
Page 128: ...102777 YIM E 0206 128 Unitary Products Group FIGURE 54 TYPICAL 25 TON POWER WIRING ...
Page 129: ...102777 YIM E 0206 Unitary Products Group 129 FIGURE 55 TYPICAL 30 40 TON POWER WIRING ...
Page 130: ...102777 YIM E 0206 130 Unitary Products Group FIGURE 56 TYPICAL GAS HEAT WIRING ...
Page 134: ...102777 YIM E 0206 134 Unitary Products Group FIGURE 58 25 TON CHARGING CURVE ...
Page 139: ...102777 YIM E 0206 Unitary Products Group 139 ...
