Controls, Start-Up, Operation, Service and ... - Climayoreo

Transducer Troubleshooting — The electronic control
uses 2 suction pressure transducers to measure the suction
pressure of circuits A and B. The pressure/voltage characteristics
of these transducers are in shown in Tables 80 and 81. The
accuracy of these transducers can be verified by connecting an
accurate pressure gage to the second refrigerant port in the
suction line.
Forcing Inputs and Outputs — Many of variables
may be forced both from the CCN and directly at the local
display. This can be useful during diagnostic testing and also
during operation, typically as part of an advanced third party
control scheme. Please see Appendix A and B.
NOTE: In the case of a power reset, any force levels in effect
at the time of the power reset will be cleared.
CONTROL LEVEL FORCING — If any of the following
points are forced with a priority level of 7 (consult CCN literature
for a description of priority levels), the software clears the
force from the point if it has not been written to or forced again
within the timeout periods defined below:
Table 72 — Humidi-MiZer Service Analysis (cont)
PROBLEM CAUSE REMEDY
Unit Initiates a Humidi-MiZer
Dehumidification Mode, but
Supply Air Temperature is
Overheating/Overcooling the
Space
Low Sensible Capacity in
Normal Cooling Mode
Modulating Valves Not
Functioning Properly
Supply air setpoint for cooling is too
high/low
Evaporator discharge temperature
(CCT) or Supply air temperature (SAT)
thermistor is reading incorrectly.
Valve controlling gas bypass around
the condenser is not functioning
properly
Valve controlling refrigerant flow to the
condenser is not functioning properly
Modulating valves are not calibrated
properly
Unit control software indicates a
Humidi-MiZer Reheat Mode, but the
3-way valve is not functioning properly
Unit is not sized to meet the load at the
current entering air and outdoor
conditions.
TemperaturesAIR.TOAT Outside Air Temperature 30 minutes
TemperaturesAIR.TRAT Return Air Temperature 3 minutes
TemperaturesAIR.TSPT Space Temperature 3 minutes
InputsRSETSP.RS Static Pressure Reset 30 minutes
InputsREL.HOA.RH Outside Air Relative Humidity 30 minutes
InputsAIR.QOAQ Outside Air Quality 30 minutes
93
Check the unit supply air set point for cooling operation. This is the
temperature that the valves will modulate to meet during a dehumidification
mode.
See "Thermistor Troubleshooting" on page 91
Check if SAT thermistor is in a location that is measuring stratified
air
See "Modulating Valves Not Functioning Properly"
See "Modulating Valves Not Functioning Properly"
See "Modulating Valves Not Functioning Properly"
See "3-Way Valve Malfunction"
Check product data tables or ECAT for rated capacity at current
entering air and outdoor conditions.
Valve controlling gas bypass around See "Modulating Valves Not Functioning Properly"
the condenser is stuck in an open position
or leaking
Valve controlling refrigerant flow to the See "Modulating Valves Not Functioning Properly"
condenser is stuck in a position less
than 100% open
General cooling mode problem See "Cooling Troubleshooting," Table 71.
Faulty wire connections Check that the valve wiring is properly connected from the valve,
entering the control box and at the EXV board
EXV board malfunction Check alarm history for A169 (Expansion Valve Control Board
Comm Failure)
Valve is stuck open/closed Use Service Test to manually manipulate the valve position and
confirm supply air temperature changes during operation.
Run valve calibration through Service Test
Check valve motor for open or short circuited windings. Shut down
power to the unit and connect Ohmmeter probes across the black
and white terminals. Resistance should measure 75 Ohms ±10%.
Next, connect Ohmmeter probes across the red and green terminals.
Resistance should measure 75 Ohms ±10%. The meter
should not show an "open" or a "short" when a winding leg is measured.
If either occurs, replace the valve.
Valve is not calibrated properly Run valve calibration through Service Test
Run Status Menu — The Run Status menu provides the
user important information about the unit. The Run Status table
can be used to troubleshoot problems and to help determine
how and why the unit is operating.
AUTO VIEW OF RUN STATUS — The Auto View of Run
Status display table provides the most important unit information.
The HVAC Mode (Run StatusVIEW HVAC) informs
the user what HVAC mode the unit is currently in. Refer
to the Modes section on page 40 for information on HVAC
modes. The occupied status, unit temperatures, unit set points,
and stage information can also be shown. See Table 82.
Run StatusVIEWHVAC — Displays the current HVAC
Mode(s) by name. HVAC Modes include:
OFF VENT HIGH HEAT
STARTING UP HIGH COOL FIRE SHUT DOWN
SHUTTING DOWN LOW COOL PRESSURIZATION
DISABLED UNOCC FREE COOL EVACUATION
SOFTSTOP REQUEST TEMPERING HICOOL SMOKE PURGE
REM SW DISABLE TEMPERING LOCOOLDEHUMIDIFICATION
COMP STUCK ON TEMPERING VENT RE-HEAT
TEST LOW HEAT
Run StatusVIEWOCC — Displays the current occupancy
status of the control.
Run StatusVIEWMAT — Displays the current value for
mixed-air temperature. This value is calculated based on
return-air and outside-air temperatures and economizer damper
position.