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

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Transducer Troubleshooting — The electronic control<br />

uses 2 suction pressure transducers to measure the suction<br />

pressure of circuits A <strong>and</strong> B. The pressure/voltage characteristics<br />

of these transducers are in shown in Tables 80 <strong>and</strong> 81. The<br />

accuracy of these transducers can be verified by connecting an<br />

accurate pressure gage to the second refrigerant port in the<br />

suction line.<br />

Forcing Inputs <strong>and</strong> Outputs — Many of variables<br />

may be forced both from the CCN <strong>and</strong> directly at the local<br />

display. This can be useful during diagnostic testing <strong>and</strong> also<br />

during operation, typically as part of an advanced third party<br />

control scheme. Please see Appendix A <strong>and</strong> B.<br />

NOTE: In the case of a power reset, any force levels in effect<br />

at the time of the power reset will be cleared.<br />

CONTROL LEVEL FORCING — If any of the following<br />

points are forced with a priority level of 7 (consult CCN literature<br />

for a description of priority levels), the software clears the<br />

force from the point if it has not been written to or forced again<br />

within the timeout periods defined below:<br />

Table 72 — Humidi-MiZer <strong>Service</strong> Analysis (cont)<br />

PROBLEM CAUSE REMEDY<br />

Unit Initiates a Humidi-MiZer<br />

Dehumidification Mode, but<br />

Supply Air Temperature is<br />

Overheating/Overcooling the<br />

Space<br />

Low Sensible Capacity in<br />

Normal Cooling Mode<br />

Modulating Valves Not<br />

Functioning Properly<br />

Supply air setpoint for cooling is too<br />

high/low<br />

Evaporator discharge temperature<br />

(CCT) or Supply air temperature (SAT)<br />

thermistor is reading incorrectly.<br />

Valve controlling gas bypass around<br />

the condenser is not functioning<br />

properly<br />

Valve controlling refrigerant flow to the<br />

condenser is not functioning properly<br />

Modulating valves are not calibrated<br />

properly<br />

Unit control software indicates a<br />

Humidi-MiZer Reheat Mode, but the<br />

3-way valve is not functioning properly<br />

Unit is not sized to meet the load at the<br />

current entering air <strong>and</strong> outdoor<br />

conditions.<br />

TemperaturesAIR.TOAT Outside Air Temperature 30 minutes<br />

TemperaturesAIR.TRAT Return Air Temperature 3 minutes<br />

TemperaturesAIR.TSPT Space Temperature 3 minutes<br />

InputsRSETSP.RS Static Pressure Reset 30 minutes<br />

InputsREL.HOA.RH Outside Air Relative Humidity 30 minutes<br />

InputsAIR.QOAQ Outside Air Quality 30 minutes<br />

93<br />

Check the unit supply air set point for cooling operation. This is the<br />

temperature that the valves will modulate to meet during a dehumidification<br />

mode.<br />

See "Thermistor Troubleshooting" on page 91<br />

Check if SAT thermistor is in a location that is measuring stratified<br />

air<br />

See "Modulating Valves Not Functioning Properly"<br />

See "Modulating Valves Not Functioning Properly"<br />

See "Modulating Valves Not Functioning Properly"<br />

See "3-Way Valve Malfunction"<br />

Check product data tables or ECAT for rated capacity at current<br />

entering air <strong>and</strong> outdoor conditions.<br />

Valve controlling gas bypass around See "Modulating Valves Not Functioning Properly"<br />

the condenser is stuck in an open position<br />

or leaking<br />

Valve controlling refrigerant flow to the See "Modulating Valves Not Functioning Properly"<br />

condenser is stuck in a position less<br />

than 100% open<br />

General cooling mode problem See "Cooling Troubleshooting," Table 71.<br />

Faulty wire connections Check that the valve wiring is properly connected from the valve,<br />

entering the control box <strong>and</strong> at the EXV board<br />

EXV board malfunction Check alarm history for A169 (Expansion Valve Control Board<br />

Comm Failure)<br />

Valve is stuck open/closed Use <strong>Service</strong> Test to manually manipulate the valve position <strong>and</strong><br />

confirm supply air temperature changes during operation.<br />

Run valve calibration through <strong>Service</strong> Test<br />

Check valve motor for open or short circuited windings. Shut down<br />

power to the unit <strong>and</strong> connect Ohmmeter probes across the black<br />

<strong>and</strong> white terminals. Resistance should measure 75 Ohms ±10%.<br />

Next, connect Ohmmeter probes across the red <strong>and</strong> green terminals.<br />

Resistance should measure 75 Ohms ±10%. The meter<br />

should not show an "open" or a "short" when a winding leg is measured.<br />

If either occurs, replace the valve.<br />

Valve is not calibrated properly Run valve calibration through <strong>Service</strong> Test<br />

Run Status Menu — The Run Status menu provides the<br />

user important information about the unit. The Run Status table<br />

can be used to troubleshoot problems <strong>and</strong> to help determine<br />

how <strong>and</strong> why the unit is operating.<br />

AUTO VIEW OF RUN STATUS — The Auto View of Run<br />

Status display table provides the most important unit information.<br />

The HVAC Mode (Run StatusVIEW HVAC) informs<br />

the user what HVAC mode the unit is currently in. Refer<br />

to the Modes section on page 40 for information on HVAC<br />

modes. The occupied status, unit temperatures, unit set points,<br />

<strong>and</strong> stage information can also be shown. See Table 82.<br />

Run StatusVIEWHVAC — Displays the current HVAC<br />

Mode(s) by name. HVAC Modes include:<br />

OFF VENT HIGH HEAT<br />

STARTING UP HIGH COOL FIRE SHUT DOWN<br />

SHUTTING DOWN LOW COOL PRESSURIZATION<br />

DISABLED UNOCC FREE COOL EVACUATION<br />

SOFTSTOP REQUEST TEMPERING HICOOL SMOKE PURGE<br />

REM SW DISABLE TEMPERING LOCOOLDEHUMIDIFICATION<br />

COMP STUCK ON TEMPERING VENT RE-HEAT<br />

TEST LOW HEAT<br />

Run StatusVIEWOCC — Displays the current occupancy<br />

status of the control.<br />

Run StatusVIEWMAT — Displays the current value for<br />

mixed-air temperature. This value is calculated based on<br />

return-air <strong>and</strong> outside-air temperatures <strong>and</strong> economizer damper<br />

position.

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