Armstrong World Industries EHU-703, EHU-701 manual C04 High Limit Circuit, C05 Drain System Failure

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C04: HIGH LIMIT CIRCUIT:

When the humidity in the duct reaches the high limit stat set-point, the circuit will open and the microcontroller will de-energize the contactor. The diagnostic mode will display the message C04 and the fill solenoid is blocked.

C05: DRAIN SYSTEM FAILURE:

This routine checks for a failure to reduce current if the drain valve is energized for more than five seconds. If the actual current does not decrease when the microcontroller demands a drain cycle, the unit will go into a diagnostic routine. This routine will try twice to correct the drain system failure by cycling the drain valve rapidly. If the failure is not corrected, the unit will shut down. The tank off indicator will light, the numerical display will show C05 (the drain valve failure message), and the dry contact will close to activate the remote alarm.

Drain system failure can be due to a plugged drain valve, drain valve solenoid failure, scale buildup in the tank, or drain piping problems. Refer to the maintenance section of this manual for resolution of these problems.

C06: FILL SYSTEM FAILURE:

After start-up, if the fill valve is on and has been on for more than four minutes, the diagnostic routine will check the fill valve operation. If the actual amp signal is less than the current when the fill valve was opened, the unit will go into a diagnostic routine. If the problem cannot be corrected, a fill system failure will be triggered and the unit shut down. The three digit display will show C06 to indicate this condition, and the dry contact will close to activate the remote alarm.

Fill system failure can be due to excessive or insufficient inlet water pressure, a failed fill valve solenoid, a plugged fill valve failed open, or a backflow preventer. Refer to the maintenance section of this manual for resolution of these problems.

C07: OVERCURRENT FAILURE:

The overcurrent limit (OCL) is 20% above the nominal amp rating of the unit. When the actual current reaches the OCL, the microcontroller will de-energize the contactor and energize the drain valve for 15 seconds. Then the contactor will be re-energized to see if the drain valve has corrected the overcurrent condition. This procedure is repeated 5 times.

If the overcurrent still exists, an overcurrent failure indication of C07 is displayed, the unit is shut down, and the dry contact will close to activate the remote alarm. The unit will have to be manually reset and the overcurrent condition addressed by the maintenance personnel.

An overcurrent failure can result from the cold startup of a tank that was previously running at a high load, resulting in the tank water becoming too conductive for start-up. If this is suspected, manually drain the tank for 15-30 seconds, then try to restart the system. If the overcurrent failure repeats, the drain system could be partially plugged, or the tank may be in need of cleaning. Refer to the maintenance section of this manual for resolutions to these problems.

C08: MANUAL TANK SHUT-OFF:

The tank on/off button will de-energize the tank contactor. The tank off light and the diagnostics indicator will be on and the display will show the message C08. The unit will stay in this condition until the button is pressed again. In the tank off mode, the manual drain button is still active, but the mode select button is not.

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Contents Installation and Maintenance Metal Tools Away from These Areas Table of Contents Check Shipment PRE-INSTALLATIONCheck Local Codes Site SelectionWater Total Electrical Service Wiring InstallationMounting the Humidifier Important Please observe the followingConnect Drain Water Fill SupplyPressure in duct is high, see Figure Control Humidistat Control WiringWall Mounted Control Humidistat 10 FtAirflow Switch Duct Mounted Control HumidistatHigh Limit Duct Humidistat Generator a Audible AlarmInstrument Panel START-UP Procedure for Armstrong Series EHU-700 Humidifiers Before Turning on the PowerTurn on Power AT the Circuit Breaker Page Page Troubleshooting Guide Operational Guidelines Tank Contactor OperationMonitoring Stat Demand Manual Drain Mode Monitoring % PowerMonitoring Current Automatic Drain OperationDiagnostic Display Messages EHU-700 DiagnosticsC02 Tank Needs Cleaning C00 Normal Operation C01 High WaterC05 Drain System Failure C04 High Limit CircuitC06 Fill System Failure C07 Overcurrent FailureC09 I/O Diagnostics When Water Conductivity is TOO LOW Water Quality and Treatment for EHU Series HumidifiersGeneral Results When Water Conductivity is TOO HighRemedy RemediesSteam Generator Parts Valves and Mechanical Parts Electrical Parts EHU-700 Parts List Recommended Maintenance Schedule To 2 Days After Start UP MaintenanceSteam Generator Maintenance Month to 1 YearTank Removal and Replacement ALL Models Steam Generator Chemical Cleaning Procedure Page Models EHU-703 and 704, Single and Three Phase Tank DISASSEMBLY, CLEANING, and Electrode ReplacementModel EHU-701, Single and Three Phase Fill and Drain System RepairDrain System Failure Fill System Failure Specifications Autocal ProcedureHumidistat Data Sensor Failure ProtectionSensor Characteristics DimensionsAIR Supply High Limit Humidity Sensor Humidity SET Point Reset by Outside TemperatureHumidistat model number H270-69-13-10-31 Application ExampleDimensional Information

EHU-701, EHU-700 Series, EHU-704, EHU-703 specifications

Armstrong World Industries has long been a leader in the ceiling and wall solutions industry, and its EHU-700 Series exemplifies the commitment to innovation and quality. The EHU-700 Series, which includes models such as the EHU-703, EHU-704, and EHU-701, is designed for a variety of commercial applications, combining aesthetic appeal with superior performance characteristics.

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In summary, the EHU-700 Series, including the EHU-703, EHU-704, and EHU-701 models, showcases Armstrong World Industries' dedication to quality and innovation. With unparalleled acoustic performance, durability, installation convenience, and sustainability, these ceiling panels are ideal for a wide array of commercial environments, proving to be a valuable investment for modern architectural needs. Their combination of functionality and design ensures that they meet the demands of today's dynamic spaces.
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