Bard MULTI-TEC Wall-Mount Air Conditioner Service Manual

General Information

The Bard air conditioning system comprises MULTI-TEC wall-mounted units, compatible with the LC6000 supervisory controller, th-Tune single-unit controller, or Bard PGD stand-alone display. For multiple units, the LC6000 is mandatory. These units are designed for telecom/motor control center rooms, offering full cooling airflow in free cooling mode and exhausting air through the unit itself. Units are factory-charged with refrigerant and may include optional electric heat.

Installation should be performed by trained technicians. The refrigerant system is pre-assembled and charged. Units can be used with or without ductwork, with provided flanges for duct attachment.

Important Notes:

• Adhere to national and local codes.
• Sizing should follow ACCA methods. Duct installation should comply with NFPA standards.
• Check for shipping damage upon receipt and contact the carrier immediately if found.
• Units must remain upright.

Additional Publications: Consult standards from ANSI/NFPA and ACCA for detailed guidance.

Safety Warnings:

• ⚠️ Electrical shock hazard. Use only trained personnel. Disconnect power before servicing.
• ? Fire hazard. Maintain 1/4" clearance between supply air duct and combustible materials.
• ?️ Sharp metallic edges. Use protective gear.
• ?️ Heavy item hazard. Use multiple people for handling.

Using the TEC-EYETM

The TEC-EYE hand-held diagnostic tool is essential for unit setup, diagnostics, and configuration. It connects to the unit logic board via an RJ11 connector.

TEC-EYE Interface:

• ALARM KEY: View active alarms, silence audible alarms, reset alarms.
• MENU KEY: Access Main Menu.
• ESCAPE KEY: Return to previous menu, cancel changes.
• UP KEY: Navigate up, increase value.
• ENTER KEY: Accept value, advance cursor.
• DOWN KEY: Navigate down, decrease value.

Password Levels: User (2000), Technician (1313), Engineer (9254).

Screen Structure: Accesses Quick Menu (Setpoints, Information, Alarm Log) and Main Menu (System Config, Adv Sys Config, I/O Config, On/Off, Alarm Logs, Settings, Initialization, Logout).

Status Screen: Default screen showing unit address, date, time, temperatures (Return Air, Mixed Air, Outdoor Air), humidity, dewpoint, and unit status messages (e.g., "LC Online", "Cooling", "Heating Active").

Quick Menu: Accessible from the Status screen via UP/DOWN keys. Allows quick access to Setpoints, Information, and Alarm Log.

Setpoints: Allows adjustment of cooling and heating setpoints. Values are synced with the LC6000 controller.

Information Screens: Display unit run hours, averages, and software version information.

Alarm Log: Records alarm occurrences and clearing times.

Addressing Wall-Mount Units: Each unit requires a unique address (1-14) for LC controller operation. Set via Main Menu > Sys Config > Unit Address.

Setting Unit Zone: Assign units to specific zones via Main Menu > Sys Config > Unit Zone.

Software Versioning: Format MTS1000.X.Y.Z. Check Bard website for latest versions.

Executing a Self Test: Verify unit functionality via Main Menu > Sys Config > Self Test > ON. The unit cycles through various operations (damper, compressor, heat).

Changing Free Cooling Type: Options include None, Drybulb Only, Temperature and Humidity (Default), and Enthalpy. Configured via Main Menu > Sys Config > Free Cooling Config.

Entering Model/Serial Number: Manually entered via Main Menu > Adv Sys Config.

Alarms

Alarm conditions activate a red LED and optionally an audible signal. Acknowledged by pressing the ALARM key.

Clearing Alarms: Press ALARM key, navigate to reset screen, hold ALARM key for 3 seconds. Screen displays "NO ALARMS" if successful.

Clearing Alarm Logs: Main Menu > Settings > Initialization > Delete alarm logs? > YES.

Alarm Adjustment: Parameters like Mixed Air Alarm (Diff Lo, Diff Hi, Del), Refrigerant Low Pressure (Delays), Refrigerant High Pressure (no parameters), Economizer Damper (Open Del, Close Del), and Freezestat (Low Temp, Delay, Reset Temp, Reset Del) can be adjusted via Main Menu > Sys Config > Alarm Config.

Control Operation

On/Off Control: Managed via TEC-EYE: Main Menu > ON/OFF.

Blower Control: ECM blower has multiple speeds: Low (Balanced Climate), Nominal (Normal), High (High Sensible). Balanced Climate and High Sensible speeds are available when connected to LC6000.

Balanced Climate Mode: Enhances latent capacity for dehumidification. Enabled/disabled via Main Menu > Adv Sys Config > Blower Settings > Balanced Climate.

Temperature Control: Units operate based on return air temperature in orphan mode or commands from the LC6000. Cooling and heating sequences involve multiple stages based on setpoints and differentials.

Cooling Sequence: Utilizes economizer and mechanical cooling stages. Staging parameters (Diff On/Off) adjusted via Main Menu > Sys Config > Cooling Setup.

Heating Sequence: Utilizes electric heat stages. Staging parameters (Diff On/Off) adjusted via Main Menu > Sys Config > Heating Setup.

Free Cooling: Economizer operation is prioritized before mechanical cooling. Types include None, Drybulb Only, Temperature and Humidity, and Enthalpy. Conditions for each type are detailed.

Economizer Modulation: Damper output modulates to maintain mixed air temperature. Parameters (Mixed FC Set, Gain, Integral, Derivative, Min Position) adjusted via Main Menu > Sys Config > Unit Config.

Emergency Cooling: Activated when return air temperature exceeds 95°F or commanded by LC6000. Economizer operation is modified to maximize cooling.

Unit Disable: Can be disabled via a dry contact on Input DI1. Configured via Main Menu > IO Config > Digital In Config C1.

Compressor: Enabled based on call for cooling/heating. Features minimum run/off times and anti-short cycle protection.

Dehumidification:

• Dehumidification Off: Humidity below setpoint (default 60% RH).
• Passive Dehumidification: Humidity rises to setpoint (default 70% RH). Economizer disabled, blower speed reduced, compressor energizes.
• Active Dehumidification: Humidity rises to higher setpoint (default 80% RH). Controller calculates demand and stages units.
• Electric Reheat Dehumidification: Factory option. Disables economizer, uses AC to cool/dehumidify, then electric reheat to extend run time and mitigate overcooling. Controlled by LC6000.
• Mechanical Dehumidification: Factory option. Uses AC and a 3-way valve to extend run time. Economizer disabled. Controlled by LC6000.

General Refrigerant Information

Units use R-410A refrigerant and polyol ester oil. Key points:

• Use separate, R-410A rated service equipment.
• R-410A operates at higher pressures than R-22.
• Polyol ester oil is hygroscopic; limit atmospheric exposure.
• Charge with liquid refrigerant.
• Topping off charge is possible after leaks, but reclaiming, evacuating, and recharging to nameplate is recommended.

Safety Practices: Use gloves and safety glasses. Do not mix refrigerants. Do not inhale R-410A vapor. Do not burn R-410A. Handle cylinders with care.

Cooling Pressures: Table 5 provides nominal low and high side pressures for various models under different ambient conditions. Use as a guide; recharge to serial plate charge if in doubt.

Componentry

High Pressure Switch: Opens at 650 psi on ACP* models.

Three Phase Scroll Compressor Start Up: Verify correct rotation direction to prevent damage. Reverse rotation causes elevated sound and reduced current draw. Reverse leads if necessary.

Phase Monitor: Protects 3-phase compressors from incorrect phasing, voltage imbalance, or frequency deviation.

Condenser Fan Operation: Motors are typically two-speed, factory wired to high speed. Can be rewired to low speed for reduced sound. Low Ambient Control (LAC) modulates fan speed based on refrigerant pressure.

Compressor Control Module (CCM): Standard on all models. Includes delay-on-make, short cycle protection (adjustable), high pressure detection, test mode, and brownout protection (adjustable via DIP switches).

Pressure Service Ports: High and low pressure ports are available. Use special tools for Coremax valves; do not use Schrader tools.

Outdoor Fan Motor: Proper placement and clearance are critical. Refer to Figure 32 for fan blade setting dimension 'A'.

Maintenance and Troubleshooting

Standard Maintenance:

1. Disable system via LC6000, turn off AC breakers.
2. Inspect and clean condenser and evaporator coils.
3. Manually spin fan/blower motors (permanently lubricated).
4. Inspect free cooling damper actuator and linkage.
5. Install new air filters.
6. Inspect control panel: check for pests, contactor condition, wiring tightness, and signs of overheating.
7. Ensure supply/return registers are unobstructed and not recycling air.
8. Re-assemble unit, restore power, enable system.

Removal of Fan Shroud: Disconnect power, remove grilles, unscrew shroud, disconnect motor wiring, slide assembly out. Reverse for re-installation. Check fan blade clearance.

Filters: Standard units use two 20"x20"x1" throwaway filters. 1" and 2" filters are available. Removal is from the outside via the front control panel cover. Airflow arrows must point correctly.

Switching Filter Sizes: Involves adjusting filter support brackets and slots for 1" or 2" filters.

Dirty Filter Switch: Located on filter partition. Indicator light and reset switch are on the access opening. Adjustment is made via a knob on the switch, calibrated against airflow restriction (e.g., using cardboard). Recommended starting point is 0.4" W.C.

Troubleshooting Nidec SelecTech ECM Motors:

• If Motor is Running: Check for programmed delays, correct control inputs, open dampers/filters, duct static pressure, and "Continuous Fan" input.
• If Motor is Not Running: Verify high voltage and ground at motor connections (L/L1, G, N/L2). Check low voltage communication signals from thermostat/control.

Sensor Data: Tables 7, 8, and 9 provide Temperature/Resistance and Humidity/Voltage data for various sensors (8301-067 Outdoor Temp/Humidity, 8408-044 Return Air/Suction Sensor).

Alarm Index: Table 10 lists alarm index numbers, variable names, and corresponding PGD displayed alarm descriptions for unit status monitoring.