Bard Economizer Installation Instructions

Economizer Features

• One-piece construction for easy installation with a direct-drive actuator that eliminates linkage.
• Exhaust air damper with a positive closed position to provide exhaust air capability and prevent pressurization of tight buildings.
• Actuator Motor: 24-volt, power-open, spring-return, direct-coupled with stall protection. Features a self-centering shaft clamp and access cover for easy replacement and maintenance.
• 10K outdoor temperature sensor.

General Information

The economizer should only be installed by a trained heating and air conditioning technician. These instructions serve as a guide for the technician installing the economizer package.

The economizer housing is shipped in one carton containing the electrical harness, miscellaneous hardware, and installation instructions. Any wall mount unit equipped with an economizer must also have a factory/field installed low ambient control.

Unpacking

Upon receipt, compare the model number on the shipping label with the accessory identification information on the orders and shipping document to verify the correct accessory was shipped. Inspect the carton housing of each economizer assembly. Before signing the freight bill, verify that all items have been received and there is no visible damage. Note any shortages or damage on all copies of the freight bill. Contact the carrier immediately, preferably in writing, requesting inspection by the carrier's agent. Concealed damage not discovered until after loading must be reported to the carrier within 15 days of receipt.

Description

ECON-NC economizers are designed for use with Bard wall mount series air conditioners and heat pumps equipped with low ambient controls and field-installed controllers. They are electromechanical economizer systems designed to provide "free" cooling when the outdoor air temperature is cool enough to provide the needed cooling without running the compressor, or in addition to the compressor. When cooling is required, the system automatically takes advantage of cold outdoor air when available and uses it for first stage cooling, reducing the need to run the air conditioning compressor, thus providing lower operating costs and increasing the service life of the equipment. If the outdoor air temperature is too warm to be sufficient for cooling, the dry bulb outdoor air temperature sensor detects the condition and automatically closes the outdoor air intake/exhaust damper, opens the return air damper, and switches to compressor-only operation. ECON-NC Series economizers are not for use with variable capacity ECU models.

Table 1: Economizer Application

Note: Low ambient control is required with economizer for low temperature operation.

Installation of Field-Installed Economizer

Basic Installation

WARNING: Electrical shock hazard. Disconnect remote electrical power supply or supplies before servicing. Failure to do so could result in electric shock or death.

Preparing Unit for Economizer Installation

1. Disconnect power to the unit.
2. Unpack the economizer assembly, which includes the integral economizer with attached electrical harness, mixed air sensor, body panels, miscellaneous hardware, and installation instructions.
3. From the existing wall mount unit, remove and save (or discard) as directed (see Figure 1): Blower access panel and screws (save), Ventilation access panel (discard), Filter access panel (discard).
4. Remove and discard the exhaust cover plate (save screws).
5. Install new condenser exhaust plate with screen over the opening into the condenser section (see Figure 2).
6. Verify the type of filter racks in the unit. The unit may include either a filter partition and tray assembly, or two separate filter brackets.

If the unit contains a partition and tray assembly, this may be left as-is for the ventilator installation. Continue to Step 1 of Economizer Installation on page 8.

If the unit contains two separate filter brackets, remove the filter brackets. If the filter brackets are mounted flat, they can be used with the economizer. If the brackets are set at a 30° angle, they must be removed, discarded, and fill plates added (see Step 7). The circuit breaker offset plate must be loosened and moved slightly to gain access to several of the screws holding the filter brackets in place. Tighten the screws holding the control panel after the filter brackets have been removed.

Figure 1: Wall-Mount Unit Access Panels

Figure 1 Description: Diagram showing the location of the Blower Access Panel, Filter Access Panel (discarded), Ventilation Access Panel (discarded), Circuit Breaker Access Door, Inner Control Panel Door, Control Panel Door, Filter, and Condenser Exhaust Plate (discard and save screws).

Figure 2 Description: Exploded view diagram of the Condenser Exhaust Plate with Screen, showing the partition cover plate, screen media facing partition, condenser partition, and screw locations.

Figure 3 Description: Diagram illustrating filter and filter brackets, showing a left filter bracket and a right filter bracket with a 30° reference angle, and a filter. It also shows the thermistor location and a mounting hole located behind the circuit breaker offset plate for the 30° right filter bracket.

If filter brackets were removed in Step 6, proceed to Step 7. If the brackets were not removed, proceed to Outdoor Air Sensor Installation on page 8.

7. Install filter bracket fill plate as shown in Figure 4 on page 6.
8. Install provided filter brackets on economizer (see Figure 4).

Figure 4 Description: Diagram showing the installation of the filter bracket and filter bracket fill plate. It illustrates the placement of the fill plate with two screws, and the short and long filter brackets with regular screws.

Figure 5 Description: Diagram showing the Return Fill Plate and Vent Installation for units with a partition assembly. It depicts the right hand unit and left hand unit, with labels for control panel location and instructions to fasten the fill behind the filter tray with screws. It also shows the right and left hand unit vent assembly and notes to use a 52" wire harness for left hand units only.

Outdoor Air Sensor Installation

1. Remove and save both side grilles and screws.
2. Install the outdoor temperature sensor in the lower condenser section on the same side as the control panel with two (2) screws provided as shown in Figure 6.
3. Route the wire harness through the condenser base and into the control panel (see Figure 7). Secure with two wire ties (provided). Push harness up through the grommet in the bottom of the control panel. Secure with wire ties (provided) to the other wires in the grommet. Ensure the wire harness cannot contact moving parts or copper tubing. Replace side grilles.

Figure 6 Description: Photograph showing the installation of the outdoor air sensor, illustrating its placement and wiring.

Figure 7 Description: Photograph showing how to route the wire harness through the condenser base and into the control panel, secured with wire ties.

Economizer Installation

1. Connect the 12-pin male plug into the female plug in the side of the control panel as shown in Figure 8. See wiring diagram on page 11.

Figure 8 Description: Diagram of the Control Panel showing the low voltage terminal board, female 12-pin connector, and wiring connections to the sensor and thermostat.

Figure 9 Description: Diagram illustrating the Mixed Air Temperature Sensor Installation. It shows the left hand unit wire route, top of outdoor coil, mounting screw, and the wire harness from the vent package plugging into the front side of the control panel. It also provides instructions for sliding the vent package and aligning it with the control panel and return air opening.

2. Remove (and discard) left and right filter brackets from the economizer assembly if existing wall mount unit brackets are in place.
3. For units with a partition and tray assembly, install the return fill plate. Refer to Figure 5 on page 7.
4. Insert the economizer into the opening in the wall unit between the filter rack (if not removed earlier) and the condenser section, being careful not to tear unit insulation. To clear blowers, position the economizer at a 45° angle under the blowers. Fully seat the economizer assembly to the rear of the wall unit cavity. Slide the economizer to the right and line up with the return air opening in the back of the wall unit.
5. Left hand units: Use the 52" wire harness (provided). Plug the 12-pin male connector into the female plug in the control panel. Route the wire harness to the back of the economizer and attach to the upper fill plate using the push-in wire ties provided (see Figure 9). Plug the male 12-pin connector from the economizer actuator into the wire harness.
6. Right hand units: Plug the 12-pin male connector straight into the female plug in the control panel. Plug the outdoor sensor wire connectors into the spade connectors on the 12-pin male plug (orange wires) as shown in Figure 10.

Figure 10 Description: Photograph showing outdoor sensor wire connections, specifically highlighting the orange wire connections to the spade connectors.

6. Remove the front door, control door, and mist eliminator from the economizer hood assembly.
7. Lift the economizer hood to the unit and hold in position. Line up the four (4) holes in the outer economizer hood door (two on each side) with the corresponding holes in the unit and mount the economizer hood to the unit with four (4) screws.
8. Connect the vent option front to the vent hood door (see Figure 11) using ten (10) screws (supplied).
9. Re-insert the filter into the filter brackets. The arrow on the filter should point up.
10. Install the filter door.
11. Attach the blower access panel.

Figure 11 Description: Diagram showing the Vent Option Door Installation, including the filter door, mist eliminator, block off plate, and screw locations for securing the door and sealing between the vent option and door.

Economizer Checkout

1. Attach the wall unit outer and indoor control panel doors.
2. Turn power to the unit on.
3. After confirming economizer operation, attach the economizer hood mist eliminator (with airflow arrow pointed towards the unit), control door, and front door.

Control Wiring Connection Diagram

See the economizer wiring diagram in Figure 12. For low voltage connections, refer to the wall-mount unit installation instructions manual.

Figure 12 Description: Wiring diagram for the Economizer ECON-NS*. It shows connections for the damper motor, 10K OD temperature sensor, and the 12-pin vent plug, indicating wire colors and terminal functions such as 24V common, 24V input signal, and 0-10V DC input signal.

Airflow Paths

Figure 13 Description: Diagram illustrating the 100% Outside Airflow Path, showing the flow of supply air, cooling coil, air filter, mist eliminator, outdoor air, return air, and exhaust air.

Figure 14 Description: Diagram illustrating the Mixed Airflow Path, showing the flow of supply air, cooling coil, air filter, mist eliminator, outdoor air, return air, and exhaust air.

Figure 15 Description: Diagram illustrating the 100% Closed Loop Airflow Path, showing the flow of supply air, cooling coil, air filter, mist eliminator, damper blade, outdoor air, return air, exhaust air, condenser air, and condenser coil.