OPERATION AND SERVICE INSTRUCTIONS

Table of Contents

• Model Nomenclature: 3
• Description: 3
• Application: 3
• Blade Adjustment for Desired Ventilation Air: 6
• Balanced Climate™ Mode: 6
• Figures:
  • Figure 1: Programmable Thermostat Connections for QCRV-F3 with Heat Pumps: 4
  • Figure 2: Non-Programmable Thermostat Connections for QCRV-F3 with Heat Pumps: 5
  • Figure 3: Blade Adjustment for Ventilation Air: 6
  • Figure 4: Call for Ventilation With or Without Compressor Operation: 9
  • Figure 5: Call for Compressor or Fan Only with Ventilation Off: 10
  • Figure 6: Wiring Diagram: 11
• Graphs:
  • Graph 1: Q24H4 CRV Ventilation Delivery: 7
  • Graph 2: Q30H4 CRV Ventilation Delivery: 7
  • Graph 3: Q36H4 CRV Ventilation Delivery: 8

Safety Precautions

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

WARNING: Exposed moving parts. Disconnect all electrical power before servicing. Failure to do so can result in severe injury or amputation.

CAUTION: Sharp metallic edges. Take care and wear appropriate protective devices to avoid accidental contact with sharp edges. Failure to do so can result in personal injury.

QCRV-F3 Features

• Exhaust air damper: Built-in with positive closed position. Provides exhaust air capability to prevent pressurization of tight buildings.
• Actuator motor: 24 volt, power open, spring return with built-in torque limiting switch.

Model Nomenclature

The QCRV-F3 model designation breaks down as follows:

• QCRV: Q-TEC Commercial Room Ventilator
• F: Fixed (24V ON/OFF)
• 3: Chassis Size (3-2, 2.5 & 3 Ton)

Description

The Bard QCRV-F3 Commercial Room Ventilator is an electromechanical ventilation system designed to provide fresh outdoor air to meet indoor air quality standards. It is intended for use with specific Bard heat pump models as designated on the front page of this manual.

This unit features an internally mounted damper with exhaust capabilities, designed to supply up to 50% fresh air. The damper blade is powered by a 24 VAC motor that provides a power-open function and a spring-return action upon power loss. The damper opens when the 'A' terminal is energized. Ten different airflow settings can be achieved by adjusting the blade stop screws located under the fresh air blade.

When installed in compatible Bard heat pump models, the QCRV-F3 integrates exhaust provisions. As the damper blade opens to admit fresh air, it simultaneously opens an exhaust relief. This exhaust air is directed into the unit's condenser section, where the condenser fan assists in drawing it out during cooling or heat pump operation.

Application

The quantity of outside fresh air introduced into a structure by the QCRV-F3 is influenced by several factors within the duct system: return air duct static pressure, supply air duct static pressure, and indoor blower motor speed. The damper blade's open position setting also plays a crucial role.

Refer to Graphs 1-3 on pages 7-8 for specific ventilation air delivery rates based on different blade settings and duct static pressures. For applications without ductwork, utilizing return air filter grilles and supply grilles, a supply air static pressure of 0.00 is assumed.

Blade Adjustment for Desired Ventilation Air

The amount of ventilation air supplied by the commercial room ventilator depends on four primary factors:

1. Return air duct static pressure drop.
2. Supply air duct static pressure drop.
3. Indoor blower motor speed.
4. Damper blade open position setting.

To determine the correct blade setting for the required airflow, consult the appropriate graph on the following pages. Adjust the blade stop screws accordingly, as illustrated in Figure 3.

Note: The unit is shipped from the factory with the blade set in the #2 position, which provides approximately 100-150 CFM of fresh air.

Balanced Climate™ Mode

The Balanced Climate™ mode is suitable for both duct-free and ducted applications where the total static pressure is below 0.2" W.C. ESP. When this mode is activated, the blade stop screw positions must be adjusted to allow approximately 28% more outdoor air to ensure minimum ventilation requirements are met.

Thermostat Connections

Detailed wiring diagrams are provided for connecting thermostats to the QCRV-F3 unit. These diagrams include specific instructions for both programmable and non-programmable thermostats, as well as notes regarding jumper installations and configuration settings.

Ventilation Delivery Graphs

The following graphs illustrate the ventilation airflow (in CFM) delivered by different QCRV-F3 models at various damper positions under specific static pressure conditions.

Airflow Diagrams

The following figures illustrate the airflow paths within the QCRV-F3 unit under different operating conditions.

Wiring Diagram