Aprilaire Model 8145 and 8145NC Fresh Air Ventilator

Model 8145 and 8145NC Overview

The Aprilaire Model 8145 and 8145NC Fresh Air Ventilators are designed to introduce a controlled amount of fresh outdoor air into modern, energy-efficient homes. The system involves ducting the ventilator's inlet to an outdoor air source and its outlet to the HVAC system. Once installed, the unit can be powered on, the required ventilation rate set, and desired temperature limits configured.

When installed and set up correctly, these ventilators meet the mechanical ventilation requirements for:

• Energy Star Certified Homes
• EPA Indoor airPLUS
• 2012-2018 International Residential Code (IRC)
• 2012-2018 International Energy Conservation Code (IECC)
• California Energy Commission Title 24
• ASHRAE Standard 62.2-2010
• ASHRAE Standard 62.2-2013 & 2016

Safety Instructions

WARNING:

• 120 Volts can cause serious injury from electric shock. Always disconnect electrical power before installation or servicing and keep it disconnected until work is completed.
• Sharp edges can cause serious injury from cuts. Exercise caution when cutting plenum openings and handling ductwork.

CAUTION:

• Read all instructions before beginning installation.
• Improper installation may cause property damage or injury. Installation, service, and maintenance must be performed by a qualified service technician.

Specifications

Figure 1: Dimensions (inches). The main unit has a height of approximately 23.41 inches, a width of 19.66 inches, and a depth of 13.01 inches. The inlet collar is round for a 6" diameter duct, and the outlet collar is oval for a 6" diameter duct. The dimensions for the outlet collar are approximately 12.25 inches by 13.906 inches. Note that the ventilation controller is not included on Model 8145NC.

Installation

Install Electrical Outlet

Install a standard NEMA 5-15 receptacle suitable for the location, near where the ventilator will be installed. The ventilator comes equipped with a 6-foot power cord with a standard 3-prong plug.

Ventilator Location and Orientation

If the ventilator's outlet is not ducted, or if short sections of flexible duct are attached, mount the unit to minimize access to moving parts. Mount the blower with the lowest exposed moving parts at least 8 feet (2.4 m) above floor or grade level. Mount the blower at least 3.3 feet (1.0 m) from any accessible duct opening. Choose a location within 6 feet of the power outlet. Ensure sufficient space for filter removal and service, as depicted in Figure 2. The ventilator can be mounted in any orientation.

Figure 2: Clearances for Servicing. This diagram illustrates the necessary clearances around the ventilator for maintenance. It shows 12 inches required for filter access and 24 inches for fan access.

Mount the Ventilator

Select the appropriate mounting brackets (small or large) as shown in Figure 3. For wall mounting or hanging from joists, use four small brackets. For mounting between floor joists, use four small brackets for 13" on-center joists or two small and two longer brackets for 16" on-center joists. Snap the brackets into their designated locations on the unit (Figure 4). Use mounting locations nearest the cover for between-joist or rafter mounting, and locations near the bottom for surface mounting (walls, ceilings, or joist bottoms). Secure the brackets to joists or a strong platform using the provided #10 x 3/4" screws. The ventilator weighs approximately 15 pounds and should not be secured to drywall alone.

Figure 3: Brackets. This figure displays the different types of mounting brackets available for the ventilator.

Figure 4: Mounting Bracket Positioning. This diagram shows three mounting configurations: Between Joists, Hanging Installation, and Surface Mount, illustrating how the brackets attach to the ventilator and the structural elements of the building.

Mount Intake Hood

Install a weather-tight hood with a bird screen. Cut a hole in the exterior wall large enough for a 6" insulated flexible duct. Pull the duct through the hole and attach it to the hood's collar using metal foil tape or a plastic zip-tie. Pull the insulation and vapor barrier over the duct and tape it to the collar. Ensure the end of the insulation is sealed to prevent condensation. Press the hood against the outside wall, secure with screws, and seal the perimeter with caulk.

Install Ductwork

Install 6" diameter flexible, insulated ductwork connecting the round inlet collar of the ventilator to the intake hood, and the oval outlet collar to the HVAC system's return side (refer to Figure 5). Ensure the end of the insulation is sealed to prevent condensation.

Figure 5: Ducting in Upflow and Horizontal HVAC Systems. This figure illustrates two typical installation scenarios. The 'Typical Attic Installation' shows the fresh air intake hood on a gable end wall, ducting to the ventilator, and then to a return mixing box connected to the furnace/air handler. The 'Typical Basement Installation' shows the intake hood on an outside wall, ducting to the ventilator, and then to the furnace/air handler, indicating airflow direction.

Wiring

Model 8145NC – Wiring to Various Controls

Suggested controls include Aprilaire IAQ Control Models 8910, 8910W, or 8920W; Aprilaire Thermostat Models 8620 or 8620W; or Aprilaire Model 8120X Digital Ventilation Controller. Wire the controls to the HVAC equipment and any other IAQ accessories according to the literature provided with those controls.

Figure 6: Wiring to IAQ Control. This diagram shows the terminal connections for an IAQ Control Module, illustrating how to wire various sensors and the ventilator (VENT terminal).

Figure 7: Wiring to Thermostat. This diagram details the wiring connections for a Model 8620/8620W Thermostat to the ventilation control system, including connections to the VENT terminals.

Figure 8: Wiring to Model 8120X. This diagram illustrates the wiring for a Model 8120X Digital Ventilation Controller, showing connections to the ventilator's VENT terminals.

NOTE 1: An outdoor temperature sensor must be installed to utilize outdoor temperature limits for ventilation control.

Model 8145NC – Test Mode

After ducting and wiring are complete, plug in the ventilator and restore power to the HVAC system. Ensure the outlet switch is on. Use the installed control to complete a circuit between the VENT terminals on the 8145NC. Verify the ventilator blower starts and the damper opens. If wired to control the HVAC blower, confirm it operates. Measure the airflow (CFM) and adjust ventilation settings per the control's instructions.

Model 8145NC – Sequence of Operation

Refer to the installation manual provided with the control wired to the Model 8145NC.

Model 8145 – Wiring the Control to the HVAC System

NOTICE: Disconnect power to the HVAC system during wiring to avoid electrical shorts.

1. Remove the control from its mounting plate (Figure 9) and set it aside safely. 2. Run a 6-conductor (min.) cable for furnace/AC or a 7-conductor (min.) cable for heat pumps between the control and the HVAC system. 3. Wire to the HVAC system per Figure 10 (furnace/AC) or Figure 11 (heat pump).

Figure 9: Remove Control from Mounting Plate. This diagram shows how to detach the control unit from its mounting plate, indicating the control connector.

Figure 10: Wiring Ventilation Control to a Furnace. This diagram illustrates the wiring between a thermostat, a ventilation control, and a furnace. It details connections for 24 VAC (R & C), Cooling (Y), Heat (W), Fan Input (GS), and Fan Output (GH), with the VENT terminal connecting to the ventilator.

Figure 11: Wiring Ventilation Control to a Heat Pump. This diagram shows wiring for a heat pump thermostat, including connections for Compressor (Y), 1st Stage Aux. Heat (W1), Rev. Valve (O), and Fan Input/Output (GS, GH), connecting to the ventilation control and ventilator.

Model 8145 – Connecting the Control to the Ventilator

Plug the Control Connector into the back of the control unit as shown in Figure 12. Route the wire through the channels and reattach the control to the mounting plate. Restore HVAC power and plug in the ventilator.

Figure 12: Plug the Control into the Ventilator. This diagram shows the control connector being inserted into the back of the ventilator's control unit.

Operation

The ventilator display may appear faint normally; pressing any button will activate it at full power. The display shows the ventilation time setting (minutes/hour), mode of operation (Code or Comfort), and whether the HVAC fan is running during ventilation. Green lights indicate ventilation is active.

Use the 'Select' button to scroll through settings. Press and hold 'Select' for 5 seconds to enter Test Mode or the Set Up Menu. The 'Up' and 'Down' arrows adjust values. The 'Select' button confirms values and moves to the next menu item.

A dedicated button allows overriding the calculated ventilation time (6-60 minutes/hour). Press and hold this button to turn ventilation OFF. To revert to the calculated setting, cycle through the entire Set Up Menu.

Test Mode

After wiring and setup, Test Mode verifies system components and HVAC fan wiring. Hold 'Select' for 5 seconds to enter. The display will show outdoor temperature (or '-- --' if no external sensor is used). The 'tEst' sequence will activate the ventilator blower and/or damper. The HVAC fan will turn on if wired and configured. Test Mode automatically completes after 45 seconds, returning to the operating display.

Measure Delivered Airflow

Ensure the ventilator is plugged in and wired. Use 1/4" flexible tubing to connect a pressure gauge (set to a range of 1.0" w.c.) to the ventilator's inlet and outlet pressure ports. Connect the gauge's high (+) port to the outlet pressure port and the low (-) port to the inlet pressure port (Figure 13).

For Model 8145NC: Activate ventilation by temporarily setting the control to 60 minutes/hour or by placing a jumper between the VENT terminals.

For Model 8145: Activate ventilation by pressing the 'Up' button to increase the setting to 60 MIN./HR.

Convert the pressure reading to delivered airflow (CFM) using Table 3. If the reading falls between values, use the lower value or interpolate. Interpolation formula: CFM = Lower Value + [(Higher Value – Lower Value) * 10 * (Pressure Reading – Lower Value Pressure)].

Figure 13: Measure Pressure at Inlet and Outlet Pressure Ports. This diagram shows the ventilator with labeled inlet and outlet pressure ports. It illustrates connecting a pressure gauge using flexible tubing to measure static pressure.

Set Up

NOTICE: Before setup, measure the actual ventilation air delivered (CFM) by the installed system.

Navigate the Set Up Menu by holding 'Select' for 5 seconds, then releasing. Use the 'Up' and 'Down' arrows to change values and 'Select' to confirm and move to the next item.

IMPORTANT NOTE: The 8145 control senses outdoor air temperature and humidity. To prevent extended inactivity, set the control mode to CODE, or if using cFrt (comfort), set RH limits to OFF.

Once all Set Up Menu options are entered, the control will display 'donE'.

Rater/Inspector Verification

To verify the ventilation time setting, press 'Select' to cycle through the calculated Required Continuous CFM and the Measured CFM. If values do not match, re-enter the Set Up Menu to adjust floor area, number of bedrooms, or measured CFM.

The calculation for ventilation time setting (compliant with ASHRAE Standard 62.2-2010) is:

Minutes per Hour = 60 * (Required Continuous CFM / Measured CFM)

Required Continuous CFM is calculated as:

Required Continuous CFM = ((Floor Area ft² * 0.01) + (No. of Bedrooms + 1) * 7.5)

Sequence of Operation

"CODE" SETTING

Ventilation runs for the set minutes per hour during a heating, cooling, or fan call. If outdoor temperature is outside the set limits, ventilation may be restricted or occur only during heat calls. If HVAC equipment doesn't provide enough ventilation time, the control will activate ventilation without a call if temperature limits are met. The HVAC blower will also activate if wired and set up.

If outdoor temperature remains out of range, the cycle period automatically adjusts from 1 hour to 4, 8, 12, and finally 24 hours to compensate for ventilation effectiveness as defined by ASHRAE Standard 62.2-2010. At the 24-hour cycle period, ventilation will occur to meet requirements regardless of temperature.

"COMFORT" SETTING

Ventilation runs for the set minutes per hour during a heating, cooling, or fan call, provided outdoor air temperature and indoor RH are within the specified high and low limits. If HVAC equipment doesn't provide enough ventilation time, the control will activate ventilation without a call if temperature and RH limits are met. The HVAC blower will also activate if wired and set up.

Filter Cleaning

The fresh air filter should be removed and cleaned approximately every six months. Check after the first three months to determine cleaning frequency. After cleaning the internal filter, clean the screen on the fresh air intake hood outside the house, as a clogged intake hood is a common cause of reduced ventilation.

To clean the ventilator filter (Figure 14):

1. Flex the outside edges of the filter door to disengage it from the housing.
2. Lift the filter door and remove the filter.
3. Rinse the filter with water and shake off excess moisture.
4. Replace the filter and press the outside edges of the filter door to snap it back into place.

Figure 14: Filter Cleaning. This diagram shows how to open the filter door by flexing its edges, remove the filter, and then re-secure the door.

Internal Schematics

Figure 15: Model 8145 Internal Schematic. This schematic details the internal components of the Model 8145, including the blower motor, run capacitor, damper motor, and power PCB assembly. It shows wiring connections for power (L1, L2, N, GND) and control terminals (R, C, Y, W, O, Gs, Gh, VENT, ODT). Capped red and white wires inside the filter door are for powering the control directly from the PCB if not wired to the HVAC system.

Figure 16: Model 8145NC Internal Schematic. This schematic illustrates the internal components of the Model 8145NC, similar to the Model 8145, showing the blower, run capacitor, damper motor, power PCB assembly, and terminal block connections for power and control signals.

Limited Warranty

Your Aprilaire Fresh Air Ventilator is warranted for five (5) years from the date of installation against defects in materials or workmanship. Research Products Corporation will supply a replacement for any defective component returned within the warranty period. This warranty does not cover labor costs or defects in materials or workmanship furnished by the installer. Implied warranties are limited to five years. This warranty is void if the unit is not installed by a qualified HVAC contractor. Some states may have different warranty rights.

Warranty Registration: Register online at www.aprilaire.com or by mail. Registration information will not be sold or shared.

Contact Information:
AprilairePartners.com
P.O. Box 1467
Madison, WI 53701-1467
Phone: 800.334.6011
Fax: 608.257.4357
Printed in USA
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