Aprilaire Model 8191 & 8192 Ventilator with Dehumidification
Installation and Operating Instructions
Introduction and Compliance Statement
The Aprilaire Model 8191 and 8192 Ventilator with Dehumidification is designed to introduce fresh outdoor air into modern, energy-efficient homes while simultaneously removing excess moisture. Installation involves connecting the ventilator's inlet to an outdoor air intake and its discharge to the HVAC system's return side. The unit is then plugged in, and the desired ventilation and humidity levels are set.
The control system allows for high-temperature limits to prevent outdoor air intake during the hottest parts of the day. It automatically compensates for missed ventilation by introducing additional outdoor air during cooler periods. This system meets the mechanical ventilation requirements of ASHRAE 62.2-2010, ensuring ventilation occurs at least one hour out of every four. When properly installed and set, the units comply with:
- Energy Star Certified Homes, Version 3
- EPA Indoor airPLUS, Version 1
- 2012 International Residential Code (IRC)
- 2012 International Energy Conservation Code (IECC)
Specifications
| Feature | Model 8191 | Model 8192 |
|---|---|---|
| Weight | 67 lbs. | 75 lbs. |
| Moisture Removal Capacity | 70 pints per day @ 160 CFM (AHAM DH-1-2008 80°F, 60%RH Conditions) | 95 pints per day @ 265 CFM (AHAM DH-1-2008 80°F, 60%RH Conditions) |
| Power | 115 VAC, Single Phase, 60Hz; 9A minimum circuit ampacity; 6.3A operating current @ 80°F, 60%RH | 115 VAC, Single Phase, 60Hz; 12A minimum circuit ampacity; 8A operating current @ 80°F, 60%RH |
| Inlet Air Conditions | Ventilation: 40°F – 140°F, 0%RH – 99%RH (non-condensing); Dehumidification: 50°F – 104°F, 40°F dew point minimum | |
| Filter | MERV 8, washable | |
Model 8191 Ventilation Performance
| External Static ("w.c.) | Airflow (CFM) | Power (W) | Current (A) | CFM/watt | CFM/watt FAN ONLY* |
|---|---|---|---|---|---|
| 0 | 160 | 63 | .57 | 2.54 | 4.48 |
| 0.1 | 140 | 63 | .56 | 2.22 | 3.97 |
| 0.2 | 120 | 63 | .56 | 1.90 | 3.55 |
| 0.3 | 100 | 63 | .56 | 1.59 | 3.04 |
| 0.4 | 70 | 62 | .56 | 1.13 | 2.50 |
*Unit as just a ventilator (without filtration or dehumidification) provides 245 CFM and uses 69 watts, or 3.55 CFM/watt at 0.2"w.c., meeting the 2012 IECC fan efficacy requirement.
Model 8192 Ventilation Performance
| External Static ("w.c.) | Airflow (CFM) | Power (W) | Current (A) | CFM/watt | CFM/watt FAN ONLY |
|---|---|---|---|---|---|
| 0 | 265 | 153 | 1.35 | 1.73 | 2.84 |
| 0.1 | 245 | 153 | 1.34 | 1.62 | 2.60 |
| 0.2 | 230 | 153 | 1.34 | 1.50 | 2.35 |
| 0.3 | 215 | 153 | 1.34 | 1.41 | 2.13 |
| 0.4 | 200 | 152 | 1.33 | 1.32 | 1.91 |
| 0.5 | 180 | 152 | 1.33 | 1.19 | 1.72 |
| 0.6 | 165 | 151 | 1.32 | 1.10 | 1.50 |
Set Up Ventilator for Installation
IMPORTANT: Cut the strap securing the compressor shipping support bracket and remove the strap and shipping bracket.
Duct Collars: For standard basement and attic installations (fully ducted), use the provided screws to attach the duct collars to the inlet and outlet of the ventilator. The outlet collar includes a backflow damper. The outlet duct collar can be attached to the top or end of the unit; relocate the outlet cover as needed. Ensure at least 4 inches of straight ductwork after the outlet to avoid interfering with the backflow damper function.
Control Location: The on-board control can be mounted on the top or relocated to the front of the ventilator. To move the control, remove the front control panel cover, then the filter access door and filter. Detach the control by removing four screws, supporting it from below. Relocate the control to the front access hole and secure it with the same screws. Finally, secure the control panel cover to the top of the unit.
Location Considerations: Ensure sufficient clearance around the unit for filter removal and to prevent airflow obstruction. Electrical service access requires removal of a side panel, so allow adequate space. For attic installations, suspending the ventilator is recommended. Always install the ventilator in a condensate pan if located in or above a finished space.
Drain Installation
The drain outlet can be hard-piped using 3/4" nominal drain tubing or connected with the provided fitting and 1/2" clear PVC tubing. Maintain a constant downward slope towards the drain and prevent soft tubing from curling to avoid air lock. Use PVC primer and cement for PVC connections.
Leveling
Adjust the unit's feet to ensure it is level. Proper leveling is crucial for correct drainage and may be necessary to accommodate drain fittings or a secondary condensate pan.
Condensate Pan, Condensate Pump and Float Switch
Always install the ventilator in a condensate pan when located in or above a finished space, adhering to local codes for draining. If a condensate pump is required, install it within the condensate pan. Install a condensate overflow safety switch (float switch) in the pan. Remove the factory-installed jumper wire between the Float Switch terminals on the control and wire the float switch to the ventilator as shown in the wiring diagram. Overflow safety switches on condensate pumps can also be wired to these terminals.
Ducting and Wiring
Ducting
Install ducting as shown in the diagram. A 6" diameter intake duct is typically sufficient, but larger or multiple 6" ducts can be used for increased ventilation flow. For compliance with Energy Star Certified Homes requirements, install a normally closed damper, such as the Aprilaire Model 6506, in the intake duct.
Wiring
Wire the control to the HVAC system to enable the ventilator to operate when the HVAC system is running, improving outdoor air circulation and utilizing the air conditioner's latent capacity. The ventilation output of a thermostat can be connected to the DH terminals of the Model 8191 or 8192 for control within the living space. Aprilaire thermostats with a ventilation output include models 8840M, 8840, 8920W, 8830, 8910W, 8910, 8820, 8620W, and 8620. An outdoor temperature sensor (included with all models) should be wired to the thermostat for full feature utilization. Wiring to the Rf terminal is optional. The provided wiring diagram shows how to connect the unit to distribute fresh air throughout the home via the HVAC system fan, even when the fan is not otherwise running.
Determine Ventilation Requirements
Calculating Airflow Requirement
The minimum ventilation requirement is calculated using ASHRAE 62.2-2010. The formula is: ASHRAE Airflow in CFM = [House Area in Sq. Ft. x 0.01] + [(Number of Bedrooms + 1) x 7.5]. Use the greater value between 'Number of Bedrooms + 1' or 'Number of Occupants'. Table 2 provides calculated airflow values to the nearest 5 CFM.
| House Sq. Ft. | Number of Bedrooms | |||||
|---|---|---|---|---|---|---|
| 2 | 3 | 4 | 5 | 6 | 7 | |
| 1000 | 35 | 40 | 50 | 55 | 65 | 70 |
| 1500 | 40 | 45 | 55 | 60 | 70 | 75 |
| 2000 | 45 | 50 | 60 | 65 | 75 | 80 |
| 2500 | 50 | 55 | 65 | 70 | 80 | 85 |
| 3000 | 55 | 60 | 70 | 75 | 85 | 90 |
| 3500 | 60 | 65 | 75 | 80 | 90 | 95 |
| 4000 | 65 | 70 | 80 | 85 | 95 | 100 |
| 4500 | 70 | 75 | 85 | 90 | 100 | 105 |
| 5000 | 75 | 80 | 90 | 95 | 105 | 110 |
Determine Outdoor Air (CFM) Delivery Rate
Measure the outdoor air flow (CFM) through the duct bringing in only outdoor air. Use the measured CFM Delivered along with the required CFM to determine the Cycle Time per hour setting from Table 3. For example, if the ventilator provides 120 CFM and the requirement is 70 CFM, set the time to 35 minutes.
| CFM Delivered | CFM Required | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 | |
| 60 | 20 | 30 | 40 | 50 | 60 | |||||
| 80 | 15 | 25 | 30 | 40 | 45 | 55 | 60 | |||
| 100 | 15 | 20 | 25 | 30 | 35 | 40 | 50 | 55 | 60 | |
| 120 | 15 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 | 55 |
| 140 | 15 | 15 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
| 160 | 15 | 15 | 15 | 20 | 25 | 25 | 30 | 35 | 40 | 45 |
| 180 | 15 | 15 | 15 | 20 | 20 | 25 | 30 | 30 | 35 | 40 |
| 200 | 15 | 15 | 15 | 15 | 20 | 25 | 25 | 30 | 30 | 35 |
| 220 | 15 | 15 | 15 | 15 | 20 | 20 | 20 | 25 | 30 | 30 |
System Set-Up & Checkout
Follow these steps for initial setup:
- Check all wiring connections.
- Ensure the wire access cover is securely attached to the on-board control.
- Plug in the unit and turn the power switch ON. The on-board control screen should display 'OFF'.
Note: The first button press on the control may only activate the backlight; a second press is needed to engage a function.
Installer Set-up Menu: Press and hold the MODE button for 3 seconds to enter the Installer Set-up Menu. Use the UP/DOWN arrows to select options and MODE to advance. All options must be scrolled through to exit. Upon completion, 'DONE' will blink for 3 seconds before returning to the 'OFF' screen.
Control Options:
- Model 76 Remote Control Option: If using the on-board control, keep this feature DISABLED. If using the Model 76 Remote Control for humidity settings, set this feature to ENABLED.
- On-Board Ventilation Control: For time-based ventilation without outdoor temperature restrictions, press MODE at the 'VENT TIMED' screen to access ventilation time selection. For ventilation with outdoor temperature restrictions, use the UP arrow to select 'VENT AUTO -B', then UP/DOWN arrows for modes B, C, or D, and finally MODE to proceed to ventilation time selection.
- Vent-Auto-B: Ventilation is prevented if outdoor temperature exceeds 105°F.
- Vent-Auto-C: Ventilation is prevented if outdoor temperature exceeds 100°F.
- Vent-Auto-D: Ventilation is prevented if outdoor temperature exceeds 95°F.
- External Ventilation Control Option: With 'External Control' set to DISABLED, ventilation settings are managed by the on-board control. With 'External Control' set to ENABLED, an external control (like a thermostat) can manage ventilation. The Remote Control option is unavailable when External Control is enabled.
DEH W/AC (Dehumidify with Air Conditioning)
Select ENABLED and press MODE to allow the ventilator to dehumidify during active air conditioning. Select DISABLED and press MODE to prevent dehumidification when the air conditioning is running.
RH Offset
An offset can be applied to the on-board humidity reading to align it with other home humidity measuring devices. Use the UP/DOWN arrows to select an offset from -5% to 5%. Press MODE to exit the installer set-up screens.
Installer Test Mode
This mode tests all wired components. If the unit is not already OFF, press the ON/OFF button to turn it off. Then, press and hold both the MODE and ON/OFF buttons for 3 seconds. The blower will start, the vent damper will open, and the display will show relevant information (e.g., 'AIR SAMPLING'). After three minutes, the compressor will start, and the display will change to 'DEHUMIDIFYING'. After one minute of compressor operation, all outputs will turn off, and 'DONE' will blink for 3 seconds before returning to the 'OFF' screen. The test mode lasts for four minutes; pressing ON/OFF during the test will exit the mode.
Start Up and Sequence of Operation
Turn the ON/OFF switch ON. The first press of any button activates the backlight; a second press is required for function. The display shows the humidity control setting, adjustable via UP/DOWN buttons (1 is less dry, 7 is more dry). The ventilator activates the Vent Damper upon the first call for heating (W) or cooling (Y) from the HVAC system, displaying 'VENTILATING'. For the first five minutes, it measures incoming air temperature. If within limits, it continues as long as the equipment calls or the set ventilation time is met within the hour. If the time is not met, the damper opens at the end of the hour to ensure compliance.
If outdoor air temperature exceeds the high limit, ventilation is skipped for that hour but added to a subsequent four-hour cycle to meet the total requirement. Air temperature is checked hourly. At the end of each four-hour cycle, the ventilator runs for at least one hour, regardless of limits, to ensure the minimum hourly requirement is met. If the requirement is still not met, it's added to the next cycle until the 24-hour period is complete. If the ventilation requirement cannot be bypassed by limits, the ventilator will activate to meet it.
When an external control is wired, ventilation occurs only when a circuit is completed between the DH terminals. The external control dictates ventilation timing. Dehumidification is controlled as described, even with external ventilation control.
When the ventilator is active, it measures the incoming air's dew point. If it exceeds the set point, the compressor activates for dehumidification. The compressor runs for a minimum of three minutes and must be off for at least three minutes. 'DEHUMIDIFYING' displays during operation. If the ventilator is active with a cooling input (Y), the compressor only runs if the DEH W/AC feature is enabled.
Humidity Control Setting Note
The humidity control setting corresponds to a dew point value, which is a more accurate measure for humidity control than %RH. Starting with a setting of 2 or 3 is recommended, adjusting as needed. Higher settings increase compressor run time. Table 4 relates humidity control settings to dew point and approximate resulting indoor RH levels at various temperatures.
| Humidity Control Setting | Corresponding Dew Point | Resulting Indoor RH Level at Various Indoor Temperatures* | ||
|---|---|---|---|---|
| 72°F | 75°F | 78°F | ||
| 1 | 65°F | 78% | 70% | 64% |
| 2 (initial) | 60°F | 65% | 59% | 54% |
| 3 (initial) | 56°F | 57% | 51% | 46% |
| 4 | 52°F | 49% | 44% | 40% |
| 5 | 48°F | 42% | 38% | 35% |
| 6 | 44°F | 36% | 33% | 30% |
| 7 | 40°F | 31% | 28% | 26% |
*Resultant indoor RH levels do not account for internal humidity sources like cooking, showering, etc.
Adjusting Ventilation Time After Initial Set Up (Using On-Board Control)
1. Press the UP or DOWN button to access the humidity control setting screen.
2. Press the MODE button to toggle to the VENT TIME setting.
3. Press the UP or DOWN button to adjust the ventilation time (minutes). After adjustment, the screen will return to the home screen automatically after three seconds.
Maintenance
Clean or Replace the Air Filter
The air filter should be checked and cleaned every 6 months. A 'CLEAN FILTER' service reminder will appear on the on-board control screen. To clear the message, press the UP and DOWN buttons simultaneously for 3 seconds.
Filter Cleaning Procedure:
- Turn the ON/OFF switch OFF.
- Remove the filter access door from either side of the ventilator.
- Slide the filter out of the ventilator.
- Flush the filter with warm water and a mild detergent solution.
- Shake off excess water.
- Replace the filter, ensuring it is secured in both filter rails.
- Replace the filter access door.
- Turn the ON/OFF switch ON.
- Press the UP and DOWN buttons simultaneously for 3 seconds to clear the service message.
Check the Drain
The drain system should be checked annually for blockages or air locks. If the unit is not draining properly, have it inspected by a qualified service professional.
CAUTION: Do not use spray solvents or cleaners on or near the inlet side of the ventilator. If desired, apply cleaner to a cloth and use it to clean the cabinet.
Troubleshooting
Technical Support is available Monday through Friday, 7:00 a.m. to 5:00 p.m. CST, at (800) 334-6011. Consult the following guides to identify and correct system faults. Contact Technical Support before replacing the unit or any components.
Diagnostic Codes
When an error occurs, the Diagnostic Code and 'SERVICE REQUIRED' will be displayed on the control screen.
| Diagnostic Code | Failure Mode | Action | Reset |
|---|---|---|---|
| E1 | Internal Humidity or Temperature Sensor Open or Shorted | 1. Check sensor board and control board connections. 2. If connection is okay, replace sensor board (Part No. 5460). | Cycle Power |
| E2 | High Refrigeration Pressure | 1. Verify fan operation, backflow damper movement, and absence of ductwork blockage. 2. If fault persists, call Technical Support. | Cycle Power |
| E4 | Loss of Capacity | 1. Cycle power to clear the code. 2. Set humidity to 1 and Vent Time to 60. 3. Enter diagnostic display (hold UP and MODE for 3 seconds). Check air temperature, relative humidity, and Frost Sensor temperature. 4. If Frost Sensor temperature is significantly lower than air temperature, replace Frost Sensor (Part No. 5455). 5. If sensor is OK, set humidity to 7 to run compressor for 15 minutes and recheck sensor temperatures. Frost Sensor temp should be 5°F to 20°F difference from air temp. 6. Call Technical Support if Frost Sensor temperature does not decrease. | Cycle Power |
| E5 | High Temperature Thermistor Failure | 1. Access electrical service box. 2. Verify 'Hi-Temp' sensor connector seating. 3. Cycle power; if code persists, replace sensor (Part No. 5456). | Cycle Power |
| E6 | Low Temperature Thermistor Failure | 1. Access electrical service box. 2. Verify 'Frost' sensor connector seating. 3. Cycle power; if code persists, replace sensor (Part No. 5455). | Cycle Power |
| E7 | Float Switch Open | 1. Empty condensate pan. 2. Check float switch connection. 3. If not using a float switch, verify jumper is installed. 4. If problem persists, replace float switch. | Self-Correcting |
| E8 | Inlet Air Too Hot or Cold to Dehumidify | Informational display. No moisture removal occurs if air is below 50°F or above 104°F. Check ductwork sealing. | Self-Correcting |
Troubleshooting Guide
| Symptom | Possible Reason | Troubleshooting Procedure |
|---|---|---|
| Ventilator does not turn on/run. | No power to unit. |
|
| Ventilator blower is running but with little or no airflow. | Pressure drop across ventilator is higher than 0.4"w.c. |
|
| Ventilator blower is running but compressor is not. | Float switch open. |
|
| Coil frosting. |
|
|
| Inlet air temperature is outside of the 50°F - 104°F range or the dew point is below 40°F and there is a demand for dehumidification. | Verify all ductwork is properly sealed. | |
| The ventilation damper does not open when the HVAC fan is active. | Cycle time has been met. | The damper will not open if the Ventilation Time has already been met. |
| Ventilator is not draining properly. | Drain line blocked or unit not level. |
|
| The HVAC fan turns on unexpectedly. | Ventilator is sampling or ventilation in progress. | The ventilator may turn on the HVAC fan during air sampling or as needed to meet ventilation time. |
| Ventilator is producing hot air. | Normal function. | Air is reheated across the condenser coil, causing a temperature rise between inlet and outlet. |
| Display shows "OFF" even when the ON/OFF button is pushed. | A manual override switch has been installed and has turned the unit OFF. | Turn the manual override switch OFF. |
Service Parts
Diagram and list of available service parts:
| No. | Part Description | Part No. |
|---|---|---|
| 1 | Filter, 10" x 12" x 1" EZK | 5443 |
| 2 | Internal Control Board | 5444 |
| 3 | User Interface Assembly | 5564 |
| 4 | Wiring Access Door | 5446 |
| 5 | Hole Cover, UI Ctrl | 5447 |
| 6 | Door, Filter Access | 5448 |
| 7 | Outlet Duct Panel | 5449 |
| 8 | Backflow Damper, 10" | 5450 |
| 9 | Inlet Duct Panel | 5451 |
| 10 | Cover, Outlet | 5452 |
| 11 | Model 8191 Fan | 5453 |
| Model 8192 Fan | 5467 | |
| 12 | Wire Harness, Power | 5454 |
| 13 | Sensor, Low Temperature | 5455 |
| 14 | Sensor, High Temperature | 5456 |
| 15 | Leveling Foot | 5457 |
| 16 | Capacitor, 45MFD, 370VAC | 5458 |
| 17 | Model 8191 Capacitor, 8MFD, 450VAC | 5459 |
| Model 8192 Capacitor, 12MFD, 450VAC | 5468 | |
| 18 | RH Sensor | 5460 |
| 19 | Drain Tube + Fittings | 5461 |
