Aprilaire Ventilation Control System

STEP 1: UNPACK THE VENTILATION CONTROLLER CARTON

Make sure all components are present. (See Figure 1)

1. Model 8120 Ventilation Controller ('Controller')
2. Outdoor Temperature Sensor
3. "TIME ONLY" Resistor

Figure 1. Carton Contents: Depicts the Aprilaire Ventilation Controller, an Outdoor Temperature Sensor, and a "TIME ONLY" Resistor labeled C.

STEP 2: SET THE CYCLE TIME INTERVAL

• Remove the knob by pulling it straight out from the Controller. Remove the cover by grabbing along the top and bottom edges of the cover and pulling straight out from the base.
• The jumper on the 5-pin header determines the cycle time interval. The interval can be 1, 2, 3, or 4 hours. (Default setting is 1 hour.) Refer to Figure 2.
• Move the jumper to the desired interval. The jumper can be removed by pulling it straight out from the header pins.

Figure 2. Cycle Time: Shows a 5-pin header with a jumper. Labels indicate "CYCLE TIME 1 HR 3 HR" and "CYCLE TIME 2 HR 4 HR". The diagram illustrates how to set the cycle time by moving the jumper.

STEP 3: DETERMINE LOCATION OF VENTILATION CONTROLLER AND MOUNT IT.

The Controller must be mounted in the return duct. For proper operation, the Controller must be at least 6 inches upstream from the following:

• Fresh Air Intake Ductwork.
• Humidifier
• Humidifier Bypass Ductwork

In installations where it's difficult to mount the Controller 6" upstream from the fresh air intake (when using a mixing box with flex duct returns for example), mount the Controller as close to the main return duct as possible. Refer to Figure 3.

After the location for the Controller is selected, use the perforated Ventilation Controller Template (attached to these instructions) to mark the duct opening, and then cut it. Mount the Controller in the duct opening and make sure the Controller is sealed tightly to the duct.

Figure 3. Typical Installations: Illustrates mounting the Controller at least 6" upstream from the fresh air intake, inside or close to the return duct. It shows the Controller connected to the return duct, with the fresh air intake, humidifier, and bypass connections nearby. It also shows the Aprilaire Air Cleaner and Furnace/Supply Duct.

STEP 4: CHOOSE MODE OF OPERATION

There are three modes of operation:

1. By connecting the Outdoor Temperature Sensor (see Figure 4), the Controller will use Outdoor Temperature and Indoor Humidity, along with the user-adjustable timer settings, to determine when to ventilate. This is the recommended installation as it uses all the advanced features of the Controller. For this installation, go to STEP 5.
2. By shorting the two Outdoor Temperature Sensor terminals with a standard 20-gauge wire (not provided), the Controller will disregard the temperature setting and base the ventilation on the indoor relative humidity and the user-adjustable timer settings.
3. By connecting the "TIME ONLY" resistor (provided) across the Outdoor Temperature Sensor terminals, the Controller will ignore outdoor temperature and indoor relative humidity and base ventilation simply on the time set by the installer/homeowner.

Refer to Owner's Manual for more details on the operation of the Controller.

Figure 4. Outdoor Temperature Sensor Terminal: Shows the location to insert the temperature sensor, labeled "INSERT TEMP. SENSOR HERE", with terminals for 24VAC and "OUTDOOR TEMPERATURE SENSOR".

STEP 5: LOCATION & WIRING OF OUTDOOR TEMPERATURE SENSOR

• The location of the temperature sensor should be in the Fresh Air Intake Hood (not provided) or in the Intake Duct, no more than 3 feet from the outside wall.
• The Outdoor Temperature Sensor is not affected by wire length. Do not route the wire alongside wires carrying high voltage (120 VAC or greater) as interference may occur.
• Strip wire 1/4 inches, and insert the wires from the sensor into the terminals labeled "Outdoor Temperature Sensor" on the Ventilation Controller. See Figure 5 for terminal locations.

STEP 6: WIRE VENTILATION CONTROLLER TO HVAC EQUIPMENT

NOTE: When installing the Ventilation Controller in a system with a power-stealing thermostat, it is recommended that load resistors be placed across Y and C terminals as well as W and C terminals.

CAUTION - Improper wiring to the HVAC equipment could cause damage to the Ventilation Controller and/or the HVAC equipment.

• Route wire from the R, C, W, and GHVAC terminals on the Ventilation Controller to the corresponding terminals on the furnace/heat pump control board. See Figure 5 for the terminal locations.
• Route a wire from the GSTAT terminal on the Ventilation Controller to nearby the furnace/heat pump control board but do not connect it. Instead, on the furnace/heat pump control board, disconnect the G wire that comes from the thermostat, and use a wire nut (not provided) to connect the G wire from the thermostat to the GSTAT wire from the Ventilation Controller. NOTE: The only wire connected to the G terminal on the furnace/heat pump control board should be the GHVAC wire from the Ventilation Controller.

Figure 5. Wiring Diagram: Shows the Ventilation Controller's terminal block with connections for R, C, W, GHVAC, GSTAT, 24VAC, and Outdoor Temperature Sensor. It illustrates wiring to the HVAC equipment and the Aprilaire Model 4010 24 VAC Transformer and Model 6506 NC Damper.

STEP 7: INSTALL AND WIRE DAMPER

The Aprilaire Normally Closed Damper (Model 6506) needs to be installed into the Fresh Air Intake. It should be wired in series with a continually energized 24 VAC transformer Model 4010 and connected to the terminals labeled "A/A" of the Ventilation Controller. (See Figure 5.)

When done with all wiring, put the cover back on the Controller and slide the knob onto the shaft.

In addition to these instructions, follow all installation instructions that are supplied with the damper.

STEP 8: SETTING THE VENTILATION TIME

The knob on the exterior of the Controller (see Figure 6) is used to set the ventilation time within the cycle time interval you set in STEP 2.

The knob settings range from "OFF" which is all the way counter-clockwise, to "TEST" which is all the way clockwise. Within those two extreme settings, the ventilation can be set from 0 to 60 minutes of ventilation time. For example: if you set the cycle time to 1 hour and the ventilation time knob to 20 minutes, you will get 20 minutes of ventilation every hour. See Owner's Manual for more details on operation.

Figure 6. Ventilation Time: Shows the control knob with markings for "OFF", "TEST", and numerical settings from 0 to 60 minutes, in 15-minute increments.

STEP 9: SYSTEM CHECKOUT

1. For system test, be sure that 24 VAC is applied in series with the Aprilaire® Normally Closed Damper (Model 6506) and connected to the "A/A" terminals on the Ventilation Controller.
2. Check the wiring to the Furnace/Heat Pump described in STEP 6.
3. Rotate the control knob clockwise to the "TEST" position.
4. If all is set up properly, the blower will turn on and the damper will open. The blower will remain on and the damper will remain open for 1 minute or until the knob is removed from the test position, whichever happens first.
5. If the damper or blower does not activate in TEST Mode, refer to the Troubleshooting Guide.
6. Rotate the knob to the desired ventilation setting. Note: do not leave the knob in the "TEST" position as the Controller will not operate after the 1 minute test sequence is over.

INSTALLATION TEMPLATE: A perforated template is provided for marking duct openings.

WARNING

Sharp edges may cause serious injury from cuts. Use care when cutting plenum openings and handling ductwork.

CAUTION

1. Do not mount the Ventilation Controller on the supply plenum or duct. The unit will not withstand the supply temperatures.
2. When installing the Ventilation Controller on downflow furnaces, ensure blower continues to run after a heat call is satisfied to eliminate high temperatures from damaging the Ventilation Controller.
3. Do not mount the Ventilation Controller downstream of a fresh air intake, humidifier or bypass outlet. False humidity conditions will cause the Ventilation Controller to operate incorrectly.

APRILAIRE DAMPER

Diagram Description: Shows the Aprilaire Damper with components labeled: BRACKET, MOTOR, INDICATOR LABEL, STOP SCREW. The diagram notes "(Shown with Plastic Cover Removed)".

INSTALLATION PROCEDURE

1. Step 1: Install damper with crimped end downstream.
2. Step 2: Slide damper over end of crimped duct and secure to duct with 1/2 long sheet metal screws (not included).
3. Step 3: The fresh air intake ductwork and damper must be fully insulated and all seams must be sealed to prevent condensation from forming.

NOTE: Support all duct work in accordance with local code or SMACNA standards.

Research Products Corporation
P.O. BOX 1467 MADISON, WI 53701-1467
Call 608/257-8801 FAX 608/257-4357
Products For Better Indoor Air Quality™

I. PRINCIPLE OF OPERATION

With your purchase of the Aprilaire® Ventilation Controller, you have invested in an intelligent way of providing fresh air to your home. Working in conjunction with an Aprilaire® Damper, the Ventilation Controller makes decisions regarding when - and how long - to ventilate. It does this through continuous monitoring of indoor relative humidity, outdoor temperature, and user-adjusted timer settings.

Indoor relative humidity is monitored to help prevent high humidity conditions inside your home. The Aprilaire® Ventilation Controller will not open the damper to the outside air if there is a chance of raising the humidity inside the house to high levels. The Aprilaire® Ventilation Controller is designed to prevent indoor relative humidity levels from increasing beyond 60% due to ventilation.

If the outdoor air temperature is below 0°F or above 100°F, the motorized normally-closed damper to the outside will not be opened. This feature can be disabled at installation if the installer chooses not to use outdoor air temperature as a parameter.

II. OPERATING INSTRUCTIONS

Your Ventilation Controller is installed in the return duct of your furnace or heat pump. There are two settings that are adjustable: the cycle time and the ventilation time within cycle. Here's how this works: if you set the cycle time to 1 hour and the ventilation time knob to 20 minutes, you will get 20 minutes of ventilation every hour. It is important to understand that the ventilation requirement - 20 minutes per hour in this example - may be satisfied by a heating, cooling, or fan call initiated by your thermostat, or from a fan call initiated by the Ventilation Controller itself. The following steps explain how to adjust these settings.

III. OUTDOOR TEMPERATURE & INDOOR HUMIDITY CONTROL LIMITS

In a standard installation, your Aprilaire Ventilation Controller will use measurements of Outdoor Temperature and Indoor Humidity, along with the user-adjustable timer settings, to determine when to ventilate. Outdoor Temperature is measured with a sensor placed at the inlet of the fresh air intake duct. Indoor Humidity is measured in the return duct with a sensor built into the Controller. In conjunction with the timer settings, the Controller then operates according to the temperature and humidity control limits shown in Figure 3 below.

Figure 3 – Model 8120 Operating Limits: This graph plots Indoor Relative Humidity (%) on the Y-axis against Outdoor Temperature (°F) on the X-axis. It shows three sections:

• SECTION A: Controller will not ventilate due to temperature extremes (e.g., below 0°F or above 100°F Outdoor Temp, or above 55% Indoor Humidity).
• SECTION B: Controller will ventilate according to timer settings (e.g., between 50°F and 100°F Outdoor Temp, and below 55% Indoor Humidity).
• SECTION C: Controller will ventilate only when heating is on according to the timer settings (e.g., between 0°F and 50°F Outdoor Temp, and below 55% Indoor Humidity).