AirScape Engineer's Blog

Recently we have been using our new and improved sound testing chamber to make sound comparison videos of our different models. The shooting of these videos reminded us that the set up of the ducted models will make a significant difference in the CFM and noise levels. Basically, improper installation will decrease the unit CFM and increase the amount of noise. Some numbers for comparison:

AirScape 4.5 improper installation -  high 59 dBA / low 50 dBA

AirScape 4.5 proper installation -  high 55 dBA /low 46 dBA ……A 4 dBA difference!

The photo above shows the correct install dimensions for the 4.5 WHF. You will notice that we have a nice even bend and the ductwork is fully extended (Note that we used an extra length of the provided chain to help support the bend). It is important to maintain the 20″ diameter of the duct through the 90 degree bend. This will ensure that you get unrestricted airflow through the duct and will help disrupt the sound waves. You also want to make sure the duct and fan are fully extended from the 90 degree bend. This moves the fan to the furthest point from the grill opening, thus decreasing the decibel level.

Airscape 2.5/2.5e installation: The install dimensions for the AirScape 2.5/2.5e are very similar. The duct should be 21″ from the attic floor. It should extend 44″ from the 90 degree bend to the fan (you may be able to extend it to 48″ if the bend is supported as shown in the photo above). The top of the fan should be 44″ from the attic floor.

The newest version of our control board has a master override or interlock. The interlock, which is now required by some building codes, effectively disables the WHF by closing the damper doors and turning off the fans. It is often used in conjunction with smoke detectors or mechanical systems located in the attic. The idea is that if the furnace turns on or the smoke detector goes off the WHF will shut down. This could slow down the spread of a fire or save $$$ if the furnace was accidentally turned on.

The interlock is integrated into our 24v digital controls on V4 of our control board. To use the interlock simply remove the two-pin shunt and run low voltage wire from the interlock screw terminals to the relay on the device that will disable the WHF. To activate the interlock the relay should interrupt the 24v current. Do not wire 120v to the interlock.

When activated a solid red LED will illuminate on the WHF control board. The fans will turn off and the damper doors will close. Once the interlock is disengaged, the LED will go out. The WHF can be restarted by flipping the wall switch off and on again or by using your remote.

When you call in with a tech support issue we will want to know which version of our control board is controlling your unit. This is important because it will help us properly diagnose what is going on with your WHF. In most cases we can determine the control board version if you give us the model information for your AirScape. The model is listed on a sticker found on the unit (near the junction box on the 1.7, 2.5, 4.5 and on the damper door of the 1.0). Occasionally the model sticker isn’t enough. If you are already going into the attic to write down the model information you might as well take a look at the control board as well.

The control board has had several different incarnations over the years. Please take a look at the photos below and identify your control board before you call tech support.

My control board looks most like: 1, 2, 3, 4, 5 or 6 (Differences between 3 and 4 circled in red)

1 2

3 4

56

NOTE: The following instructions do not apply to the Kohilo 2.8

We often get asked how to use a timer with our whole house fans. The short answer is to purchase the optional wireless remote which has a built in timer. But for people who prefer a wall switch there is a solution for you. You can wire a mechanical turn dial timer to operate your WHF. We recommend a mechanical timer because most digital timers require 110v. Our controls are 24v and hooking up 110v would damage the AirScape control board. We also want the process to be a manual one so that you remember to open a window. The following shows two ways to wire a timer with your AirScape WHF:

OPTION 1: TIMER AND AIRSCAPE WALL SWITCH

OPERATION:

ON – Wall switch in on position, turn timer to desired time, chose fan speed

OFF – Switch wall switch to OFF or timer expires

OPTION 2: TIMER AND CUSTOMER SUPPLIED SINGLE POLE SWITCH

OPERATION:

ON – Turn timer to desired time, choose fan speed

OFF – Timer expires

Not only does the AirScape 2.5e have phenomenally low energy use, the user can also select up to 5 different CFM settings. The 2.5e fan motor has inputs which we program at different CFM. From the factory it is set for a low speed of 1512 CFM at 42 watts and a high speed of 2536 CFM at 196 watts. Now let’s say that the factory low speed setting does not provide enough airflow to properly cool your home over night. The fan speed settings can easily be adjusted for more airflow. For example, you could change the low speed from 1512 CFM to 2080 CFM. At the same time you could also adjust the high speed setting so that the fan will move 2604 CFM on high (see example #2). This is as simple as moving the low and high speed wires on the 2.5e fan control board (located on the fan housing) to different connections. The fan speed adjustment is described below:

1. Turn your 2.5 e off. Unplug the fan power cord and turn off power to the damper box by unplugging it or switching the circuit breaker off if hardwired.
2. Remove the fan junction box cover (located on the fan housing).
3. Move the low and high speed wires to different taps to adjust fan speed (see photos).
4. Plug in the fan power cord and turn the damper box power back on.
5. The unit is now ready to operate at the new CFM settings.