SafeSpeed™ DPS Fan Interlock
What is it?
The SafeSpeed™ DPS interlock system is a safety feature that adjusts the speed of your AirScape Whole House Fan based on differential pressure. The system monitors the difference in pressure between your house and the outdoors and adjusts the speed of the fan if excessive negative pressure is sensed inside the house. This negative pressure can be the result of forgetting to open windows before operating the whole house fan and can potentially lead to problems such as pulling objectionable odors from crawlspaces.
The SafeSpeed™ system is available for AirScape whole house fans produced after July of 2013 with GEN 2 Controls (not compatible with the Digital Touch Controller or Kohilo whole house fans). If you would like to retrofit the SafeSpeed™ system onto an older whole house fan please give us a call as it may be possible depending on the model and vintage.
How does it work?
The SafeSpeed™ DPS interlock logic is built into the AirScape whole house fan control board and requires the purchase of the optional SafeSpeed kit.
The DPS-SENSE sensor that comes with the kit is mounted in the attic space and connected (wired) to the whole house fan control board. The sensor has 2 ports (connection points) where pressure tubing is connected. One tube senses pressure between the whole house fan and the intake grille and the other senses outdoor pressure.
During whole house fan operation, the sensor monitors the difference between the 2 pressures to determine if the pressure inside the house has become overly negative with respect to the outdoors. If the pressure crosses the alarm threshold, the sensor signals the AirScape fan controller to start reducing the fan speed. The controller reduces the speed of the fan by 1 every 30 seconds until the house pressure is lowered below the alarm threshold. If the fan gets to its minimum speed and the alarm is still active the whole house fan will shut down.
How do I know that SafeSpeed™ protection activated?
First, your whole house fan will be running at a slower speed or will be completely off. Secondly, the web interface will indicate that the SafeSpeed™ protection activated via the "Reduced by Pressure Control" message.
The DPS-SENSE Sensor
Adding the sensor to your installation is simple. Mount it near the whole house fan, connect the included wires to the whole house control board and install the pressure sensing tubes. One tube is installed to sense pressure between the whole house fan and the intake grille and the other tube is run out an eave or attic vent to allow it to sense outdoor pressure.
Can I speed up the fan after opening more windows?
You can continue to control your whole house fan with the hardwired switch or wireless remote control. Pressing any button resets the "Reduced by Pressure Control" message and returns the fan to normal operation.
And don't forget, one of the coolest features of the 2nd Gen Controls is the WHF accessibility over your home network. You can view its status from your desktop computer, smartphone, tablet, etc. It just has to be connected to the same home network that the WHF is plugged into.
Do you have the TSP?
The Temperature Sensor Package allows you to view the attic, outside and space temperatures so you know exactly what your system is doing.
Check out more info on the TSP here.