* OPERATE MANUALLY, WITH ONE OR WITH TWO FUEL SENSORS
* MANUAL OPERATION - USER SELECTABLE PUMP TIMES (0-10 MINUTES)
* NEW DESIGN MINIMIZES WIRING
* RELIABLE OPTICAL FUEL SENSOR (OPTIONAL)
* PUMP-UP COMPLETED SIGNAL
* SLOSHING FUEL WILL NOT AFFECT OPERATION
* MALFUNCTION WARNING INDICATION
The HTAF2 is a “Smart” Header Tank Pump Relay. This device automatically keeps
the aircraft header tank full without over stressing your fuel pump. A low fuel
sensor can be easily mounted in the header tank. When low fuel is detected in
the Header Fuel Tank, the HTAF2 will pump up the header tank for a short time
period, then automatically shut the fuel pump off. The HTAF2 is normally used
with one or two very reliable optical fuel level sensors (optional) that can be
easily installed in the header fuel tank. If the user is not able to install a
fuel sensor in the header fuel tank, or a sight tube area, the HTAF2 can be set
up so the pilot may manually activate the timed pumping.
The HTAF2 pumping time is user selectable from zero to ten minutes. The
unit also has a relay output that can be used for a light to indicate when the
fuel in the header tank is low. The low fuel relay output is damped so
that it does not falsely indicate low fuel in the case of sloshing fuel.
This same relay output is used for a malfunction alarm. If you connect a
light or LED to the relay output, you can see any such malfunction in the
The HTAF2 was
designed for a fuel sensor inputs. It utilizes a fuel slosh damping
technique to eliminate fuel level detection malfunctions. The system can
be powered by +12V or +24V electrical systems.
Model: HTAF vs HTAF2
One Sensor Operation (Header Tank Low Fuel)
selectable pumping periods
One Sensor Operation (Header Tank Low Fuel) or Two Sensors Operation (Header
Tank - Low Fuel and Fuel Full)
from 0 to 10 minutes
ELECTRONICS ENCLOSURE INSTALLATION
The electronics enclosure was designed to mount almost anywhere.
Mounting it near the sensor or fuel pump eliminates the need for running long
wires. Keep the enclosure away from extremely high temperatures, areas of
excessive vibration or where fuel may be spilled.
IF YOU CANNOT INSTALL A FUEL SENSOR IN THE HEADER
the user is not able to install a fuel sensor in the header fuel tank, or is not
able to install it in a fuel sight tube area, the HTAF2 can be set up so the
pilot may manually activate the HTAF2. This can be accomplished with a normally
open push button switch (NO) mounted in the cockpit. Pressing this switch
simulates a low fuel condition starting the HTAF2. The pump will start and
pump for a time period selected by the user.
SELECTING A PUMPING TIME PERIOD
The user can select a pumping time period from 0 to 10 minutes.
USE of OTHER FUEL LEVEL SENSORS
Can you use other fuel level sensors?
YES, if they are compatible with our sensor output. The output should be
an "open collector" or a TTL (0 to +5V) type output. The output must be
high in air, low in fuel. Please read below for 0 to 3.3V outputs.
I already have Pillar Point Fuel Sensors. Can I use them with the HTAF2?
Well, maybe. The Pillar Point sensor has an output that is an open
collector output (BLU wire), but it is not compatible because it has the
opposite output response. The only output that is compatible, is the 0 to
+3.3V output (WHT wire). We have tested it and it does work. This
output is compatible with the APFR and the HTAF. On the HTAF2, only the
"Start Sensor" input will work. You cannot use the Pillar Point sensor for
the "Finish Sensor" input on the HTAF2. Please email us and ask, . . we
are working on a version of the HTAF2 that will work with opposite polarity
Input Power: 12Vdc or 24Vdc, 0.1A
Enclosure: 3.5" x 2.25 x 1.25"
(89mm x 57 x 32mm )
Fuel Sensor Mounting:
The sensor threads are 1/4 NPT. The leads are about 5" long.
Torque: (13.26 in.-lbs. (1.5Nm)) Max.
DO NOT over torque the sensor!
Weight: 3.0oz. (93g), 3.3oz.
(103g) with sensor
Pump & Pump-Down Outputs: 8A max.
(Output can be used to drive another high current relay for higher powered