The HTAF 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 HTAF will pump up the header tank
for a short time period, then automatically shut the fuel pump off. The HTAF is
normally used with a very reliable optical fuel level sensor (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, the HTAF can be set up so the pilot may
manually activate the timed pumping.
The HTAF can be
operated in one of four pre-programmed pumping times. 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. The system can be powered by +12V or +24V
electrical systems.
Model: HTAF vs HTAF2
HTAF
Operation:
Manually or
One Sensor Operation (Header Tank Low Fuel)
Pumping Period:
4
selectable pumping periods
HTAF2
Operation:
Manually or
One Sensor Operation (Header Tank Low Fuel) or Two Sensors Operation (Header
Tank, Low Fuel and Fuel Full)
Pumping period:
Selectable
from 0 to 10minutes
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 TANK
If the user is not
able to install a fuel sensor in the header fuel tank, the HTAF can be set up so
the pilot may manually activate the HTAF. This can be accomplished with a
normally open switch (NO) connected between terminals 2 and 11. Pressing this
switch simulates a low fuel condition starting the HTAF. This switch can be
installed on the instrument panel. (NOTE: because the HTAF was designed for a
fuel sensor, and it utilizes fuel slosh damping, the user may have to press this
switch for several seconds before the pumping starts.
SELECTING A PUMPING TIME
The
HTAF can be operated in one of the four possible pre-programmed pumping times.
Select one of these time periods below and wire the HTAF according to the
manual diagram.
1 MINUTE Pump Time
PUMPTIME0, HTAF Terminal 3, Connect to
battery common.
PUMPTIME1, HTAF Terminal 4, Connect to
battery common.
2 MINUTE Pump Time
PUMPTIME 0, HTAF Terminal 3, No
connection (OPEN)
PUMPTIME 1, HTAF Terminal 4, Connect to
battery common.
3 MINUTE Pump Time
PUMPTIME 0, HTAF Terminal 3, Connect to
battery common.
PUMPTIME 1, HTAF Terminal 4, No
connection (OPEN)
4 MINUTE Pump Time
PUMPTIME 0, HTAF Terminal 3, No
connection (OPEN)
PUMPTIME 1, HTAF Terminal 4, No
connection (OPEN)
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.
Can you use a Pillar Point Fuel Sensor?
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
output sensors.
SPECIFICATIONS:
Input Power: (12 to 14Vdc) or (24Vdc
to 28V), 0.1A
max.
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
pumps.)
