Garmin G3X Installation Manual page 272

21.3.11 Fuel Flow
Electronics International FT-60 (Red Cube) - This sensor is applicable to all engines. Refer to the
Electronics International FT-60 Flow Transducer (Red Cube) document # 1030032 for installation
guidance.
General Installation Guidance (Floscan Series 200) – This sensor is applicable to all engines. The
below is taken from the Floscan Series 200 Flow Transducer Application Notes:
1. The inlet and outlet ports in series 200 flow transducers have ¼" NPT threads. Use only ¼" NPT
hose or pipe fittings to match. When assembling fittings into the inlet and outlet ports, DO NOT
EXCEED a torque of 15 ft. lbs. (180 inch lbs.), or screw the fittings in more than 2 full turns past
hand tight WHICHEVER HAPPENS FIRST. Floscan Instrument Co., Inc. will not be responsible
for cracked castings caused by failure to use ¼" NPT fittings, over-torquing the fittings, or assem-
bling them beyond the specified depth.
2. A screen or filter should be installed upstream of the flow transducer to screen out debris which
could affect rotor movement or settle in the V-bearings. As turbulence upstream of the transducer
affects its performance, there should be a reasonable length of straight line between the transducer
inlet and the first valve, elbow, or other turbulence producing device.
3. Install the flow transducer with wire leads pointed UP to vent bubbles and ensure that the rotor is
totally immersed in liquid. For maximum accuracy at low flow rates, the transducer should be
mounted on a horizontal surface.
Some additional mounting considerations should be noted as follows:
1. When installing the NPT fittings into the transducer, use fuel lube such as EZ TURN © or an
equivalent thread sealer. Teflon tape should NEVER by used in a fuel system.
2. To minimize inaccuracies caused by turbulence in the fuel flow, the sensor should be mounted with
approximately 5-6" of straight tubing before and after the sensor. If special circumstances exist
that prevent an extended length of straight tubing before and after the sensor, then a gently curved
hose may be acceptable. 45 degree or 90 degree elbow fittings should NOT be used immediately
before or after the sensor.
3. Specific sensor mounting location is left to the builder. Ideally, the sensor should be placed prior
to the fuel distribution device (carburetor or fuel injection distribution device).
4. On a Continental fuel injected engine, the transducer must be located between the metering unit
and the flow divider valve.
5. Sensor wires should be connected to the appropriate inputs on the GEA 24/GSU 73 as referenced
in the G3X interconnects in Section 27 through Section 30.
For engines with a fuel return line, a second flow sensor must be used to measure the quantity of unused
fuel that is returned from the engine to the fuel tank. Connect the return fuel flow sensor to the GEA 24/
GSU 73 FUEL FLOW 2 input (see
difference between the main (supply) fuel flow and secondary (return) fuel flow measurements.
190-01115-01
Rev. AA
Figure 27-2.1). The value displayed on the fuel flow gauge will be the
G3X/G3X Touch Installation Manual - Engine/Airframe Sensor Installation
Page 21-28