J.P. Instruments EDM 760 Fuel Flow Installation Manual - Manual (Page 5)

J.P.Instruments Fuel Flow Installation Manual
Report # 760
for EDM-760 temperature indicating system with Fuel Flow Option Appendix - A
Page Page 5 of 14 Rev NC :
Date 07/20/99
The flow transducer must be mounted so the wires exiting the transducer are pointing up.
Before connecting any hoses, thoroughly clean them and insure they are free of any loose material. High
air pressure my be used, However, do not allow high air pressure to pass through the flow
transducer.
4…. Route the (Optional) External Warning Control Line:
The wire from pin 15 on the J-1 (D-SUB 25) Connector can be connected to an external warning light or
buzzer. This wire grounds when the display flashing a warning is on. The current in this line must be limited
to 2/10 of an amp maximum. Exceeding this limit will damage the unit. If this feature is not used leave this
line open. Tie wrap this wire so it does not obstruct the freedom of travel- controls.
5…. Route the Fuel Flow Transducer Wires: (The following section is an excerpt from report
#103 Installation Manual, STC 2586NM)
Route the thermocouple and fuel flow wires from the probes through the firewall using fireproof
rubber grommets and flame retarding silicone. Use an existing hole if possible. Following the
existing wiring harness and connect to the indicator marking each lead with the cylinder number.
All wires must be routed away from high temperature areas (exhaust stacks, turbochargers,
etc.). Secure Probe leads to a convenient location on the engine approximately 8 to 12 inches
from the probe, being sure there is sufficient slack to absorb engine torque. It is essential in
routing the probe and fuel flow transducer wires not be allowed to touch metal parts of the
air-frame or engine since abrasion will destroy this wire. Connect wires in accordance with dwg.
700744, page 12
6….. System Checkout: Check instrument operation as follows:
1. Turn the aircraft master switch on (engine off) and set the toggle switch to Fuel Flow . Tap the step
switch until 0 GPH is displayed. Turn the boost pump on for a few seconds. The display should indicate
3 to 8 GPH.. A problem at this step could be caused by poor connections on the red or black power and
ground leads.
2. Set the instrument toggle switch to "Fuel Flow" and check for a digital fuel flow reading of "00 GPH"
indicates the fuel flow is too low to register. A reading of “ ---GPH “ dashes indicate no fuel flow
transducer signals. A problem at this step could be caused by a poor connection or crossed flow
transducer wires.
3. With the engine running, check the "FLOW" Display Mode to read properly. If there is a problem at this
point Refer to EDM-700 Fuel Flow Option Supplement Rev C. Section 4 for troubleshooting
information.
4. After running the engine, check the fuel hoses, transducers and fittings for leaks.