Electronics International MVP-50P - Manual (Page 38)

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2.14 Install the EI P-300C Fuel Level Probes (OEM or Expermintal Only):
Install the P-300C (Capacitive) Fuel Level Probes in accordance with the aircraft manufacturer’s instructions.
2.15 Install the EI P-300M Fuel Level Sender:
The MVP-50 system can interface with an aircraft’s existing Resistive Fuel Sensors via the RFLM-4 or these
resistive fuel level sensors can be replaced with the P-300M (Magnetic Float) Fuel Level Sender. The signal
produced by the P-300M Sender is a linear voltage output designed to work with the MVP-50 system.
The P-300M’s float arm and travel must match the aircraft’s existing sender’s arm and travel. Due to the lack
of information from aircraft manufacturers, the existing sender may need to be removed from the aircraft and
sent to Electronics International. In this way the P-300M’s float arm and travel can be matched with the
aircraft’s existing sender. Contact Electronics International for further information.
The P-300M has the same bolt pattern as resistive fuel senders. The P-300M requires three wires to interface
to the EDC (resistive senders only use one wire).
Note: Note: Note: Note: Note: Calibrating the MVP-50P to a fuel tank can compensate for nonlinearity in the tank’s shape and
nonlinearity in the resistive fuel level sensor. The MVP cannot correct for inconsistent or non-repeatable
signals from resistive fuel level senders. Unfortunately, many older resistive fuel level senders (and in some
cases, newer resistive senders) exhibit some of the following problems:
- Variation in the wiper-to-element resistance (CRV).
- Stick slip problems with bearings and wiper-to-element contact.
- Windup causing jumps in readings.
- Weak wiper tension.
- Loose or worn bearings, causing fluctuations in tension and resistance.
- Worn out wiper.
- Corroded wiper.
- Corroded or worn element.
- Build up of varnish on the wiper and element.
- Water logged floats.
If you find inconsistent or inaccurate fuel level readings (due to a defective resistive fuel level sender), you
must have the sender replaced. Inaccurate readings can lead to a dangerous situation. The MVP-50P depends
on the fuel level sender for accurate fuel level information. Read the “Important Notice” in the MVP Operat-
ing Instructions.
The P-300M is a float type fuel level sender that uses a magnet and pickup device to detect the float position
and produce the signal for the MVP-50 system. The P-300M has no wiper or resistive element and there is no
tension on the bearing surfaces. It is not subject to the many problems associated with resistive type senders.
The P-300M has nothing to wear out or affect inaccurate fuel level readings. Also, the P-300M does not
require electricity to flow through an element and wiper saturated in fuel, as is the case with resistive senders.