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How to prevent tiny amounts of back-flow or noisy pulsers from recording to vehicle 000000 on the Service Transactions- Unassigned and Exception Fluid Totals report and other reports

Filtering back-flow and noisy pulsers from the transactions

Fleetwatch FMS · RIH Unit Setup
Filter Illegal Fluids Setting
The Filter Illegal Fluids setting keeps small, unauthorized fluid counts from being recorded in a transaction. These counts can come from back-flow, fluid movement when a hose is pulled out or retracted, or a noisy pulse meter.
0.1
Recommended starting value (minimum)
As low as possible
So real problems aren’t hidden

Where to Find the Setting

In Data Tools, open the RIH unit and go to:

Edit RIH Unit  ›  RIH Options tab  ›  Filter Illegal Fluids

Each RIH has its own value, so set it on every fuel lane and maintenance bay RIH, then save.

Edit RIH Unit, RIH Options tab, with Filter Illegal Fluids set to 0.1
Example: Filter Illegal Fluids set to 0.1 on the RIH Options tab.

How It Works

During a transaction, the RIH counts pulses from every fluid’s pulse meter, including fluids the vehicle isn’t authorized for. If an unauthorized fluid’s count is at or below the filter value, the system treats it as noise. The transaction shows that quantity as *0.00, which means an illegal fluid was detected but the amount was within the filter.

Example: filter set to 0.2

A diesel bus is being fueled, and the CNG pulser sends a false count during the transaction.

False CNG count Result Shown in the transaction
0.2 equivalent gallons Filtered Highlighted as *0.00. Not counted toward fluid totals.
More than 0.2 equivalent gallons Not filtered Recorded as an unauthorized fluid flow that should be investigated.

The filter applies only to fluids the vehicle isn’t authorized for. Authorized fluids are recorded normally. The value uses the same units as the fluid totals: gallons, or equivalent gallons for CNG.

Common Causes of Small False Counts

Back-flow Fluid moving backward through the meter when pressure drops, often because a check valve is worn or missing.
Hose extension or retraction Pulling a hose off a reel or letting it retract can shift fluid in the line enough to turn the meter a little.
Pressure and temperature changes The pump starting up, or fluid in a closed line expanding as it warms, can move a small volume through the meter.
Noisy pulse meter or signal line Electrical noise on the pulser wiring can look like real pulses. Typical causes are unshielded or poorly grounded cable, cable run alongside motor or power wiring, and loose connections.
⚠ Keep the value as low as possible
A filter set too high can hide real problems: fluid dispensed to the wrong vehicle, a leaking valve, or uncontrolled fuel or fluids. Start at 0.1. Raise it only in small steps, and only if false counts continue after the hardware has been checked.
Tips
• Fix the cause, not just the symptom. If one lane keeps logging false counts, check its check valves, hose reels, and pulser wiring before raising the filter.
• Review transactions from time to time for frequent *0.00 entries. A sudden increase on one RIH or one fluid often points to a hardware issue.
• Unauthorized flows above the filter value always need follow-up. They may be a real dispensing error rather than noise.
Questions about the Filter Illegal Fluids setting? Reach out to Fleetwatch Support.