November 18, 2025
Automatic Tank Gauging (ATG) alarms: how to interpret Veeder-Root, INCON and OPW
By Dagoberto Torres
Advanced Technician
The Automatic Tank Gauging system (ATG: Automatic Tank Gauging) is the nervous system of a modern station. When a probe detects water, a leak alarm fires, or the system reports an inventory discrepancy, what happens in the next 30 minutes determines whether the problem stays contained or escalates to a spill, a regulatory sanction, or both.
This article covers the three most common ATG systems at Panamanian stations — Veeder-Root TLS, INCON TS, and OPW SiteSentinel — and explains what each type of alarm means, what level of urgency it carries, and what steps to follow.
What an ATG does exactly
An ATG monitors in real time:
1. Product level in each tank (magnetostrictive probe).
2. Free water level at the bottom of the tank (separate water probe).
3. Temperature of the product (for volumetric compensation).
4. Sump sensors (liquid in dispenser sumps or tank sumps).
5. Interstitial sensors (for double-wall tanks).
6. Calculated inventory with thermal compensation.
7. Sales patterns vs inventory (SIR statistical detection if enabled).
When any threshold is crossed, the system issues an alarm: visual on the console, audible, and on modern systems also via email/SMS.
Common systems in Panama
Veeder-Root TLS-350 / TLS-450
The most common at Panamanian stations. TLS-350 is the legacy version (pre-2015 installations), TLS-450 is the modern version with touch screen and IP connectivity.
Relevant features:
INCON TS-5000 / TS-1001
An alternative to Veeder-Root, with a slightly different interface but similar functionality.
Relevant features:
OPW SiteSentinel iSite / Petrovend FSC3000
Less common in Panama but present at specific branded stations.
Relevant features:
The alarms are conceptually similar across the three systems: handling changes only in how you navigate the menus.
Alarm types and priority
🔴 Critical (immediate action, now)
#### 1. Liquid sensor in interstitial sump
Veeder-Root: «INTERSTITIAL LIQUID DETECTED» / «INT SENSOR FUEL»
INCON: «Interstitial Liquid Alarm» / «Intersticial Fluido»
OPW: «Interstitial Sensor Active»
What it means: a double-wall tank has liquid in the space between walls. This indicates an inner-wall leak (product leaving the tank) or an outer-wall leak (water entering). Either way, the tank is compromised.
Immediate action:
1. Suspend sales from the affected tank.
2. Notify maintenance + the station owner.
3. Physically inspect the interstitial sump visually (the alarm may be false due to a defective sensor).
4. Start a focused tightness test.
5. If the leak is confirmed, consider reporting to MIAMBIENTE.
#### 2. Liquid sensor in dispenser sump
Veeder-Root: «DISP SUMP LIQUID» / «FUEL ALARM SUMP»
INCON: «Dispenser Sump Liquid»
OPW: «Dispenser Containment Sensor»
What it means: there is liquid in the sump under the dispenser. It can be:
Immediate action:
1. Suspend dispensing from the affected dispenser.
2. Physical inspection of the sump (see sump protocol).
3. If it is fuel: identify the source (flexible connector, seal, fitting).
4. If it is water: drain, investigate the ingress, repair.
#### 3. Leak detection via SLD / CSLD
Veeder-Root: «LEAK ALARM» / «CSLD ALARM»
INCON: «Leak Detection Alarm»
OPW: «Leak Test Failed»
What it means: the statistical leak detection system (SLD: Statistical Leak Detection, or CSLD: Continuous SLD) calculated that the tank is losing fuel beyond the threshold. This is algorithmic analysis that correlates sales vs level.
Immediate action:
1. DO NOT RESET the alarm without investigation.
2. Suspend dispensing from the tank.
3. Focused MESA 2D tightness test.
4. If confirmed, remediation plan.
🟠 Important (action within 24h)
#### 4. High water in tank (High Water)
Veeder-Root: «HIGH WATER» / «WATER FLOAT»
INCON: «High Water Alarm»
OPW: «Water Level Alarm»
What it means: the water probe at the bottom of the tank detects free water above the configured threshold (typically 1 inch).
Why it matters:
Action:
1. Verify the reading with a dipstick + detector paste.
2. Identify the cause (recent rain, recent delivery).
3. Inspect the spill bucket.
4. If confirmed, schedule water removal.
5. If E10: layered sampling to rule out phase separation.
#### 5. Inventory out of tolerance (Inventory Reconciliation)
Veeder-Root: «INVENTORY DISCREPANCY»
INCON: «Reconciliation Out of Tolerance»
OPW: «Inventory Variance Alarm»
What it means: the difference between what was dispensed (per POS) and the tank level change exceeds tolerance. Possible causes:
Action:
1. Review the detailed report for the last 7 days.
2. If a sudden spike, focus on the event.
3. If a gradual trend, evaluate dispenser calibration.
4. Check the probes, recalibrate if necessary.
#### 6. Critical low level (Low Product)
Veeder-Root: «LOW PRODUCT» / «OVERFLOW (on receiving)»
INCON: «Low Level Alarm»
OPW: «Low Product Alarm»
What it means: the tank is close to running dry, with risk of:
Action: schedule an immediate refill. If the station has redundancy (a second tank of the same product), temporarily reassign dispensing.
🟡 Attention (action within the week)
#### 7. Probe out of service (Probe Failure)
What it means: the probe stopped communicating or the readings are not consistent.
Causes: damaged cable, corroded probe, water in the head, depleted backup battery.
Action: the tank is left without electronic monitoring: operate with manual reading (dipstick) until repair. DO NOT operate blind for more than 48 hours.
#### 8. Water sensor out of service
What it means: the water probe does not respond.
Action: combine manual reading with a dipstick + detector paste until repair.
#### 9. Tank configuration modified
What it means: someone changed parameters (capacity, dimensions, alarm threshold), it may be intentional (post-recalibration) or unauthorized.
Action: check the log of who, when and why.
⚪ Informational (record, not urgent)
The fatal mistake: resetting without investigating
A dangerously common practice: the operator receives an annoying alarm, does not understand what it means, and resets it («acknowledge» or «clear») so it stops sounding.
If the alarm was a false positive (defective sensor, bad configuration), the reset is harmless.
If the alarm was real, the reset:
1. Erases the event from the active log (it may stay in history but is not visible to the next shift).
2. Reassures the operator who thinks «it's over».
3. Does not stop the underlying problem: the leak continues, the water keeps accumulating, the inventory keeps drifting.
4. Creates legal liability: if there is a spill later, the logs show that the alarm was reset without documented action, a regulatory aggravating factor.
Rule: an alarm is reset only after:
Maintenance of the ATG itself
The ATG is electronic equipment that needs its own maintenance:
| Component | Frequency |
|—|—|
| General functional check | Monthly |
| Probe calibration | Annual (see calibration) |
| Console backup battery | Every 3-5 years |
| Cables/connectors between console and probes | Annual inspection |
| Software/firmware updates | Per manufacturer (TLS-450 has regular updates) |
| Alarm configuration | Annual review |
An ATG ignored for years may have:
Integration with regulatory liability
The ATG is not optional for a modern station in Panama. SNE/MIAMBIENTE regulations require that:
1. Every operating station has a functional ATG with active probes.
2. Alarms are documented and addressed within reasonable timeframes.
3. The leak detection system is verifiable during inspection.
A station operating with an ATG disconnected, disabled, or with failed probes is in a precarious regulatory position: any spill is considered documentable negligence.
Frequently asked questions
Can I silence the alarms but keep them in the log?
Yes, «silence» is different from «acknowledge/reset». Silencing only turns off the sound. Acknowledge closes the event. But both require subsequent investigation.
Who can modify the ATG configuration?
Operationally, only trained personnel with an access code. Configuration changes (thresholds, tank geometry) require a manufacturer-certified technician and must be documented.
Is the Veeder-Root TLS-350 still supported?
Yes, but without new features. For stations operating a TLS-350, the typical upgrade cycle is to a TLS-450 with IP connectivity and email alerts, especially useful if the station operates without 24/7 staff.
Can alarms be received via WhatsApp or email?
Yes on modern systems (TLS-450, INCON with a communications module, OPW with SiteSentinel iSite). It is a useful additional layer for operators who are not on site 24/7.
What happens if I lose the ATG administrator code?
Veeder-Root and OPW have recovery processes with authorized technical support. INCON may require a factory reset. In both cases, plan ahead and document credentials in a safe place.
Conclusion
Knowing how to read an ATG alarm is not an advanced skill, it is basic operation. The real risk is not the equipment that fails: it is the equipment that fails and no one diagnoses it because the alarm is reset to make it stop sounding. No alarm is reset without investigation + record. With that rule in place, the ATG does what it was installed to do.
If your station has an ATG with frequent alarms that no one knows how to interpret, or if you suspect the probes may be miscalibrated, contact Master Services for an assessment of the current system + a documented response protocol.
—
Brands, models and procedures mentioned in this article are references based on systems common in Panama. The exact configuration and alarm handling depend on the specific model installed and its firmware.