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CSLD Troubleshooting
CSLD Alarms
ALARM: CSLD RATE INCR WARN
A CSLD Rate Increase Warning indicates fluid is entering the tank during the leak test. This warning indicates a
higher than acceptable positive increase in product calculated from the CSLD Rate Table. The threshold amounts
are listed below.
Single tank configuration:
PD - 95% = -0.17 gph
PD - 99% = -0.16 gph
Manifolded Tank configuration:
PD - 95% = -0.16 gph
PD - 99% = -0.15 gph
From the Home Screen, touch the DIAG button, the Tank Test button and then the CSLD Rate Table tab to view
the CLSD Rate Table results.
SOME POSSIBLE Causes of positive rate increases
1. Incorrect temperature coefficient entered during setup. Verify that the temperature coefficient of thermal
expansion is set correctly according to the TLS Setup specifications listing for various product grades.
2. Manifold Tank Siphon Bar Leakage
Rate increases can occur in siphon manifolded tanks due to a leaking siphon system. Since the siphon piping
is normally full of fuel this can become a source of rate increases. If the siphon does not hold, product will drain
back slowly into the tanks during idle periods. The fuel from the siphon piping will increase the volume in the
tank which will cause a CSLD rate increase warning. Test and repair the siphon system per the manufacturer’s
recommendations.
3. Leaks In Submersible Pumps
• Around the packer O-ring.
• At the threads of the two-inch pipe coming from the turbine motor.
• The gasket between the turbine motor and mounting flange.
• At any seal which would allow the column of fuel being held in the pump by the check valve to leak back slow-
ly into the tank.
4. Manifolded tanks are programmed incorrectly in In-Tank setup.
Tanks in a manifolded set must be programmed as a set, and you must select
CSLD
as the Leak Test Frequen-
cy for each of the tanks.
5. Defective Line Check Valves
Fluid from the line piping leaking back into the tank through a defective Line Check Valve may cause a rate in-
crease. Verify that the line piping holds pressure after pumping stops.
6. Thermal Expansion In The Lines
When the product temperature in the tank is lower than the ground temperature, product in the line will expand
after dispensing. After pumping ceases the line check valve or pump check valve will maintain pressure in the
line. As the ground warms the product in the line expands. This expansion causes a corresponding pressure in-
crease in the line therefore the pressure relief valve opens. The relief valve, relieves this increased pressure by
allowing fuel to flow back into the tank. The flow from the line back into the tank can be a source of rate in-
crease warnings. Typically thermal expansion’s impact on CSLD is short lived. However, in extreme cases ther-
mal expansion can be a source of CSLD rate increase warnings. If thermal expansion is suspected as the
source of CSLD rate increase warnings you should inspect the site layout to determine if it is susceptible to ex-
