HOT SPRING SPAS LIMELIGHT SERIES Flashing Red Logo

High-Limit Thermistor

The high-limit thermistor is a Negative Temperature Coefficient (NTC) resistor that monitors the heater manifold; over time, the internal potting can degrade, causing the resistance to drift and signaling a false overheat condition to the control board. This triggers a safety lockout (flashing red) to prevent dry-firing of the heater element. Replacing the sensor restores the correct resistance-to-temperature logic.

SilentFlo E5 Circulation Pump

If the circulation pump's internal impeller is jammed or the motor windings have failed, water becomes stagnant inside the heater manifold. The lack of convective heat transfer causes the water in the immediate vicinity of the element to reach the high-limit threshold almost instantly, tripping the thermal safety switch.

SKU: 74427

Tri-X Ceramic Filter

Accumulated debris or calcification on the filter media increases hydraulic resistance, reducing the flow rate below the minimum required to keep the heater manifold cool. This low-flow condition results in localized thermal spikes that trigger the high-limit protection mode.

SKU: 73178