Cell temperature reading above ~140°F. Clean the cell, check heater placement, replace the cell if the sensor is bad — never bypass it.
The cell thinks the water is over ~140°F. Clean it, check it's not right after a hot heater, and replace the cell if the sensor has failed.
HOT means the cell is reading water temperature above about 140°F (COLD is below about 50°F). Inspect and clean the cell, reset average salt, make sure the cell is not directly downstream of a running heater or chiller, and replace the cell if the reading stays wrong at normal water temperature.
Cell temperature reading above ~140°F. Clean the cell, check heater placement, replace the cell if the sensor is bad — never bypass it.
If the pool is not actually near 140°F, the cell sensor is likely wrong.
Verify real water temperature.
HOT is a cell temperature reading above 140°F. A normal swimming temperature with a HOT display points to sensor or placement issues, not a boiling pool.
The cell must not sit directly downstream of a running heater or chiller.
Check heater/chiller placement.
Hayward's guide calls out placement directly after a heater/chiller as a cause of bad temperature readings. Correct plumbing or run conditions before replacing parts.
Inspect and clean the cell, then reset the average salt reading as the guide describes.
Clean the cell and reset average salt.
Follow Hayward's cell inspection/cleaning steps, then reset average salt. Recheck whether HOT clears at normal water temperature.
Persistent HOT at normal water temperature means the cell temperature sensor has likely failed.
Replace the cell if the sensor failed.
Hayward's path is to replace the cell — not to bypass the thermistor. Sensor-defeat 'fixes' remove a safety reading and are not an approved repair.
As an Amazon Associate I earn from qualifying purchases. CodeFix earns a commission if you buy through these links, at no extra cost to you.
If the steps above did not clear it, this is the part most people need.
When HOT persists at normal water temperature after cleaning and placement checks, Hayward points to a failed cell temperature sensor — replace the cell with the correct TurboCell for your system.
Hayward's troubleshooting guide treats HOT as a cell reading above 140°F (COLD below 50°F).
No. That defeats a temperature input. Hayward's fix path is clean/reset, check placement, then replace the cell if the sensor failed.
If real water is not that hot, it's a bad reading. If water were truly that hot, shut the system down and investigate heating equipment — don't ignore it.
Hayward AquaRite Troubleshooting Guide AQR159d.
Source: Hayward AquaRite Troubleshooting Guide AQR159d (HOT / COLD temperature readings). Written by a Florida pool service owner. Updated 2026-10-14.