Hey, take a deep breath. Your hot tub displaying an ERR error message where the temperature should be is frustrating, but it’s usually fixable. This error typically means your spa’s control system can’t get a proper temperature reading from the sensor, which triggers a safety shutdown to protect your equipment.
Step-by-Step Fixes
Step 1: Power Cycle Your Hot Tub (2 minutes)
Turn off your hot tub at the breaker panel, not just the topside control. Wait 30 seconds, then flip it back on. This simple reset clears temporary glitches in about 40% of cases. When the system boots up, watch for the temperature display to return to normal digits instead of ERR.
Step 2: Check Your Water Level (5 minutes)
Low water can expose temperature sensors to air, causing erratic readings. Look for the water line – it should be halfway up the skimmer opening or about 1-2 inches above the highest jet. If it’s low, grab your garden hose and top it off. Wait 5 minutes after filling for the system to stabilize before checking if the error cleared.
Step 3: Inspect and Clean Your Filter (15 minutes)
A clogged filter restricts water flow past the temperature sensor. Pull out your filter cartridge and check for debris, oils, or that gray-green biofilm that builds up. If it looks dirty, rinse it thoroughly with a garden hose, spraying between each pleat. For stubborn buildup, soak it in filter cleaner for an hour. Reinstall and restart your spa.
Step 4: Test the Temperature Sensor Connection (20 minutes)
Turn off power at the breaker first. Remove your spa’s access panel (usually on the side where your equipment is). Look for a small sensor with two wires – it’s often clipped to the heater tube or inserted into a well. Check that the connector is firmly seated and free of corrosion. Green or white buildup means moisture damage. Clean connections with electrical contact cleaner if needed.
Step 5: Bypass Test Your Sensor (30 minutes)
This diagnostic step helps determine if your sensor is truly failed. With power off, disconnect the temperature sensor wires from the control board. Using a multimeter set to resistance (ohms), measure across the sensor terminals. At 77°F, you should see around 10,000 ohms. Significantly different readings indicate sensor failure. Most sensors cost $30-60 and are ideal for DIY replacement if you’re comfortable with basic wiring.
Likely Causes
Cause #1: Failed Temperature Sensor
Temperature sensors have a lifespan of 5-7 years in most hot tubs. They’re constantly exposed to hot water and chemicals, which gradually degrades their accuracy. You’ll know it’s the sensor if your ERR message appears consistently, even after resets. The fix involves replacing the sensor – a part that costs under $50 and takes about 30 minutes to swap with basic tools.
Cause #2: Control Board Communication Issues
Your spa’s control board processes temperature data from the sensor. When circuit boards age or get moisture damage, they struggle to interpret sensor signals correctly. Signs include intermittent ERR messages that come and go, or errors appearing only at certain temperatures. Board issues are best diagnosed by a technician, as replacement boards run $200-500 and require matching to your specific spa model.
Cause #3: Flow Problems Affecting Sensor Readings
Temperature sensors need consistent water flow to read accurately. Blocked jets, failing circulation pumps, or air locks in the plumbing create dead spots where sensors can’t function properly. You’ll notice weak jet pressure or gurgling sounds along with your ERR message. Start by checking for closed valves, then ensure all jets are open. Persistent flow issues often trace back to pump problems requiring professional service.
When to Call Expert Help
Contact a spa technician when your ERR error persists after trying these fixes, or if you see additional error codes appearing. Professional help is essential when you smell burning electronics, hear unusual pump noises, or if your breaker keeps tripping. Most importantly, call for help if you’re uncomfortable working near water and electricity – spa repairs aren’t worth risking your safety.
Technicians have diagnostic tools that can pinpoint issues in minutes. They’ll check voltage at the sensor, test control board outputs, and identify problems you might miss. In 2025, expect service calls to run $150-250, but catching problems early prevents thousand-dollar equipment failures.
Copy-Paste Prompt for AI Help
“My hot tub shows ERR where the temperature reading should be. The model is [YOUR SPA BRAND AND MODEL]. I’ve tried [LIST WHAT YOU’VE ALREADY ATTEMPTED]. The error started [WHEN IT BEGAN – suddenly, gradually, after an event]. My spa is [AGE] years old. What specific troubleshooting steps should I try for this temperature sensor error? Include safety precautions and when to stop DIY attempts.”
Remember, ERR messages are your hot tub’s way of protecting itself from damage. While annoying, they prevent overheating and equipment failure. Most temperature reading errors resolve with basic troubleshooting, getting you back to relaxing in perfectly heated water within a day.