Bradford White Water Heater Error Code 2 — Temperature Sensor Fault Fix

Bradford White water heaters with the Icon System control flash error codes through the status LED. Error code 2 (two slow flashes) means a temperature sensor fault — the gas control valve’s built-in temperature sensor (thermistor) has failed or gone out of acceptable resistance range.

The heater shuts down as a safety measure. Without a valid temperature reading, the control can’t regulate burner operation. The fix is usually a gas control valve replacement, but you may be able to confirm the diagnosis yourself first.

Jump to Fix

• What Error Code 2 Means
• Quick Reference Table
• Most Common Causes
• Step-by-Step Diagnosis
• How to Test the Temperature Sensor
• Parts and Costs
• When to Call a Tech

What Error Code 2 Means

The Icon System control uses a thermistor inside the gas control valve to measure water temperature at the tank bottom. When the control detects a thermistor reading that’s outside the valid range — typically an open circuit (infinite resistance) or a short circuit (near-zero resistance) — it triggers error code 2.

Models affected: Bradford White gas water heaters with the Icon System gas valve — Defender Safety System, DSI, and FVIR-compliant models manufactured from roughly 2005 to present.

The heater will not operate while this code is active. You’ll have no hot water until the sensor circuit is restored or the control valve is replaced.

Quick Reference Table

Most Common Causes

The gas control valve on Bradford White water heaters is a sealed assembly. The temperature sensor is embedded inside — you can’t replace it separately. This means error code 2 almost always requires a new gas control valve.

Step-by-Step Diagnosis

Step 1: Check the error code

Turn the gas control knob to OFF and back to your temperature setting. Watch the LED on the gas valve.

• 2 slow flashes: Confirms temperature sensor fault. Proceed to Step 2.
• Different flash count: You may have a different issue. Check the full Bradford White error codes guide.

If the code clears after a power cycle but returns later, the thermistor is intermittently failing — it will need replacement soon.

Step 2: Inspect the wiring connector

The gas control valve has a wiring harness that connects to the temperature sensor inside the valve body. On most Bradford White models:

1. Turn the gas control knob to OFF and wait 5 minutes
2. Locate the wire harness connector on top of the gas valve
3. Gently disconnect and re-seat it a few times to clean the contacts
4. Check for bent, corroded, or pushed-back pins
5. Apply dielectric grease to prevent future corrosion

If the pins are clean and the connector is fully seated, proceed to Step 3.

Step 3: Measure thermistor resistance

You’ll need a digital multimeter for this test. The temperature sensor (thermistor) should show a specific resistance based on the water temperature at the tank bottom.

1. Set your multimeter to Ohms (Ω)
2. Disconnect the wire harness from the gas valve
3. Measure across the two pins that go into the valve body (the ones going to the thermistor, not the incoming harness)
4. Compare to these typical values:
   • Cold water (50-60°F): 12,000–20,000 Ω
   • Room temp (70-80°F): 8,000–12,000 Ω
   • Warm water (100-120°F): 3,000–6,000 Ω

OL (open loop) on the multimeter means the thermistor has failed open — the gas valve must be replaced.

Near-zero resistance means the thermistor has shorted — the gas valve must be replaced.

Step 4: Check for water damage

Water intrusion into the gas valve connector is a common cause of error code 2, especially on heaters installed in humid basements or crawl spaces.

1. Unplug the wire harness
2. Look for white or green corrosion on the metal pins
3. Look for moisture inside the connector housing
4. If present, clean with electronic contact cleaner and apply dielectric grease

If the pins are corroded beyond cleaning, you may need the gas valve wire harness as well.

How to Test the Temperature Sensor

To be thorough, you can back-probe the incoming harness at the control board end to check continuity all the way through. This is more advanced — skip it if you’re not comfortable working with a multimeter near live gas valve circuitry.

1. With the harness disconnected from the gas valve, check for continuity between each pin and ground
2. There should be NO continuity to ground — if there is, the sensor wire is shorted to the tank or jacket
3. Check for broken wires by gently flexing the harness along its length while watching the resistance reading

Parts and Costs

Need help finding your model number? Check the data plate on the front of the water heater near the gas valve. It lists the model and serial number you’ll need to cross-reference parts.

When to Call a Tech

Call a licensed plumber or water heater technician if:

• Your multimeter test confirmed an open or shorted thermistor (gas valve needs replacement)
• You’re not comfortable working with gas appliances
• The error code returns after connector cleaning and re-seating
• The water heater is over 10 years old — replacing the whole unit may be more cost-effective than repairing the gas valve

Gas valve replacement cost with a technician: $300–$600 installed, including parts and labor. Compare to a new water heater installed at $900–$1,500.

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• Bradford White Water Heater Error Codes Complete Guide

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