Panasonic water heater shows H25; unit may not start in very cold conditions.

Freeze and burst risk: If you suspect the unit is frozen, do not force operation. Pipes or the heat exchanger may burst.

• 1. Check ambient temperature: If below the heater's minimum operating temperature, provide temporary heating to the area or wait for warmer conditions.
• 2. Inspect for visible ice: Look for frost or bulging on exposed pipes. If present, shut off water and gently warm the area.
• 3. Drain the unit (if at risk of freezing):
  • Follow Panasonic's procedure to drain water from the heater to prevent damage.
• 4. Improve insulation: Add insulation to pipes and around the unit as recommended by Panasonic.
• 5. If H25 persists in normal temperatures: The freeze sensor may be faulty and should be replaced by a technician.