Triangle Tube water heater runs but hot water output is lukewarm or cooler than setpoint.

Safety: Avoid raising setpoint above safe levels to compensate for faults.

• 1. Confirm DHW setpoint: Check the control panel and ensure the DHW setpoint is high enough (e.g., 120°F / 49°C). Adjust if necessary.
• 2. Check gas supply: If other gas appliances are weak or not working, there may be a gas supply issue. Contact your gas provider.
• 3. Inspect mixing valve: If a thermostatic mixing valve is installed, verify that its setting has not been turned down. Adjust according to manufacturer instructions.
• 4. Heat exchanger scale: Long-term operation in hard water areas can scale the DHW heat exchanger. Have a technician descale the plate or tank coil using approved chemicals.
• 5. Sensor verification: Compare the displayed DHW temperature to an accurate thermometer at a nearby tap. If the display is much higher than actual, the DHW sensor may be misreading and should be replaced.