How to Troubleshoot a Weil-McLain Furnace

Reduce the operating temperature of the boiler to no higher than 170 degrees Fahrenheit if the furnace is delivering excessive water temperatures. Excess water temperature is typically caused by stacking, which is when the water level is high enough to trigger the heating mechanism, but not low enough to deplete the current hot water level. Reducing the operating temperature aids in preventing excess water temperature due to stacking. Consider raising the thermostat-sensing bulb within the furnace to reduce the call for heat frequency.

Review the connection hoses from the Weil-McLain furnace to your water heater if you notice water on the floor. Look for corrosion along the seams of the hose. Secure the seal by applying a sealant around the hose threads. If water is not coming from the aforementioned hoses, check the seal around air vents for water leaks. If a water leak is detected coming from the air vent, contact a professional repairman.

Check the display screen on your Weil-McLain furnace if your model is outfitted with one. Review the display to narrow down your troubleshooting. If the display screen is blank and the furnace is not operating at full power, the furnace is not receiving the required 120V of electricity. Check all fuses, breakers and other power connections. Make sure all plugs, including the U-control plug at the rear in the furnace circuit board, are securely connected.