Lochinvar Boiler WHB399N

Ensure the boiler is not frozen

Shut off power and gas to the appliance if frozen

Contact the factory for further instructions if frozen

Turn off power to the boiler before any service operation

Inspect the boiler annually by a qualified service technician

Perform maintenance as designated in Table 12A

Check the expansion tank type (open, closed, diaphragm, or bladder)

Inspect the relief valve and lift the lever to verify flow

Is the relief valve discharge piped to a safe area?

Check for any signs of corrosion or tampering on the relief valve and discharge line

If the relief valve weeps or will not seat properly, replace the relief valve

Ensure the reason for relief valve weeping is not due to expansion tank waterlogging or undersizing

Was the boiler power turned off before starting the inspection?

Read Section 6 - Hydronic Piping before proceeding further

Ensure power and gas to the boiler are shut off if freezing is suspected

Confirm the boiler is not frozen before proceeding

Turn off power to the boiler before starting service operations

Inspect the entire flue gas venting system and air piping for blockage, deterioration, or leakage

Repair any joints that show signs of leakage

Verify that air inlet pipe is connected and properly sealed

Vent and Air Intake Verification

Turn off the main power to the boiler

Remove the combustion plug and insert the combustion analyzer probe

Turn on the main power to the boiler and activate it

Enter Service Mode by pressing the pinhole button

Are the combustion values within the specified range?

Re-install the plug in the vent connector

Did the boiler shut down and register an alarm?

Shut off power and gas to the appliance if the boiler may be frozen

Ensure the discharge line is connected to the relief valve

Turn off power to the boiler before any service operation

Inspect the relief valve and lift the lever to verify flow

Is the discharge line directing flow to a safe area?

Check for corrosive water conditions affecting the valve

Inspect the valve and discharge line for illegal alterations or tampering

Operate the valve lever to ensure waterways are clear