Lochinvar Condensing Boiler OFN1251

Measure the water hardness in grains per gallon

Is the water hardness between 5 and 12 grains per gallon?

Consult local water treatment companies for hard water areas (above 12 grains per gallon hardness)

Measure the pH level of the water

Is the pH level between 6.5 and 8.5?

Total Dissolved Solids (TDS) Check

Measure the Total Dissolved Solids (TDS) in ppm

Ensure the water meets the requirements of the manual before filling the system.

Fill to correct system pressure

Check the system thoroughly for any leaks during initial fill and boiler startup.

Repair all leaks before proceeding further.

Connect a hose to the purge valve and route it to a drainage area.

Ensure all safety precautions are followed

Do not adjust or attempt to measure gas valve outlet pressure

Avoid any actions that could result in fire, explosion, or death

Disconnect the flanged connections from the venturi and blower

Disconnect the two external wires connected to the enable terminals on the connection board.

Connect a voltmeter across the two incoming wires and close each thermostat, zone valve, and relay in the external circuit one at a time. Record the voltmeter reading across the incoming wires.

If a voltage occurs, was the external wiring checked and corrected?

Reconnect the external thermostat circuit wires to the connection board.

Vent any remaining air from the system using manual vents