How to Maintain a Heating Boiler

You may need to bleed air from an old-fashioned radiator on occasion.

A hot water boiler system is not nearly as common as it was half a century ago when many residential homes received heat through the network of pipes running to a radiator. Maintenance of a residential boiler system mainly means periodic inspections of the safety valve, steam pressure gauge and water level gauge. It pays to be aware of how these components work when your boiler system is working at peak efficiency so you'll be aware when things are out of order.

Things You'll Need

• Replacement safety valve
• Hose
• Bucket

Instructions

1. Locate the safety valve on top of the boiler and test it at least once a month during the heating season. Standing clear of the valve pipe, make sure that steam comes out of the safety valve when you depress the handle. Replace the safety valve if no steam shows up during routine maintenance.

2. Give the steam pressure gauge a light tap to ensure that it is not stuck. The pressure of the steam in your boiler system needs to be somewhere between 2 and 10 lb. per square inch (ppsi). If the reading does not fall within that range, turn off the boiler and call for professional servicing.

3. Open the valves at each end of the sight glass in the gauge once a month for a maintenance check. The water level should read somewhere in the middle of the glass. If no water is visible, shut the boiler down to allow it to cool. Add water through the fill valve on the water inlet pipe before starting the boiler back up again. If your boiler is equipped with an automatic water fill valve and no water is visible, call for servicing.

4. Drain water from the expansion tank if the pressure gauge is reading high or the tank itself feels unusually hot to the touch. Turn off the power and water to the boiler and allow enough time for the water in the tank to cool. Attach a hose to the combination valve and open it so that water is flowing out. Allow the water to flow until the pointers on the pressure gauge coincide. Close the valve and restore power to the unit and then start it back up again.

5. Bleed air from the convectors and radiators if your boiler units are not equipped with automatic air valves. The convector and radiator will not heat efficiently if air is trapped inside. Routine maintenance should include bleeding the radiator and convector at the beginning of every heating system. Bleed air if the boiler system starts providing uneven heat throughout the house.

Tips & Warnings

• You may need a screwdriver, wrench or special key to open the valve on the convector for bleeding; it all depends on the particular model

• The steam produced by a boiler system can scald bare skin so always perform maintenance with gloves on for protection against accidents.

References

• "Time-Life Fix-It-Yourself: Home Heating and Cooling;" Kenneth Winchester, Ed.; 1991
• "Complete Home Improvement and Repair;" Don Vandervort, Ed.; 2000
• HPAC Engineering: Maintaining a Boiler