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NORA Oilheat Technicians Manual

2. If a relief valve is leaking: Steam system—check the steam gauge and the pressuretrol. Remember that residential steam systems should operate at a maximum of 2 PSI and steam relief valves open at 15 PSI. If the relief valve opens, it is likely either the valve or the pressuretrol is malfunctioning. Hot water system—a number of things can cause the relief valve to open on a hot water system: • A full expansion tank. • A bad diaphragm on a pressurized expansion tank. • A malfunctioning or improperly set aquastat. • A misadjusted or malfunctioning pressure-reducing valve. • A leaking domestic hot water coil. • A malfunctioning relief valve. Water heater—check the aquastat and the domestic hot water pressure. Helpful hint—many municipalities require the installation of backflow prevention devices that can cause heating system relief valves to open. Often the only way to stop the valve from opening is to install a domestic water expansion tank. 3. Circulator flange gaskets can leak. Tightening the flange may stop the leak but it is usually better to replace the gaskets once they start leaking. 4. Older style circulators often had a separate bearing assembly that would leak water from a weep hole when they became defective. With this type of leak, you can either change the bearing assembly or replace the entire circulator with a modern water lubricated model. 5. If the boiler itself is leaking, it is usually beyond repair. Turn off the electric power and the water supply to the unit, drain the remaining water from the system and contact your supervisor for instructions. Helpful hint—Customers often complain of water leaks during rainstorms. These “water leaks” are sometimes caused by rainwater coming down the chimney and leaking onto the floor. Remember that each gallon of oil burned creates a gallon of water in the combustion gases. If the boiler water temperature drops below 130 degrees, the water in the combustion gases will condense in the heat exchanger, mimicking a water leak. #7 Oil leaks Oil leaks are a serious concern because they can lead to significant damage. Your approach to these calls will depend on the severity of the leak. Minor leaks typically occur at: 1. Brass fittings: If the system has compression fittings, they should be replaced with flare fittings. If a flare fitting is leaking, turn off the oil supply then Chapter 15—Service Procedures 15-11 Remember that each gallon of oil burned creates a gallon of water in the combustion gases. If the boiler water temperature drops below 130 degrees, the water in the combustion gases will condense in the heat exchanger, mimicking a water leak. Chapter 15 Service Procedures


NORA Oilheat Technicians Manual
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