Steam and Water Piping

While the boiler is operating, examine all steam and water piping-including connections to the columns-for leaks. If any leaks are found, determine if they are the result of excessive strains caused by expansion and contraction or other causes. Listen for water hammer; if found, determine the cause. Look for undue vibration, particularly in piping connections to the boiler. Where excessive vibration of piping is found, examine connections and parts for crystallization.

Water Columns and Gauge Glasses

With steam on the boiler, blow down the water columns and gauge glasses and observe the action of the water in the glass to determine if the connection to the boiler or the blowoff piping is restricted or not properly free. This will help you determine the true condition of high- and lowwater alarms and of the automatic combustion equipment.

Devices

While the boiler is operating, cause the individual mechanisms of LOW-WATER FUEL CUTOFF and/or WATER-FEEDING DEVICES to operate to assure they function properly.

Where a float-operated, low-water cutoff or water-feeding device or a combination low-water fuel cutoff and water-feeding device is provided, its operation should be tested by opening the drain to the float bowl and draining the bowl to the lowwater level of the boiler. When the low-water point is reached, the mechanism of the low-water fuel cutoff should function and shut off the fuel supply to the boiler until boiler water is added to the proper level. Also, at the low-water point, the mechanism controlling the feedwater supply should function to start the feedwater.

Where there is a low-water fuel cutoff device controlled by excess temperature generated in a temperature element located inside the boiler, its operation may be tested by blowing off the boiler to its allowable low-water level. On or before the low-water level is reached, the device should function to shut off the boiler fuel supply until boiler water is added to the proper level.

On high-temperature water boilers, the flow through the boiler should be restricted to the minimum allowed, as shown by the manufacturer's operating data. The point at which fuel cutoff takes place should be noted and adjustments made as required.

With steam on the boiler, observe the STEAM GAUGE pointer for sticking or restriction of its movement. Blow down the pipe leading to the gauge to assure that it is free. Attach an approved test gauge to the pipe nipple provided for this purpose, and compare the accuracy of each steam gauge on the boiler with that of the test gauge. When inaccuracy of any gauge is evidenced or suspected, it should be removed and calibrated by means of a deadweight gauge tester or other device designed for this purpose. When several boilers are in service and connected to a common steam main, compare the readings of the separate gauges. All TEMPERATURE-INDICATING DEVICES should be observed for indications of excessive temperature, particularly during and immediately after the time high-load demands are made on the boiler. While the boiler is operating under normal conditions, observe the operation of all METERING AND RECORDING DE-VICES. When there is evidence that any such device is not functioning properly, it should be adjusted, repaired, or replaced as necessary.

Blowoff Valves

Test the freedom of each blowoff valve and its connections by opening the valve and blowing off the boiler for a few seconds. Determine if the valve is excessively worn or otherwise defective, and if there is evidence of restrictions in the valve or connected piping preventing proper blowoff of the boiler.

Stop and Check Valves

While the boiler is operating, inspect the operating condition of each stop and check valve where possible. Serious defects of externally controlled stop valves may be detected by operating the valve when it is under pressure. Similarly, defects in check valves maybe detected by listening to the operation of the valve or observing any excessive vibration of the valve as it operates under pressure.

Pressure-Reducing Valves

While there is pressure on the system, open and then close the bypass valve as safety and operating conditions permit. Also, observe the fluctuation of the pressure gauge pointer as an aid in determining possible defects in the operation of the pressure-reducing valve or the pressure gauge. Look for any evidence that may indicate improper condition of the relief or safety valves provided for the pressure-reducing valves.

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