CleaverBrooks CBEX Elite Operation And Maintenance page 11

1.4 — Steam Controls (all fuels)
Low Water Cutoff and Pump Control: Float-operated control responds to the water level in the boiler. It per-
1.
forms two distinct functions:
•Stops firing of the burner if water level lowers below the safe operating point. Energizes the low-water light in
the control panel; also causes low-water alarm bell (optional equipment) to ring. Code requirements of some
models require a manual reset type of low water cutoff.
•Starts and stops the feedwater pump (if used) to maintain water at the proper operating level.
Water Gauge Glass Drain Valve: Provided to flush the gauge glass.
2.
Vent Valve: Allows the boiler to be vented during filling and facilitates routine boiler inspection as required by
3.
ASME Code.
Water Column Drain Valve: Provided so that the LWCO and its piping can be flushed regularly to assist in
4.
maintaining cross-connecting piping and in keeping the float bowl clean and free of sediment. A similar drain
valve is furnished with auxiliary low water cutoff for the same purpose.
1.4.3 — Safety Valve(s)
Safety Valves: Prevent buildup over the design pressure of the pressure vessel. The size, rating, and number of
valves on a boiler is determined by the ASME Boiler Code. The safety valves and the discharge piping are to be
installed to conform to the ASME Code requirements. The installation of a valve is of primary importance to its
service life. A valve must be mounted in a vertical position so that discharge piping and code-required drains can
be properly piped to prevent buildup of back pressure and accumulation of foreign material around the valve seat
area. Apply a moderate amount of pipe compound to male threads and avoid over-tightening, which can distort
the seats. Use only flat-jawed wrenches on the flats provided. When installing a flange connected valve, use a
new gasket and draw the mounting bolts down evenly. Do not install or remove side outlet valves by using a pipe
or wrench in the outlet.
Safety Valve Piping and Safety Valves
FIGURE 1-4.
750-368
CBEX Elite 100-1200 HP
1-5