750-96 (revised 2010)
Model CB Packaged Boiler Manual
1-7
1.6 — Steam Controls: All Fuels
1.6 — Steam Controls: All Fuels
Control Description
1. Steam Pressure
Gauge
Indicates boiler’s internal pressure.
2. Operating Limit Pres-
sure Control
Breaks a circuit to stop burner operation on a rise of boiler pressure above a selected set-
ting. It is adjusted to stop or start the burner at a preselected pressure setting.
3. High Limit Pressure
Control
Breaks a circuit to stop burner operation on a rise of pressure above a selected setting. It
is adjusted to stop the burner at a preselected pressure above the operating limit control
setting. This control is normally equipped with a manual reset.
4. Modulating Pressure
Control
Senses changing boiler pressures and transmits this information to the modulating motor
to change the burner’s firing rate when the manual-automatic switch is set to automatic.
5. Low Water Cutoff and
Pump Control
This float-operated control responds to the water level in the boiler. It performs two dis-
tinct functions:
a) Stops firing of the burner if water level lowers below the safe operating point and ener-
gizes 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. This type requires manual resetting to start the burner after a low water
shutdown.
b) Starts and stops the feedwater pump (if used) to maintain water at the proper operat-
ing level.
NOTE: Determine that control is plumb after shipment and installation and throughout
operating life.
6. Auxiliary Low Water
Cutoff (optional equip-
ment)
This control breaks the circuit to stop burner operation in the event boiler water drops
below the master low water cutoff point. Manual reset type (optional equipment) requires
manual resetting in order to start the burner after a low water condition.
NOTE: Determine that control is plumb after shipment and installation and throughout
operating life.
7. Low Water Pump
Control Instruction Plate
Gives instructions and information for operation of low water devices.
8. Water Column This assembly houses the low water cutoff and pump control and includes the water
gauge glass, gauge glass shutoff cocks, and trycocks.
9. Water Column Drain
Valve
The water column drain valve is provided so that the water column and its piping can be
flushed regularly to assist in keeping cross-connecting piping and float bowl clean and
free of sediment. A similar drain valve is furnished with auxiliary low water cutoff
(optional equipment) for the same purpose.
10. Water gauge Glass
Drain Valve
This valve is provided to flush the gauge glass.
11. Test Valve This valve allows the boiler to be vented during filling, and facilitates routine boiler
inspection.
12. Safety Valve Safety valves relieve the boiler of pressure higher than the design pressure, if designated.
Safety valves and their escape piping are to be installed to conform to the ASME Code
requirements.
NOTE: Only the safety valves manufacturer’s representative should adjust or repair the
boiler safety valves.
To Next Page
Loading...
