Preparations for Startup
3-6
750-392
CBEX-DE
3.4 — Low Water Cutoff Devices: Steam and Hot Water
No adjustment is required since LWCO controls are preset. However, if the water level is not maintained, inspect
the devices immediately and replace as required.
Steam boilers: Verify the Level Master sensitivity setting is correct for your boiler.
3.5 — Combustion Air Proving Switch
Air pressure against the diaphragm actuates the
switch which, when made, completes a circuit to
prove the presence of combustion air. Since the
pressure of the combustion air is at its minimum
value when the damper is full open, the switch
should be adjusted under that situation. It should
be set slightly below the minimum pressure, but
not too close to that point to cause nuisance shut-
downs.
3.6 — Atomizing Air Proving Switch
The air pressure against the diaphragm actuates the switch which, when closed, completes a circuit to prove the
presence of atomizing air. Since the pressure of the atomizing air is at its minimum value when there is no fuel
present at the nozzle, adjustment of the switch should be done while the unit is running but not firing. The con-
trol should be set slightly below the minimum pressure, but not too close to that point to cause nuisance shut-
downs.
The control adjustment may be made during the pre-purge period of operation by stopping the programmer
during the pre-purge period through the use of the Run/Test switch.
TABLE 3-1. Level Master sensitivity settings
Boiler HP Vessel size
Level Master sensitivity
15# Steam 150# Steam
250-350 67” 2 1
400 78” 2 1
500-800 83” 2 1
NOTE: Some of the pre-start checks and adjustments described in this section involve manually interrupting the
burner sequence. For more information consult the appropriate Flame Safeguard manual for your control system.
FIGURE 3-2. CAPS switch
CAPS
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