Cleaver-Brooks CBH 40 - Normal OPERATION-All Fuels

Chapter 4-Starting and Operating Instructions
material may be present in either new or
renovated gas lines unless adequate care is taken
in cleaning, purging and providing a suitable
strainer.
When flame is established leave the burner in low
fire
position for approximately 30 minutes or until
boiler is properly warmed, unless it reaches its nor-
mal operating pressure or temperature sooner.
A hot water boiler must have a continuous flow of
system water through the vessel during the warm-
up period. If conditions permit, the entire water
content of the system and boiler must be warmed
prior to increasing fuel input.
After normal pressure or temperature is approach-
ed at low fire, turn the damper positioning switch
to "high''. Observe the burner as it progresses to
"high'' fire position. In the event the butterfly gas
valve movement is not properly coordinated with
the air damper, it is possible that increased sec-
ondary air may extinguish the low fire flame. After
the unit is thoroughly warmed and running in high
fire, a combustion analysis should be made, with
instruments, and fuel flow and/or air flow regu-
lated as required. Refer to the adjustment pro-
cedures in Chapter 5. To properly perform this
analysis and adjustment it is necessary that burner
be allowed to fire at maximum rate and suffici-
ently long enough to achieve desired results.
The main gas pressure regulator and the pilot gas
regulator have a vent opening which must be free
from obstructions for proper operation of the de-
vice. Local codes or insurance requirements may
require discharge piping to the outside of the build-
ing. Make sure that this piping is not obstructed.
Refer to Section E of this chapter for normal start-
ing operating and shutdown information.
E. NORMAl OPERATION-All fUElS
START-UP
Check water level and supply.
Check setting of all operating controls. Check all
reset and lockout mechanisms.
Programmer timer dial should be at the black dot.
4-4
On a combination fuel unit (Series 200) the fuel
selector switch should be set for the appropriate
fuel.
Turn the burner switch "on". Observe action of
burner and controls to assure proper functioning.
Allow boiler to run at low fire until properly
warmed up before allowing burner to go to high
fire.
OPERATING
Normal operation should be with the damper posi-
tioning switch set at "auto" and under the control
of the high-low fire control.
With the switch set at "auto", burner will operate
on a high-low firing basis according to the load de-
mands.
The burner will continue to operate until the oper-
ating limit pressure or temperature setting is
reached, unless:
a. Burner is manually turned "off'.
b. Low water condition is detected by low water
level control.
c. Current or fuel supply is interrupted.
d. Pressure of combustion air drops below mini-
mum level.
NOTE: There can be other reasons for shutdowns
such as motor overload, flame outages,
tripped circuit breakers, blown fusetrons
or through interlock devices in the system.
SHUTDOWN
When the operating· limit pressure or temperature
control opens due to pressure or water temperature
increase, or if the burner switch is turned "off', the
following sequence occurs:
The fuel valve is de-energized and flame extin-
guished. The timer resumes operation and the
blower motor continues running to force air
through the furnace during the post purge period.
At the end of the post purge the blower motor is
de-energized. The timer has returned to its original
position and stops.
Refer to Chapter 3 for timing sequence.
Unit is ready to re-start.