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CONTROLS AND ACCESSORIES
SAFETY VALVE
The safety valve should open automatically if the boiler
steam pressure exceeds the pressure rating of the valve
(15 psig). Should it ever fail to open under this condition,
shut down your boiler. If valve discharge occurs, or valve
fails to open as described above, contact an authorized
contractor or qualifi ed service technician to replace the pop
safety valve and inspect the heating system to determine
the cause, as this may indicate an equipment malfunction.
STEAM PRESSURE GAUGE
Every system should have a pressure gauge installed in the
boiler. This gauge enables you to monitor the pressure in
the system. If the safety devices fail to shut off your boiler
at the proper settings, notify your serviceman immediately.
WATER LEVEL GAUGE
The water level in the boiler can be seen through the glass
tube in the water level gauge at side of boiler. Correct
cold boiler water level is stamped on side jacket panel.
The water level should be checked regularly for the proper
level.
On the right side jacket panel of the boiler, there are
three holes for the glass water level gauge. The top hole
is common for both types of low water cut off, and is used
for the upper gauge glass fi tting. The middle hole, 9” down
from the top hole, is used for the bottom gauge glass fi tting
for the Model 67D-1 and 47-2 fl oat type low water cut off.
The lowest hole, 12
1
/4” down from the top hole, is used for
the bottom gauge glass fi tting for the Model PS-802 probe
type low water cut off. The hole that is not being used is
covered with a sheet metal knockout.
STEAM PRESSURE CONTROL
The steam pressure limit control (pressuretrol) shuts off
the gas to the main burners when the steam pressure in
the boiler reaches the cut-off setpoint (i.e. the sum of the
cut-in and the differential setpoints). Burners refi re when
the steam pressure drops to the cut-in setpoint. System
pressure requirements are based on the size and condition
of the pipes, and the load.
LOW WATER CUT-OFF
1. Model 67D-1
This is a fl oat operated switch which shuts down the gas
burner if water falls below the visible bottom of the gauge
glass.
2. Model PS-802
This is an electronic probe type LWCO. The probe is located
inside the boiler. The LWCO will shut down the burners if
the water loses contact with the probe for a period of 10
seconds.
Refer to manufacturer’s instructions (enclosed) for more
information.
WATER FEEDER (Optional)
The Model WF-2U-24 water feeder maybe used with either
of the available low water cutoffs. The water feeder’s job is
to maintain a safe minimum water level. It’s used to keep
the boiler running by compensating for minor evaporative
steam leaks, and to prevent freeze-ups if the homeowners
are away and a return line should spring a leak.
McDonnell and Miller Model 101 water feeders may be
used, however the water feed rates are too high and need
to be regulated or throttled and wiring will have to be
revised. Consult the boiler manufacturer before using these
or any other non-standard types of controls.
The automatic water feeder is a safety device, not a
convenience item. It is not designed to maintain a “normal”
water line. The water feeder does not take the place of a
responsible person monitoring and maintaining the normal
water line. Steam boilers require personal attention.
VENT DAMPER
This is an automatic, motorized stack damper that has
been developed to increase the effi ciency of heating
systems by reducing standby losses from the boiler and the
conditioned air space. The damper closes the chimney vent
when the burner is off and fully opens it when combustion
is required.
ROLLOUT SWITCH
(FLAME ROLLOUT SAFETY SHUTOFF)
The rollout switch is a temperature-sensitive fuse link
device. It is located on the boiler base just outside the
fi re box. In the event of heat exchanger fl ueway blockage
causing fl ame to roll out of the fi re box, the fuse will blow,
shutting down the fl ow of gas to the main burners. The
fuse does not change in appearance when blown.
If the rollout switch blows, it must be replaced with an
exact replacement. Check heat exchanger fl ueways for
blockage when restoring system to operating condition. Do
not operate system without a rollout switch.