Control Description - RBI LCD Series Installation & Operation Manual

Page 30
PROPANE GAS: Optimum results are obtained when
the boiler/water heater is operated with the manifold
pressure(s) set per Table 20. If the manifold pressure is
off by more than 5% adjust it according to steps 1
through 4 above.
Airfl ow Adjustment
1. Remove the upper front jacket panel.
2. Connect both sides of a manometer to the pressure
switch tee, Figure 17, going to one of the pressure
switches.
3. With the unit operating at high fi re the differential
pressure should match those listed in Table 15. Do
not change air pressure in lower stages.

CONTROL DESCRIPTION

Boiler Thermostat
If a thermostat is to be used to control the boiler always
follow the instructions included with the thermostat.
Proper location of the thermostat will ensure effi cient
trouble-free operation of the boiler. Mount the thermostat
to an inside wall at a height approximately fi ve feet
above the fl oor.
Avoid placing the thermostat in areas that will not
provide an accurate measurement of the room
temperature. Locating the thermostat behind a door, in
an alcove, close to a source of thermal radiation or in a
drafty area will cause poor or sporadic heating.
For a thermostat that employs an adjustable heat
anticipator, adjust the anticipator to match the current
measured in the thermostat circuit. An increased
anticipator setting may be necessary if the unit cycles
frequently. If the room temperature over-shoots the
thermostat setting, reduce the anticipator setting.
Operating Control
The preferred control setting for potable hot water is
130˚F, 54˚C. The operating control should be set to the
lowest setting that will satisfy the consumer's needs.
WARNING: Setting the thermostat or operation
control too high can result in scalding resulting
in severe personal injury!
High Limit (Aquastat)
The high limit is located in the top control area of the
boiler/water heater. A remote capillary bulb is run to a
well on the outlet side of the supply header. The high
limit can be reset by depressing the reset button on the
left jacket panel.
LCD INSTALLATION AND OPERATION INSTRUCTIONS
The water heater high limit should be set a minimum of
20˚F, 11˚C higher than the operating control. Refer to
the HOT WATER SUPPLY section for the proper supply
water temperature.
Flow Switch
A fl ow switch is provided in the water outlet piping to
prevent the boiler/water heater from firing without
adequate water fl ow through the heat exchanger.
Low Water Cutoff
If the boiler is to be installed above radiation or if
required by other codes or regulations, install a low
water cutoff in appropriate piping. Wire the switch and
any external controls in series to the "Interlock" contacts
in the control box, see the wiring diagrams included with
the unit for details. Ensure that the low water cutoff
device(s) will function properly.
Flame Sense Module
The fl ame sense module is located in the control box.
It is an intermittent pilot control device that controls the
pilot gas fl ow, spark energy to ignite the pilot gas and
the main valve(s) once pilot ignition has been proven.
Two fl ame failure alarm terminals are provided on the
fl ame sense module. For CSD-1 these terminals are
utilized to shut the unit down in case of fl ame failure.
The two terminals are connected to a lockout control
module located in the control box. This lockout control
module contains a magnetic latch relay that requires
manual reset when de-energized. To reset after fl ame
failure, push and release the momentary contact switch
located on the left jacket panel.
Relay Board
The relay board is located in the control panel. It
provides sequencing of the gas valves and blower(s)
based on the staging controller's input. It also provides
the following time delays for proper unit operation:
• A 10 second prepurge when stage 1 is energized.
• A 30 second pressure switch sequencing delay
when
the blowers switch from low fi re to high fi re. The
delay enables the blower to come up to speed before
the high pressure side of the pressure switch
confi rms proper air fl ow.
These time delays are set within the separate time delay
board connected to the relay board.