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 19. If the manifold pressure is
off by more than 5% adjust it according to steps 1
through 4 above.
Airflow Adjustment
1. Remove the upper front jacket panel.
2. Connect both sides of a manometer to the pressure
switch tee, Figure 18, going to one of the pressure
switches.
3. With the unit operating at high fire the differential
pressure should be between 0.6 and 0.8 in, 15 and
20 mm W.C. Do not change air pressure in lower
stages.
4. To fine tune the air settings once the upper front
jacket panel is installed, remove the plastic plug(s)
on the upper front jacket panel. Use a Phillips
screwdriver to rotate the screw(s) to obtain the CO
and CO readings in the INPUT RATE section above.

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 efficient
trouble-free operation of the boiler. Mount the thermostat
to an inside wall at a height approximately five feet
above the floor. 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 operating control on the water heater is set to its
lowest setting when the water heater leaves the factory.
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!
LCD INSTALLATION AND OPERATION INSTRUCTIONS
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 black rubber plug
in the front top jacket panel.
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 flow switch is provided in the water outlet piping to
prevent the boiler/water heater from firing without
adequate water flow through the heat exchanger.
Low Water Cutoff
If the boiler is to be installed above radiation or if
2
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. Test in accordance with
the manufacturer's instructions included with the
device(s).
Flame Sense Module
The flame sense module is located in the control box.
It is an intermittent pilot control device that controls the
pilot gas flow, spark energy to ignite the pilot gas and
the main valve(s) once pilot ignition has been proven.
Two flame failure alarm terminals are provided on the
flame sense module. For CSD-1 these terminals are
utilized to shut the unit down in case of flame 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 flame
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 7 second prepurge when stage 1 is energized.
• A 7 second pressure switch sequencing delay when
the blowers switch from low fire to high fire. The
delay enables the blower to come up to speed before
the high pressure side of the pressure switch
confirms proper air flow.
These time delays are set within the separate time delay
board connected to the relay board.