13
ADJUSTMENT
There must be sufficient load to operate the boiler at high fire to
perform the following adjustments. Start the boiler and observe
proper operating parameters for the system.
Required Tools:
TORX
®
T40 or 5mm hex wrench
3mm or 7/64in hex wrench
Combustion analyzer
These boilers are equipped with a Honeywell combined gas/air control
and gas safety shut off control valves. The valve functions in parallel
with the variable speed combustion blower to supply the correct gas
air ratio for optimum performance and efficiency. The combustion
blower speed is controlled automatically and determines the amount
of negative pressure experienced by the gas safety shut off/control
valves. The gas/air regulator adjusts gas flow to maintain the proper
pressure at the outlet nozzle of the associated valve.
SETTING OF THE TEST MODE
On UIM go to main menu, scroll down to user settings and press
select. Scroll down to MOD mode, press select. Use the up and
down keys to select options: MIN (MINIMUM FIRING RATE).
MAX (MAXIMUM FIRING RATE). MOD (FOR AUTOMATIC
MODULATION MODE). Press select for the desired option. For
checking the combustion setup on MIN or MAX the boiler will
remain in this state for ten minutes before defaulting to the MOD
(modulation) mode.
HIGH FIRE SETTING
NATURAL GAS
8.5 - 11.0% CO
2
PROPANE
9.5 - 12.0% CO
2
Set boiler to the “Test Mode High,” as described above, to
achieve maximum firing rate of the boiler. Check combustion
readings using a combustion analyzer. If combustion readings
are not in accordance with the chart above adjust the gas
valve as follows: remove the flat, round, blue plastic cap
from the cover. Using a 3mm (7/64”) hex wrench, turn the
adjustment screw counterclockwise to increase or clockwise
to decrease gas flow and achieve the desired CO
2
level. See
Table referenced above for correct settings. There will be a
slight time delay between the adjustment and the response
of the CO
2
measuring instrument. Adjust the settings in small
increments and allow the combustion readings to stabilize
before readjusting. When desired adjustments are complete,
reinstall the blue plastic cap on the cover. Combustion samples
should be taken in the stack within two feet of the boiler.
LOW FIRE SETTING
NATURAL GAS
7.5 - 9.5% CO
2
PROPANE
9.5 - 12.0% CO
2
Set boiler to the “Test Mode Low,” as described above, to
achieve minimum firing rate of the boiler. Check combustion
readings using a combustion analyzer. If combustion readings
are not in accordance with the chart shown above adjust as
follows: remove the cap on the gas regulator using a slotted
screwdriver. This will expose the offset adjustment screw.
Using a TORX
®
T40 or a 5mm hex wrench, carefully adjust
the low fire gas setting to achieve the CO
2
level prescribed
in above reference table.
Note: The rotation of the Low
Fire adjustment is opposite of the High Fire as follows:
Clockwise rotation increases gas flow, counterclockwise
rotation decreases gas flow.
Adjustments to the offset pressure regulators should not exceed
1/4 turn at a time before allowing the readings to respond and
stabilize.
After proper low fire offset adjustment is made, reinstall the slotted
cap on the regulator.
Following all gas valve adjustments, check for proper light-off and
verify correct fuel/air mix and combustion quality throughout the
entire firing range (from lowest to highest fan speed).
CONTROL SYSTEM
The EMC modulation control system is a fully integrated, state
of the art electronic control system. It consists of sensors, output
devices, a power switch, a 24VAC transformer, wiring, and the
following printed circuit boards:
• Modulation Control Board (MCB), see Figure 2.
• Power Distribution Board (PDB), see Figure 2.
• User Interface Module (UIM), see Figure 4.
The MCB contains circuitry for both master control and flame
control. Dip switches on the MCB are used to configure the
system. The User Interface Module (UIM) communicates with the
user through a set of touch pads and a 4-line, 20-character LCD
display. The PDB provides connection points for input power, the
water pump, and the transformer. It also distributes power to the
system and contains the system fuses.
iCOMM ™ & BAC net COMPATIBLE
VF boilers are compatible with the iCOMM ™ remote monitoring
system. The iCOMM ™ system hardware and monitoring service is
purchased separately. It allows users to monitor critical operational,
diagnostic and energy usage data from a secure web site. The
iCOMM ™ system can automatically notify selected personnel via
email and/or cellular phone text messages if operational problems
or user defined Alert Conditions occur.
iCOMM ™ system hardware is compatible with BACnet compliant
supervisory controls and building management systems. For more
information call 888 928-3702.
There are several microcontrollers used on the boards. These control
the temperature and ignition control functions for the boiler. Inherent
in the design are the normal operating sequences and safety features
associated with a gas ignition control system. The system continuously
performs various diagnostic tests to verify proper appliance and
control operation. Should an unsafe condition occur, the control will
shut down the burner and display a red service light as well as indicate
the cause of the error on the display. The operating programs for the
system are stored in permanent memory inside the microcontrollers.
User-selectable operating parameters and a history of detected faults
are stored in rewritable memory in the microcontrollers. A loss of
power does not affect either of the memories.
