Central Boiler Fire Star II User manual

Press to
Prime
If Enabled
Press to
Reset
II
OPERATION MANUAL
Save This Manual
For Future Reference
9-JAN-2017 • (p/n 9000317 - REV. D)
For parts and accessories, service or repairs, call your authorized Central Boiler dealer or heating
contractor. Record the information below for future reference.
Serial Number Installation Date
Dealership Name Phone Number
Owner Name
SOFTWARE VERSION 2.5
™
II

by Central Boiler, Inc.
20502 160th Street • Greenbush, MN 56726
CentralBoiler.com • MaximHeat.com
NOTE: Any person(s) operating a hydronic heater must comply with all applicable laws,
including but not limited to local ordinances.
™
II

1
FIRESTAR CONTROLLER (version 2.5)
Press to
Prime
p/n 7000375
If Enabled
Press to
Reset
II
2
4
65
1
3
Before operating the FireStar Combustion Controller,
become familiar with the information the control panel
provides and with the procedures for making changes
to settings. The controller has been programmed with
default settings. If ne-tuning is desired, refer to the
appropriate section of these operating instructions for
more information.
1. The Power button is used to turn the FireStar
combustion controller on and off. To turn the
combustion controller on or off, press and hold the
Power button for at least one second.
When turning the combustion controller off, the
Power button does not disable all electrical
power to the furnace. If the LED display indicates
, the burner auger is “unloading” the fuel and
will run until the re goes out.
2. During normal operation, the LED display indicates
the actual temperature of the system water. Other
information will also be displayed on the LED
display depending on settings, modes, etc. The
Water Temp button may be used to display the
water temperature setting or, used in conjunction
with the and buttons, to change the water
temperature setting.
3. The heat output (fuel feed rate) settings in each of
the three modes (HIGH / MEDIUM / LOW) may
be changed here using the and buttons. During
operation, the light bar will indicate the heat output
setting for the mode the combustion controller is
currently in. The and buttons may also be used
in conjunction with the Air Adjust button to
change the air setting for each mode. By default, the
LOW mode is disabled.
4. The AirAdjust button may be used in conjunction
with the HIGH, MEDIUM and LOW and
buttons to change the combustion air ow setting
for each mode. For HIGH and MEDIUM modes,
decreasing the setting (fewer lights on the light
bar) lowers the fan speed and increasing the setting
(more lights on the light bar) increases the fan speed.
For LOW mode, increasing or decreasing the setting
will increase or decrease the length of time the fan
operates each time the auger turns.
5. Press the Auger button once to start the prime
function. This will cause the augers to operate for
30 seconds while the LED display counts down the
time. When pressed twice within one second, Clean
Out Mode is enabled. During Clean Out Mode, the
transfer auger (top auger) is disabled. The Auger light
is on any time the burner auger is running.
6. The Reset button can be used to reset the ignition
mode (for example, if there is an alarm, you can
press this button to restart the ignition sequence).
Adjusting Water Temperature Setpoint
Normally the furnace water temperature will be
displayed. To display the water temperature setpoint,
press the Water Temp button. The default setting is
175˚C (79˚C). To raise or lower the water temperature
setpoint, press and hold the Water Temp button;
then press the and button. The water temperature
setpoint can be set between 150˚F (65˚C) and 190˚F
(88˚C).
NOTE: To reduce condensation in the rebox, it
is not recommended to set the water temperature
setpoint below 165˚F (74˚C).
Burner Temperature
To display the temperature of the burner, press the
Water Temp button. The LED display will indicate
the actual temperature of the burner up to 999 degrees
or, if higher, as a decimal representation (e.g., 1500˚F
will display as 1.50).

2
Initial Start-up
NOTE: Before starting the outdoor furnace,
make sure that (1) the proper amount of 1650XL
Inhibitor Plus has been added and the water level
is full; (2) there is adequate clean, dry fuel in the
hopper or supply bin; (3) the main electrical power
supply to the outdoor furnace is on; and (4) the
ground rod has been installed and connected to
the outdoor furnace.
CAUTION
Do not burn garbage, gasoline, naphtha, drain oil
or other inappropriate materials.
1. Press the Power button. Upon startup, the
combustion controller will display the software
version number followed by a brief indicator light
test. The LED display will indicate the furnace water
temperature.
2. Fuel must be present in the burn chamber for the
system to burn properly. To deliver fuel to the
burn chamber, start the prime cycle by pressing
the Auger button. The prime cycle timer will
count down and stop the augers. When starting
from an empty auger, it may take two prime
cycles.
NOTE: Upon initial start-up, it is not uncommon
for a substantial amount of condensation to be
present in the rebox as the furnace is coming up
to operating temperature. This is normal and the
moisture will evaporate when the outdoor furnace
reaches operating temperature. Condensation
can also occur if the furnace is allowed to operate
below 140˚F (60˚C) on a normal basis.
CAUTION
Regularly exposing the furnace rebox to
excessive condensation can signicantly reduce
the life of the rebox.
Normal Operation*
FireStar Controller - Maxim M255 PE
Burner Modes
*NOTE: This graph is based on factory default settings when the water temperature setpoint is 175˚F.
175˚F
-10°F
-10°F
+7°F
+13°F
165˚F
Water Temperature
155˚F
STANDBY
10 Minute Minimum
If burner temperature is not high enough the controller will not switch from MEDIUM to HIGH mode.
5 Minute Minimum
STANDBYMEDIUM MEDIUMHIGH
162˚F

3
Setting the FireStar Controller for Fuel Type, Heat Load and Efciency
The controller’s default settings allow the furnace
to operate properly in most installations without
adjustment. These settings can be adjusted, however, for
installations that require matching the furnace output to
the heat demands of the system.
NOTE: Be sure to thoroughly read and understand
this manual before making changes to default
settings. Changing settings can signicantly
change the way the furnace operates. Consult
your dealer if you have any questions.
Corn Mode
By default, the combustion controller is set to burn
premium quality wood pellets. Several variables in the
Setup Mode are set by default automatically to optimize
operation of the Maxim with wood pellets.
When the combustion controller Fuel Mode (variable
7) is set to corn, several variable settings will change
automatically as will the ignition sequence. These
changes are to optimize operation of the Maxim with
corn. Also note the following changes when selecting
corn mode:
NOTE: If corn mode is selected, it is recommended
that a second ignitor be installed. Both ignitors
will stay on while there is a call for heat. When
burning corn, it is also recommended that 3
sections of chimney are installed.
• The LED display will alternate between water
temperature and burner temperature
• The Auger On Time for MEDIUM and HIGH
modes is reduced from 3 seconds to 1 second
• Ignition Sequence Ramp-up for Corn Mode:
1. Flashes one green bar until the burner
temperature reaches 300˚F.
2. Flashes four orange bars until the burner
temperature reaches 400˚F.
3. Flashes one red bar until the burner
temperature reaches 850˚F for three minutes.
4. At this point, the combustion controller goes
to the normal setting.
NOTE: If the burner temperature drops below 300˚F
for several minutes, the combustion controller
will begin the ignition sequence again.
Heat Output Settings
For best results, determine the lowest water temperature
setpoint the outdoor furnace can be set to, while still
supplying enough heat to the heat emitters. For most
installations, a water temperature setpoint of 175˚F
(79˚C) should be adequate.
If, as an example, the water temperature setpoint is
175˚F, when a heat load is applied, there will be a delay
before the water temperature starts to fall. When it falls
10˚F, the combustion controller will shift to MEDIUM
mode. If the heat output in MEDIUM mode is unable
to maintain the water temperature with the heat load
applied, once the water temperature drops another
10˚F (this variable is called the MEDIUM to HIGH
differential) and the burner temperature is high enough,
the combustion controller will shift to HIGH mode.
NOTE: The Maxim operates most efciently at
about 50% of its output capacity. If the combustion
controller is shifting to HIGH mode, increasing
the MEDIUM to HIGH differential (see variable 3 in
Setup Mode) will keep the combustion controller
in MEDIUM mode longer and may save fuel.
NOTE: A short drop in water temperature is
normal as it can take some time for the outdoor
furnace to start to gain temperature.
NOTE: The combustion controller will operate
in MEDIUM mode for a minimum of 5 minutes
before shifting into HIGH mode, regardless of
temperature loss.
If the heat demand is less than 50% of the Maxim’s
output capacity, it is not necessary for the FireStar
combustion controller to shift into HIGH mode.
Increasing the MEDIUM to HIGH differential will
help keep the combustion controller from shifting
unnecessarily to HIGH MODE (see Setup Mode
section).
Monitor the outdoor furnace operation to determine if
additional changes are needed, keeping in mind that
it may take several cycles of the heat load before this
becomes apparent.

4
Understanding Operating Modes
LOW Mode (If Enabled)
NOTE: LOW mode should only be enabled if there
is a problem with the electric ignitor. Contact your
dealer to enable LOW mode. LOW mode should
be disabled once the problem has been solved.
LOW mode is used to maintain the re when the heat
demand is low or not present.
NOTE: For most applications, the LOW heat
output and air settings should be set to the
lowest setting when using wood pellets. The
LOW heat output and air settings may require
additional adjustment if the re does not relight
when shifting from LOW to MEDIUM, or if the
outdoor furnace overheats when changing to a
lower mode.
• The LOW heat output setting should be set as low
as possible while still enabling the re to relight
when shifting into MEDIUM mode.
• If there is no fuel left in the burn chamber and the
re has gone out, the heat output is set too low.
Increase the LOW heat output setting.
• If the water temperature increases above 195˚F
(90˚C) when the furnace is in LOW, the heat
output is set too high. Decrease the LOW heat
output setting.
Monitor the outdoor furnace operation to determine if
additional changes are needed, keeping in mind that
it may take several cycles of the heat load before this
becomes apparent.
IGNITION Mode
Upon entering ignition mode, the augers will start for
several seconds to add enough fuel to the burner. The
fan will then speed up to the ignition fan speed and the
ignitor will heat up. If the ignition sequence exceeds
ten minutes, the augers will start a second time to add
more fuel to the burner. The controller will attempt this
ignition sequence three times.
Corn Only - Ignition Ramp Up Mode
When the combustion controller is set to corn mode,
there is an additional function that slowly raises the
feed rate until it reaches the actual MEDIUM feed rate.
The lower feed rate will be in effect until the burner
temperature is above 850˚F (454˚C) for at least three
minutest. The MEDIUM Mode LEDs will be ashing
during this time.
MEDIUM Mode
In general, the MEDIUM heat output setting should
be set high enough to minimize the amount of time the
controller is in HIGH mode. Increasing the MEDIUM
to HIGH differential will also keep the combustion
controller from shifting to HIGH mode.
The outdoor furnace is most efcient when it is operating
in MEDIUM mode and not shifting often into HIGH
mode. The combustion controller changes to MEDIUM
mode when the water temperature drops 10˚ below the
water temperature setpoint. MEDIUM mode represents
20%-60% of the outdoor furnace’s heat output capacity.
NOTE: For most applications, the default MEDIUM
heat output setting is adequate to allow the
outdoor furnace to operate efciently. For some
heat load requirements or when burning a fuel
other than wood pellets, it may be necessary to
change this setting.
• If the outdoor furnace operates in HIGH mode
much of the time, increase the MEDIUM heat
output setting one step. If the outdoor furnace
changes from MEDIUM to LOW mode when
there is a heat demand, lower the MEDIUM heat
output setting one step.
• In a higher heat load installation such as radiant
oor heat, an abrupt heat load change (i.e., when
there is no longer a call for heat) will cause the
combustion controller to shift quickly from HIGH
to MEDIUM to LOW mode. A fuel such as wood
pellets that burns easily will continue to provide
heat in LOW mode and can cause the water
temperature to increase above 195˚F (90˚C). In
this instance, decrease the MEDIUM heat output
setting so there is less remaining fuel when the
controller changes from HIGH to LOW mode.
• Upon entering MEDIUM mode, the combustion
controller will turn the fan on in its highest setting
for a few seconds to clear the burner. It will then
slow down to its medium speed. If the burner
temperature is high enough, the controller will
stay in medium and cycle the augers at the medium
feed rate.
• If the burner temperature is too low, the ignition
sequence will start.

5
HIGH Mode
The reason the FireStar combustion controller has a
MEDIUM and HIGH heat output setting is for efciency.
The most efcient setting for the HIGH mode is when
the heat output setting is set as low as possible while
still providing enough heat.
HIGH mode is used for peak or spike heat loads. The
combustion controller changes to HIGH mode when
the water temperature drops 20˚F below the water
temperature setpoint (this variable can be changed).
HIGH mode represents 65%-100% of the outdoor
furnace’s heat output capacity.
NOTE: The combustion controller will operate
in MEDIUM mode if the burner temperature
is high enough, for a minimum of 5 minutes
before shifting into HIGH mode, regardless of
temperature loss.
• The most efcient setting for the HIGH heat output
mode is the lowest setting possible that keeps the
water temperature from dropping to 150˚F (66˚C).
If the water temperature drops to 150˚F (66˚C),
increase the HIGH heat output setting or reduce
the heat load. Remember that a thermostatic valve
must be installed in each set of hot supply and
return lines to keep the water temperature from
dropping below 150˚F (66˚C).
• If the fuel cannot burn fast enough (i.e., unburned
fuel gets pushed into the ash pan), either lower the
HIGH heat output setting, raise the HIGH mode
air setting, use a different type of fuel that will
burn better, or mix in premium wood pellets with
the fuel.
To View All Heat Output Settings:
1. Press any of the or buttons for the HIGH,
MEDIUM or LOW modes. The light bars will
display the current heat output settings.
To Change Heat Output Settings:
1. In each mode (HIGH, MEDIUM or LOW), press the
button to increase the heat output or press the
button to decrease the heat output. The new heat
output setting will be displayed on the light bar.
2. The light bars will turn off and the new heat output
setting(s) will take effect 5 seconds after no buttons
are pressed.

6
Air Settings
Air Settings When LOW Mode is Enabled
The air setting for LOW mode increases or decreases
the length of time the fan runs each time the auger turns.
NOTE: The LOW heat output and air settings
should only require adjustment if the re does
not relight when shifting from LOW to MEDIUM.
• If there is fuel left in the burn chamber, the water
temperature has not increased above 195˚F (90˚C)
and the re has gone out, the air setting for LOW
mode is too low. Increase the air setting for LOW
mode.
Air Setting for MEDIUM and HIGH Modes
The air settings for the MEDIUM and HIGH modes can
be adjusted to provide the correct amount of combustion
air to the re. The proper setting for these two modes is
the lowest setting that will still provide enough air for
complete combustion (i.e., no smoke and no unburned
fuel in the ash pan). If the air settings are too high, the
extra air will take heat with it as it goes out the chimney.
If the air settings are too low, complete combustion may
not occur.
As a general rule, the fan setting for the MEDIUM
mode should be within one bar of the MEDIUM heat
output setting. The fan setting for HIGH mode should
be within one bar of the HIGH heat output setting.
To optimally set the air setting for the MEDIUM and
HIGH modes, it is best to use a CO2combustion meter
and adjust for a reading of 11-13%. If a CO2combustion
meter is not available, set the air setting for each mode to
the lowest setting that does not cause smoke to appear in
the exhaust after the mode has operated for 15 minutes.
NOTE: In cold weather, steam in the exhaust will
condense and appear as smoke, similar to the
steam in the exhaust from an automobile.
To View the Current Air Settings:
1. Press and hold the Air Adjust button. The light
bars will display the current air setting for each
mode.
To Change the Air Settings:
1. Press and hold the Air Adjust button; then
press the or button for the respective mode
to decrease or increase the air setting. For HIGH
and MEDIUM modes, decreasing the setting (fewer
lights on the light bar) lowers the fan speed and
increasing the setting (more lights on the light bar)
increases the fan speed.
2. Release the Air Adjust button.
NOTE: Allow the re in the burn chamber to
stabilize for a few minutes after changing an air
setting to assess what effect the change had
before making another adjustment.

7
Ignition / Clean Out Mode
Ignition
The combustion controller continuously monitors the
burner temperature when in MEDIUM mode and there
is a call for heat. If at any time the burner temperature
is less than the burner temperature setting (which is
set to a default setting), the combustion controller will
automatically start the ignition sequence in an attempt
to relight and raise the burner temperature.
If after three ignition cycles, the burner temperature does
not rise above the burner temperature setting, all outputs
will be disabled and the LED display will indicate
to show that the ignition attempt has failed.
This will continue until the cause of the Fire Out alarm
is corrected and the controller is reset. To clear the
Fire Out alarm, turn the combusiton controller off and
on again or press and hold the Reset button. This
will reset the combustion controller and allow normal
operation.
NOTE: Before resetting the controller from
nd the cause of the burner not being operational
(e.g., out of fuel, wet or contaminated fuel,
mechanical problem, etc.).
Clean Out Mode
Situations may arise when it becomes necessary to
empty all of the fuel from the burner auger (e.g., for
service, at the end of season, etc.). In the Clean Out
Mode, the transfer auger is disabled.
To start Clean Out Mode:
1. Press the Auger button two times within one
second. The Clean Out Mode light will turn on,
the transfer auger will be disabled, the combustion
controller will shift into MEDIUM mode, and the
LED display will indicate . The combustion
controller will stay in MEDIUM mode with the
transfer auger disabled for 2 hours unless it is
cancelled.
NOTE: The combustion controller will not go into
Fire Out mode when Clean Out Mode is enabled.
It is the operator’s responsibility to visually
check the burner auger area to determine that
all of the fuel has been cleared and consumed.
The combustion controller can then be powered
off and main power disconnected to the furnace
before performing service.
To cancel Clean Out Mode:
(1) Turn the controller off and then on again, (2) press
the Auger button two times within one second, or (3)
press and hold the Auger button to prime. The Clean
Out Mode light will turn off and the burner and transfer
augers will run as normal.
NOTE: If not cancelled, Clean Out Mode will run
for 2 hours. After 2 hours the Clean Out Mode
light will turn off and the burner and transfer
augers will run as normal.

8
LED Display Alarm Denitions
If any of the following alarms occur, system operations
will be halted until the cause of the alarm is corrected.
Low Water: the LED display will ash
until the water level is above the sensor. Check
that the water level indicator rod is above the
vent cap and, if necessary, add water according
to the Water Quality and Maintenance section.
If adding water does not correct the problem,
contact your Central Boiler dealer.
High Water Temperature: the LED display will
alternately ash and the water temperature
if the water temperature reaches 200˚F (93˚C).
The LED will continue to alternate between
and the water temperature until the water
temperature drops to 195˚F (90˚C).
If this alarm occurs often, you will need to lower
the water temperature setpoint.
There is an external limit switch that can also
lock the controller in the high water temperature
alarm. The LED display will alternately ash
and the water temperature if the external
limit switch trips. This limit switch will trip at
approximately 200˚F (93˚C) and automatically
reset at 165˚F (74˚C).
If this alarm occurs often, you will need to lower
the water temperature setpoint.
Back Burn: The LED display will ash
if the combustion controller detects a high
temperature in the burner auger area, even if the
control panel is turned off. Everything but the
burner auger will be disabled. The burner auger
will run for two minutes, pause for 10 minutes,
and continue as required until the combustion
controller detects that the temperature in the
burner auger area has dropped.
Fire Out: while in MEDIUM or HIGH mode, if
the burner temperature drops below the burner
temperature setpoint and, if enabled, the ignitor
has tried to relight the re three times, the
combustion controller will go into Fire Out mode
and the LED display will ash . This will
continue until the cause of the Fire Out alarm is
corrected and the combustion controller is reset.
To clear the Fire Out alarm, turn the combustion
controller off and on again or press and hold the
Reset button. This will reset the combustion
controller and allow normal operation.
NOTE: while in LOW mode, if the burner
temperature drops below the burner temperature
setpoint, the LED display will not ash .
Instead, the bottom three LED lights in the heat
setting bars will ash and augers will be disabled
until the water temperature drops low enough for
the combustion controller to change to MEDIUM
mode. No action is required.

9
Setup Mode
To Enter Setup Mode
Press and hold the Water Temp button for at least 7
seconds until the LED display changes from the water
temperature to .
Changing Control Variables
While in Setup Mode, select the control variable you
want to change (see Selecting Control Variables). To
make a change, press the Water Temp button. The
current value is displayed. Press the or the button
to modify the setting. Press the Water Temp button
to accept the value and return to the selection menu.
Selecting Control Variables
Variables 1-7 and 18-21 can be changed within Setup
Mode. Variables 8-17 are reserved settings that are used
in conjunction with the optional FireStar XP.
To select a variable while in Setup Mode, press the Water
Temp or button until the number representing
the variable appears in the display. The following list
indicates each variable’s number, name, the default
setting and a brief description of the function.
1. Water Temperature Setpoint: 175˚F (80˚C)
The water temperature the combustion controller
will operate to maintain. Range: 150-190
2. IDLE/STANDBY to MEDIUM Differential: 10˚F (6˚C)
When the water temperature is less than the Water
Temperature Setpoint minus this setting, the
combustion controller will change from IDLE/
STANDBY mode to MEDIUM mode. For example,
with the default settings, the combustion controller
will change from IDLE/STANDBY mode to
MEDIUM mode when the water temperature is less
than 175˚F – 10˚F (or 165˚F). Range: 1-20
3. MEDIUM to HIGH Differential: 10˚F (6˚C)
When the water temperature is less than the Water
Temperature Setpoint minus the LOW to MEDIUM
Differential minus this setting, the combustion
controller will change from MEDIUM mode to HIGH
mode. For example, with the default settings, the
combustion controller will change from MEDIUM
mode to HIGH mode when the water temperature is
less than 175˚F – 10˚F – 10˚F (or 155˚F). Range:
1-30
NOTE: Changing this variable will automatically
change the HIGH to MEDIUM differential. The
HIGH to MEDIUM Differential is a ratio of the
MEDIUM to HIGH Differential and is a numeric
value from 1 to 10. When the water temperature
is this far above the temperature at which the
combustion controller changed into HIGH mode,
the combustion controller will change to MEDIUM
mode.
4. Ignition Burner Temperature: 300˚F (149˚C)
The combustion controller will operate in Ignition
Mode until the burner temperature reaches this value
plus the Ignition Differential (variable 5).
If the burner temperature drops below this value
during MEDIUM mode, the controller will switch
to Ignition mode. Range: 100-470
5. Ignition Differential: 100˚F (38˚C)
The controller will continue in Ignition Mode until
the burner temperature is higher than the Ignition
Burner Temperature plus this value (300˚F + 100˚F
= 400˚F). If a third attempt is required, this value
is added to the target temperature again (300˚F +
100˚F + 100˚F = 500˚F). Range: 1-199
6. Ignition Duration: 10 min. (wood pellets)
20 min. (corn)
The amount of time in minutes Ignition mode will
run. The combustion controller will make up to three
attempts at ignition, each for this amount of time,
before a Fire Out mode. Range: 1-100
7. Fuel Mode: 1 (wood pellets)
0 (corn)
By default, this variable is set to 1 and the
combustion controller is congured to operate with
premium quality wood pellets as a fuel source. The
combustion controller also has a modied program
to help ignite lesser quality wood pellets and/or corn.
To enable, change this setting to 0. If set to 0, several
other variables will automatically change to the corn
default values. Range: 0-1
18. Technician Use Only: 1
Do not adjust this value.
19. Electric Assist Duration: 0 (wood pellets)
61 (corn)
Time in minutes that the electric ignitor(s) will
remain on after the Burner Temperature has
exceeded 400˚F (variable 4 plus variable 5). Setting
this variable to 61 will keep the electric ignitor(s) on
constantly. Range: 0-61
20. Ignition Prime Duration: 15 (wood pellets)
2 (corn)
The augers will run for this amount of time in
seconds during the rst ignition attempt. Range:
0-255
21. 2nd Ignition Prime Duration: 30 (wood pellets)
1 (corn)
The augers will run for this amount of time in
seconds during the second ignition attempt. Range:
0-255

Central Boiler, Inc.
20502 160th Street
Greenbush, MN 56726
CentralBoiler.com
Printed in U.S.A. ©2017 Central Boiler
(p/n 9000317 - REV. D) • 9-JAN-2017
To Exit Setup Mode
Wait 10 seconds (while not pressing any buttons) and
the controller will automatically exit Setup Mode.
To Lock/Unlock Combustion Controller
The combustion controller can be locked to prevent
unauthorized access to the combustion controller
settings. To lock the combustion controller: Press the
Water Temp button four times within three seconds.
The LED display will indicate (locked) for several
seconds. To unlock the combustion controller: Press the
Water Temp button four times within three seconds.
The LED display will indicate (unlocked) for
several seconds.
Power Outage
In the event of a power outage, the combustion controller
is programmed to return to its previous state. If the
system was powered on, it will automatically restart.
Troubleshooting/System Restarting
If there appears to be a combustion controller error,
attempt to restart the controller using the Power
button. If a standard restart fails to correct an apparent
error, shut off the main power at the source for one
minute and then try again. If that does correct an
apparent error, contact your Central Boiler dealer.
To restore to default settings:
Press the Power button to turn off the combustion
controller; then, while pressing and holding the Water
Temp button, press the Power button to turn
on the combustion controller. The LED display will
indicate if the combustion controller is restored
to default settings.