Figure 76
Control sequence of operation
ECO control operation
Part number 550-142-190/1218
67
Control features
❏
Blower speed modulation to control the
ECO
boiler’s firing rate.
❏
Advanced PID response to anticipate system needs based on
response to heat input.
❏
Robust text display for ease of operation monitoring and
troubleshooting.
❏
Control of two dedicated inputs for DHW and HEAT
respectively.
❏
Integral outdoor reset option (see page 127).
❏
Dual sensors for boiler outlet temperature and flue temperature,
providing redundant protection.
❏
Low water cut-off, (field wired or optional kit).
❏
Boiler is shipped with an outdoor sensor, allowing outdoor
reset operation for maximum boiler efficiency. See page 127.
❏
Freeze protection and circulator exercising.
Sequence of operation
1. Figure 76 is a summary of the operating sequence for the
ECO
control.
❏
The statuses shown appear in the display as the
ECO
control
cycles the boiler.
❏
The display will flash red if a problem has been detected.
ECO control setup
BEFORE PROCEEDING, perform ESSENTIAL
control settings as instructed on page 69.
1. See Figure 78, page 70 for an overview of the
ECO
control
menus. This page also gives the location of instruction manual
information for each of the main menus.
Display
status
text
Control action
(also see Figure 77, page 68)
POWER
UP
• Check the boiler model listed on the power-up screen.
If it is not correct, turn off the boiler. See page 70 to
change setting.
• When power is turned on, the screen lists sensors that
are detected. If any sensor is not listed, make sure it is
connected correctly. Turn off power and restart.
ODT Sensor
Notice
(Initial
Startup
ONLY)
• If no outdoor temperature (ODT) sensor is detected,
this screen will appear
• Boiler must either use the ODT sensor or be exempt (see
page 127) to operate.
• Non-exempt boilers without a detected ODT sensor
will not operate.
Standby
• Standby — no calls for heat.
• Backlight will turn off due inactivity.
Prepurge
• Call for heat detected.
• Display on with BLUE light (HEAT) or PURPLE light
(DHW).
• Start min./max. on timers if more than one system is
calling — highest priority starts first.
• Start circulators for this priority setup.
• Calculate target temp — If sensor temp is below target
temp, begin firing sequence.
• Blower to ignition speed for prepurge.
Ignition
• After prepurge times out, begin ignition cycle
• Activate gas valve and ignition spark.
• Continue ignition spark for ignition period
• Turn off spark and use electrode to check for flame
signal.
HEATING
• Flame
detected.
• Release boiler to modulation.
• NOTE: If flame is not detected, the gas valve is turned
off, blower turns on (postpurge), and control starts cycle
again. After 5 failures, the control waits 60 minutes,
then tries again.
• If priority timer times out, switch to next priority and
start priority timer.
• If demand satisfied, go to postpurge.
DHW
• Flame
detected.
• Release boiler to modulation.
• NOTE: If flame is not detected, the gas valve is turned
off, blower turns on (postpurge), and control starts cycle
again. After 5 failures, the control waits 60 minutes,
then tries again.
• If priority timer times out, switch to next priority and
start priority timer.
• If demand satisfied, go to postpurge.
Postpurge
• Demand satisfied (temperature reaches target
temperature or limit setting).
• Gas valve off.
• Blower to ignition speed for postpurge.
• Return to standby after purge.
Error/fault
• Display turns RED due to error or limit event.
• Flashing display means lockout condition.
WWSD
• Warm weather shutdown — the boiler will not
be allowed to fire on space heating if the outside
temperature is greater than the WWSD setting. DHW
operation is not affected by WWSD.
Temperature settings
— You must ensure
that the
ECO
control is set for the proper water
temperatures for the system. Excessive water
temperature can cause significant property
damage in some applications.
Multi-temperature systems
— If the
heating system includes circuits that require
lower temperature water (radiant slab circuits,
for example) as well as higher temperature
circuits (DHW, finned tube baseboard, etc.),
it is recommended to protect low-temperature
circuits with limit controls that are wired to
a
ECO
control external limit circuit. Failure
to provide regulation can result in substantial
property damage.
®
S
ERIES
2
G
AS
-
FIRED
WATER
BOILER
—
Boiler Manual
