Thermal Solutions EVS SERIES Installation, Operating And Service Instructions page 50

Product Features
Boiler Sequence (Continued)
Pre-Sequence States
BOILER
CONTROL MODE
STATE
LCD Display
LCD Display
Any Mode
Boiler
(Except for
Disabled
Remote Control)
Warm Any Mode
Weather (Except for
Shutdown Manual Mode)
Lockout Any Mode
Outlet Sensor &
Local SP Mode
Remote Sensor
& Local SP
Mode
Outlet Sensor &
Remote SP
Standby Mode
Remote Sensor
& Remote SP
Mode
Remote Control
Mode
Manual
Operation Mode
Start/Stop Sequence States
BOILER
CONTROL MODE
STATE
LCD Display
LCD Display
Any Mode
Pump Purge (Except
Manual Mode)
Limit Hold Any Mode
Purge / Pilot
Any Mode
Ignition
Low Fire /
Any Mode
Ignition
Main Ignition Any Mode
Low Fire
Any Mode
Hold
Boiler
Any Mode
Running
Fan Post
Any Mode
Purge
Pump
Any Mode
Cooldown
Sage Boiler Control Instruction Manual
Boiler is prevented from starting, Remote On/Off (Enable) (Terminal RO) Input is not
energized.
Boiler is prevented from starting, Warm Weather Shutdown (WWSD) is enabled and
outside air temperature is above the WWSD Setpoint.
Boiler is prevented from starting, Flame Safeguard lockout is present. A Flame
Safeguard manual reset is required.
Control monitors boiler outlet temperature, a Call For Heat is initiated when boiler
outlet temperature is below the Operational Setpoint.
Control monitors Remote System Temperature, a Call For Heat is initiated when
Remote System Temperature is below the Operational Setpoint.
Control monitors boiler outlet temperature, a Call For Heat is initiated when boiler
outlet temperature is below the Remote Setpoint Input (Terminal C+,C- or Modbus
Interface).
Control monitors Remote System Temperature, a Call For Heat is initiated when
Remote System Temperature is below the Remote Setpoint Input (terminal C+,C- or
Modbus Interface).
Control monitors Remote On/Off (Enable) input (Terminal RO or Modbus Interface), a
Call For Heat is initiated when input is energized.
A Call For Heat is initiated when Manual Mode Menu item Boiler On/Off is set to On.
Once a Call For Heat is initiated and Boiler Pump Purge is selected, the pump output
is energized until the Pump Prepurge Time is complete. If the Call For Heat condition
still exists at the end of the Prepurge Time (the temperature of the water at the sensor
may rise with boiler water flowing passed it) the pump will continue to operate and the
Call For Heat Relay is energized.
Power is applied to the safety limit string. If any limits does not pass power (is not
energized), the alarm LED and LCD display shows the reason the start sequence is
on Hold. Refer to Trouble shooting section for explanation of individual lockout and
alarm messages.
After the limit string passes power, the fan is started, the modulation output is set to
Purge Rate. When the purge period is complete, the flame safeguard sequences on
the ignition transformer and pilot.
When the Spare Input Low Fire is selected, modulation output is set to the Low Fire
Speed when the Spare Input is energized.
The main gas valve input is energized and the modulation output is held constant for
an ignition stabilization period.
The modulation output is held at the Low Fire for the Low Fire Hold time.
When this Low Fire Hold time is complete, the modulation output is released to
modulate.
When water temperature is above setpoint, there is a Flame Safeguard or Limit fault,
the Call For Heat is ended and the modulating output is set to Purge Rate for the Post
Purge Time.
When Boiler Pump Purge is selected, the boiler pump remains "on" until the boiler
outlet temperature is less than the Post Purge Delta (default is 5 F) above the Boiler
Inlet Temperature.
Page 7 of 52
50
Description
Description