LAARS S8Ext - Installation Manual - Manual (Page 17)

Page 17 LAARS Sequencing Controls S8 & S8EXT
APPLICATION
Heating-BreakOnRise, Cooling-MakeOnRise Default: Heating-BreakOnRise
Button: MENU/<System Startup>/..../Application
• The S8 offers two application modes, Heating and Cooling. In Heating, the S8 will
sequence stages and when the system temperature is below the set point. In addition,
the system relay will energize when the outdoor temperature is at or below the Outdoor
Cutoff setting.
---- APPLICATION ---
Heat-BreakOnRise
Cool-MakeOnRise
BACK SAVE
• In Cooling, the S8 will sequence stages and when the system temperature is above the set point. In addition, the system relay
will energize when the outdoor temperature is at or above the Outdoor Cutoff setting.
• No Return Temperature monitoring or DHW options will be available in cooling applications.
DHW PIPING (AVAILABLE WITH HEATING ONLY)
Parallel, Primary/Secondary Default: Parallel
Button: MENU/<System Startup>/..../DHW Piping
• When Parallel is selected, the S8 will offer a DHW Priority Timer. The DHW Priority
will only take place during heating periods.
• The Parallel option will allow the DHW Pump relay to energize while de-energizing the
System relay when there is a DHW call during heating. However, during Summer, only
the DHW Pump relay will energize on a DHW call.
---- DHW PIPING ---
Parallel
Primary/Secondary
BACK SAVE
• Selecting the Primary/Secondary option will energize the System relay with the DHW Pump relay whenever there is a call for
DHW even during the Summer or when outdoor temperature is above the Outdoor Cutoff.
IMPORTANT
A DHW call can be initiated by either a dry contact or using a Laars Sensor (CA002400 or
equivalent) for immersion in a 3/8ID well (CA002500 or equivalent). The use of a sensor will allow
the adjustment of DHW Set Point and DHW Differential.
DHW PUMP OUTPUT
No, Yes Default: No
Button: MENU/<System Startup>/..../DHW Pump Output
• The S8 can control the operation of the DHW Pump. This option allows the user to
select if the S8 should be controlling the DHW Pump or not.
--DHW PUMP OUTPUT--
No
Yes
BACK SAVE
COMBUSTION AIR DAMPER OUTPUT
No, Yes Default: No
Button: MENU/<System Startup>/..../Comb. Air Output
• The S8 can control the operation of the Combustion Air Damper. This option allows the
user to select if the S8 should be controlling the Combustion Air Damper or not.
- COMB. AIR OUTPUT-
No
Yes
BACK SAVE
• If Yes is selected, the S8 will energize the Comb. Air relay whenever there is a call for a boiler and will use the Prove input to
check on the status of the Combustion Air Damper. In a failure situation, the message "Wait for Comb. Prove"
will display when there is a call for a boiler stage until Prove is Shorted.
• If Prove fails after boiler stages where energized, the stages will de-energize and the message "Comb. Prove
Failure" will display until situation is rectified.
• If No is selected, the Prove input will be used to check System status instead of the Combustion Air Damper.
SETBACK MODE
Day/Night Schedules, External Signal Default: Day/Night Schedules
Button: MENU/<System Startup>/..../Setback Mode
• The S8 can either utilize its built-in day schedule or an external dry contact signal to
switch to Setback.
--- SETBACK MODE --
Day/Night Schedule
External Signal
BACK SAVE
• If Day/Night Schedules is selected, The Setback will follow the Day/Night Schedule and Shutdown/Setback input (terminals 35
and 36) will be used as Shutdown only.
• The External Signal will allow the Shutdown/Setback input (terminals 35 and 36) to work as an input for Setback. No
Shutdown input will be available in this scenario.