LAARS S8Ext - Installation Manual - Manual (Page 26)

Page 26 LAARS Heating Systems
BOOST PERIOD
Adjustable 0 to 120 minutes Default: 30 minutes
Button: MENU/<System Settings>/Setback/Boost/Boost Period
• This will determine the amount of Boost the system will receive.
• If External Signal was selected as the Setback Mode, the Boost will start when the
------ BOOST PERIOD---
30min
[ ]
BACK SAVE
switch from Setback to normal operation takes place and will continue for the full Boost Period. An example would be if
the Boost Period was set to 30 minutes and the shorting of the Setback terminals has ended at 7:00Am, the Boost will start at
7:00Am and will terminate at 7:30Am where the control will resume normal operation.
• If Day/Night Schedule was seleceted as the Setback Mode, the Boost will start a full Boost Period prior to the switch from
Night Setback to Day normal operation. If the Day was set to start at 7:00Am, the Boost Period was set to 30 minutes, the
Boost will start at 6:30Am and terminate at 7:00Am.
Avoiding Conflicting Boiler Limits
• The temperature limits set on the boilers MUST be set considerably higher than the S8’s
Set Point for the reasons detailed below.
• The S8 sensor is located in a common header some distance from the boilers.
• As the temperature rises in the header and before reaching the sensor location, energy is
dissipated. Therefore, the temperature in the header could be lower than that registered
by boiler sensors.
• In addition to the normal drop experienced between the boiler’s temperature and that
WARNING
The temperature limits set
on the boilers must be higher
than the S8 Set Point. Read
the section at left for details
that will prevent erratic system
operation.
read by the S8 sensor, the Last Stage Hold setting must be accounted for. The boiler limit must be set above the Set Point PLUS
the Last Stage Hold PLUS the normal drop experienced in the piping.
• Using the previous example of a 10°F Last Stage Hold with a 160°F Set Point, the boilers’ limits must be set enough over 170°F
to prevent the boilers’ internal limits being reached. In this situation, the boiler high limit should be set at approximately 180°F
to prevent the difference in boiler temperature vs. header temperature causing erratic operation.
DAY/NIGHT SCHEDULES
Button: MENU/<System Settings>/<Setback Schedule>/Day Schedules
• The S8 has two levels of heat or cool. The Day level is used when a building is
occupied and people are active.
• The Night (Setback) level is used when a building is not occupied, or when people are
sleeping. This setting reduces the calculated temperature in Heating and increase it in
Cooling by the Setback setting. In Heating, if the Day calculated water temperature was
150˚F and the Setback was 20˚F, the Night Schedule will run at (150˚F - 20˚F) = 130˚F.
-- DAY SCHEDULE ----
07:**Am
BACK SAVE
-- NIGHT SCHEDULE --
10:**Pm
BACK SAVE
• If the Boost feature is being used, it uses the Day Schedule as a Boost ending point. That is, if the Day Schedule is set to start
at 6:00AM,the Boost was set to 10ºF, and the Boost Period was 30 minutes, the Boost will start at 5:30AM. The S8 will then
raise the calculated water temperature by the Boost amount. Using the previous example, at 5:30AM the S8 will raise the
calculated water to 160˚F (150˚F + 10˚F) until 6:00AM.
SET PRESENT TIME
Button: MENU/<System Settings>/<Setback Schedule>/Present Time
Button: MENU/<Maintenance>/Present Time
• The Time is used for Day/Night Schedule and History graph.
• Adjust the time by selecting Time from the menu and then scrolling through the hours
followed by the minutes. If hours are to be set to PM, scroll through the AM hours to
reach the PM hours.
- SET PRESENT TIME
**:**
BACK SAVE
CAUTION
Remember that the battery is the backup for the Time. If no power is supplied to the S8 and there
was no battery or battery had no power, time values will be lost and will need to be reset.