LAARS M4-Ext - Installation Manual - Manual (Page 20)

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• When Shutdown or Tstat is selected, the Day/Night Schedules will be available in the operating menu. See "Shutdown/Tstat/
Setback Mode" on page 19. Terminals 31 and 32 will function as a Shutdown (Turn off boilers when shorted) or as a Tstat (Turn off
boilers when opened). However, a call for DHW will bring the boilers on.
• When Setback is selected, the External Signal option will switch the M4-CNC to Setback mode when terminals 31 and 32 are
shorted. This allows an external device or control to provide the setback signal. No scheduling or boost menu options will be
available with Setback.
BOOST MOdE
(noT AvAiLABLE wiTH EXTERnAL SETBACk inPuT)
30 Minutes, Disabled Default: 30 Minutes
Button: MENU/<System Startup>/..../Boost Mode
• The morning Boost is designed to return the building to comfortable ambient temperatures
after the cooler Night (Setback) period. The M4-CNC will accomplish this by running
elevated water temperatures (will add Setback setting to calculated water temperature) for
30 minutes before the start of the Day schedule setting. That is, if the normal day set point
at a specific outdoor was 145˚F and the Setback setting was 20˚F, the boost will raise the
system calculated temperature to 165˚F for 30 minutes before the start of the Day Schedule
setting.
• If no Boost is needed, then simply select Disabled from the Boost Menu.
• Boost is only available if Shutdown or Tstat is selected as an option. See "Shutdown/Tstat/
Setback Mode" on page 19.
--- BOOST MODE ---
30 Minutes
Disable
BACK ▲ ▼ SAVE
SENSOR FAULT
All Off, All On Default: All On
Button: MENU/<System Startup>/..../Sensor Fault
• The Sensor Fault will determine the operating status of all output stages that has their Mode
set to Auto when a sensor reads Short or Open.
• When All-On is selected, the M4-CNC will turn all boilers On to 100% when the System
reads Short or Open and the outdoor temperature is below Outdoor Cutoff. However, when
the Outdoor reads Short or Open, the M4-CNC will try to maintain the Maximum Water
Temperature.
• When All-Off is selected, the M4-CNC will turn all boilers Off when either the System or
the Outdoor sensor reads Short or Open. However, when the Outdoor reads Short or Open,
the M4-CNC will try to maintain the Minimum Water Temperature.
--- SENSOR FAULT ---
All Off
All On
BACK ▲ ▼ SAVE
ALERT
A good practice after performing any Startup menu modification is to
check all operating settings and adjustments to match the new settings.
SETTiNg THE CONTROL TO FACTORY dEFAULTS
To Reset the M4-CNC control to its original factory defaults, power down the control.
Hold down the two right most buttons while powering the control back up until the
Total Clear Started screen appears. The Display will direct you to the Startup
menu to program the control after the defaults are loaded.
TOTAL CLEAR STARTED
Release buttons
and
Please Wait
NOTE: When resetting the control to original factory defaults all control settings will be overwritten and will no longer exist.
ALERT
Do not turn off power to control until all Startup settings have been made. Otherwise, the next
power-up will be set to many Startup factory settings that might not fit your application.
LAARS Heating Systems
HT# 059104-00 B