LAARS M4-Ext - Installation Manual - Manual (Page 15)

Page 15 LAARS Modulating Controls M4 & M4-EXT
SELECTING THE MODULATING MODE
Normal, Parallel Default: Normal
Button: MENU/<System Startup>/..../Modulating Mode
•
Some boilers run more efficiently as their modulation increases. For these units, it is
more energy efficient to run one unit in high than several units at lower modulation. If
your units are of this type, select Normal. This is the recommended setting for typical
steel and cast iron boilers.
• There are some units that run more efficiently at lower modulation. If it is more energy
efficient to run several units at lower modulation than one at high, select Parallel. This is
typically used on copper boilers, low mass boilers, or burners with high turndown ratios.
BACK SAVE
------ MODULATION MODE ------
Normal
Parallel
BACK SAVE
----- PROVE/DHW SHARING ----
Prove
DHW Without Priority
DHW With Priority
PROVE/DOMESTIC HOT WATER (DHW)
Prove, DHW Without Priority, DHW With Priority Default: Prove
Button: MENU/<System Startup>/..../Prove-DHW Sharing
•
Input Terminals 29 and 30 can be used with either of the above features.
• When Prove is selected, the M4 will not start any boiler stage unless Prove terminals are
connected.
• Using those terminals to connect to an aquastat for a Domestic Hot Water call and selecting either of the DHW options will
raise the calculated water temperature to the lower of 200°F or Max Water Temperature.
• Domestic hot water without priority allows the SYS relay, mostly controlling a primary system pump, to remain energized
during a domestic hot water call (aquastat call on terminals 29 and 30). In Summer or when outdoor temperature is above
Outdoor Cutoff, a DHW call will energize the SYS relay. After the DHW call termination, the SYS relay will continue to run
for the System Run-On period before turning off.
• However, domestic hot water with priority de-energizes the SYS relay during a domestic hot water call (aquastat call on
terminals 29 and 30) for a period of one hour. If after the hour period the DHW call still exist, the SYS relay will energize and
the M4 will continue in the higher temperature setting until the domestic hot water call has terminated.
BACK SAVE
--------- SETBACK MODE --------
Day/Night Schedules
External Signal
SETBACK MODE
Day/Night Schedules, External Signal Default: Day/Night Schedules
Button: MENU/<System Startup>/..../Setback Mode
•
The M4 has two levels of heat, a normal/day and a setback/night. The Normal is good
for when buildings are occupied and people are active. The Setback/Night holds a lower
system temperature and is for when buildings are unoccupied or inactive.
• The Day/Night Schedules provides the user with a Day Time setting for Normal operation and a Night Time setting for Setback.
• The External Signal option switches the M4 to Setback mode when an external signal is received through the Setback terminals.
This allows the M4 to be managed by an external device or control to provide setback.
BACK SAVE
---------- BOOST MODE ---------
30 Minutes
Disabled
BOOST MODE
30 Minutes, Disabled Default: 30 Minutes
Button: MENU/<System Startup>/..../Boost Mode
•
If you do not want a Boost simply select Disabled from the Boost Menu.
• Boost is only available if Day/Night Schedules is selected as a Setback option.
• The morning Boost is designed to return the building to comfortable ambient temperatures after the cooler Night (Setback)
period. The M4 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.
BACK SAVE
--------- SENSOR FAULT --------
All Off
All On
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 are set to Auto
when a sensor reads Short or Open.