LAARS M4-Ext - Installation Manual - Manual (Page 17)

Page 17 LAARS Modulating Controls M4 & M4-EXT
• With most baseboard heating applications, a 1.00 (OD):1.00 (SYS) setting is a good
place to start. With a 1.00 (OD):1.00 (SYS) ratio, for every degree the outside
temperature falls, the system water temperature is increased one degree.
• If required: Adjust the RESET RATIO in cold weather. If the ambient building
temperatures are too cold in cold weather, move the ratio to a higher selection. That is,
if 1.00 (OD):1.00 (SYS) was initially selected, change the selection to 1.00 (OD):1.25
(SYS). If the building temperatures are too warm in cold weather, move the ratio to
a lower selection. That is, if 1.00 (OD):1.00 (SYS) was initially selected, change the
selection to 1.25 (OD):1.00 (SYS).
Outdoor Temperature
W
at
er
T
em
per
at
u
re
70 40 50 60
130
120
110
100
1:4 1:1
4:1
Colder
Warmer
OUTDOOR CUTOFF TEMPERATURE
Adjustable Off, 20ºF - 100ºF, On Default: 65ºF
Button: MENU/Set Point/Outdoor Cutoff
in Set Point
Button: MENU/Set Point/Offset/Outdoor Cutoff in
Reset
• If the outdoor sensor is installed, the Outdoor Cutoff screen will automatically appear
after the temperature Set Point has been selected.
• When the outdoor temperature falls to the adjustable Outdoor Cutoff temperature, the M4
will control and modulate Boilers to hold the calculated temperature.
BACK SAVE
------- OUTDOOR CUTOFF -------
65
F
[]
• When the outdoor temperature rises to the Outdoor Cutoff plus a 2°F differential, the M4 will turn all boilers off. The System
relay will remain energized for the Run-On delay then de-energize. The Message Display Line will display Outdoor Cutoff.
• The Outdoor Cutoff can be set from 20°F to 100°F. In addition, the Setting can be set to ON or OFF. In the ON position, the
System Relay will run regardless of the Outdoor temperature (OD) and the burner stages will be active to hold the calculated
water temperature. (Note: The lowest water temperature the M4 will circulate is 70°F. If the Outdoor Cutoff is turned ON and
the Season is set to Winter, the M4 will circulate at least 70°F water even in the hottest of weather.) In the OFF position, the
system pump will always be off and all burner stages will be off.
OFFSET
Adjustable 50ºF - (-50ºF) Default: 0ºF
Button: MENU/Set Point/Offset
in Reset only
• The Offset setting lets you adjust the starting points of the Reset Ratio curves. This
means that, regardless of the Outdoor temperature (OD), or the Reset Ratio that has
been selected, when the Offset setting is changed, that change is directly added to or
subtracted from the calculated temperature. For example, if the Set Point temperature
was 130°F and the Offset was changed from 0° to 10° (an increase of 10°), then the Set
Point temperature would increase to 140°F
BACK SAVE
-------------- OFFSET -------------
+0
F
[]
• The Offset setting does not change the ratio selection. For instance, with 1.00 (OD):1.00 (SYS) Reset Ratio, the System water
temperature (SYS) will always increase one degree for each degree change in the Outdoor temperature (OD). What the Offset
does is add or subtract a constant temperature value. (See Understanding Operation Concept)
• If required: Adjust the Water Offset in mild weather. If the ambient building temperatures are too warm in the mild weather,
decrease the Water Offset. If the ambient building temperatures are too cold in the mild weather, increase the Water Offset. The
rule of thumb for baseboard radiation is to change the Offset 4°F for every 1°F you wish to change the building temperatures.
In radiant heat applications, change the Offset 1°F or 2°F for every 1°F you wish to change the building temperature.
MINIMUM WATER TEMP
Adjustable 70ºF - 180ºF Default: 70ºF
Button: MENU/Set Point/Offset/Outdoor Cutoff/Minimum Water Temp
in Reset only
• The Minimum Water Temperature must be set to the boiler manufacturer’s specification.
The M4 will calculate the Set Point based on the Outdoor temperature (OD), the Reset
Ratio, and the Offset value. The M4 will control all boilers modulation to hold either the
Set Point temperature, or the Minimum Water Temperature, whichever is higher.
• The Minimum Water Temperature must be at least 20°F lower than the Maximum
Temperature (See next setting).
BACK SAVE
--- MINIMUM WATER TEMP ----
70
F
[]