System settings, Setback, Purge delay – LAARS M4-Ext - Installation Manual User Manual
Page 24: System run-on, Mini-mod, Alert, A b c d, 0 min, 5 min, Laars heating systems

24
SYSTEM SETTiNgS
Button: MENU/
Settings 1 and Settings 2 menus provide access to adjusting and fine-tuning the system for
enhanced comfort and better fuel savings. The M4-CNC behaves differently based on the
selected Control Modes. See "Startup Settings" on page 16.
----- SETTINGS 1 ----
Setback
0
o
F
Purge Delay 1.0min
System Run-On 0min
Lead Rotation Time
BACK ▲ ▼ SELECT
----- SETTINGS 2 ----
Standby Time 10min
Last Stg Hold 0
o
F
BACK ▲ ▼ SELECT
ALERT
To be able to change the
M4-CNC settings the Program/Run Switch must be set
to Program. The switch is located under the Enclosure Wiring Cover for security.
The Enclosure Wiring Cover can be securely closed using a lock.
SETBACk
Adjustable from 0F°/0C° to 75F°/42C°
Default: 0F°/0C°
Button: MENU/
• The Setback feature can be used to provide the M4-CNC with a lower temperature Set Point
when less load is required.
• The lower Set Point will appear on the main display indicating this condition.
• For example, if the calculated temperature is 180°F and the Setback is 20°F, then when in
Setback or Night Schedule, the M4-CNC will hold a Set Point of 160°F = 180°F- 20°F. See
"Day/Night Schedules" on page 28.
• A typical use for Setback is to provide less system temperature to a building during the
Night Schedule or on the weekends when the building is not occupied, but heat is still
required.
• The amount of Setback selected is subtracted from the Set Point when a Setback Input
Signal is received or the Night Time schedule setting started.
• If Setback is selected as the Shutdown/Tstat/Setback Mode (See "Shutdown/Tstat/Setback
Mode" on page 19), the Setback will not be activated unless a Short dry-contact signal is
received on terminals (31 and 32).
• If Shutdown or Tstat is selected as the Shutdown/Tstat/Setback Mode (See "Shutdown/Tstat/
Setback Mode" on page 19), the Setback will be activated only when the Night Schedule time
has started.
SYSTEM
A
B
C
D
Full Modulation Sequencing Control
1 2
RUN
PROGRAM
FOR ALL CIRCUITS
120VAC, 6A RESISTIVE
OUTPUT RATINGS:
1A PILOT DUTY, 15A TOTAL
115VAC 60Hz , 12VA MAX
INPUT RATINGS:
USE COPPER CONDUCTORS ONLY
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
3 4 5 6 7 8 9 10 11 12
13
15
14
17
16
18
22
20
19
21
24
23
29
25
27
26
28
32
30 31
L N
-
+
+
T
T
O
O
RS-485
mA
GND
VLT
SYS
A
B
C
D
PWR
CUR / VLT
A
-
+
+
mA
GND
VLT
-
+
+
mA
GND
VLT
-
+
+
mA
GND
VLT
+
mA
TEMP
OUTDOOR
O
O
TEMP
SYSTEM
EXTENSION
MODULE
CUR / VLT
B
CUR / VLT
C
CUR / VLT
D
CAUTION
: RISK OF ELECTRIC SHOCK
More than one disconnect switch may be required
to de-energize the equipment before servicing.
PROVE
/DHW
SHUTDOWN
/TSTAT
/SETBACK
ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
Mini-MOD
------- SETBACK -------
5
o
F
[
]
BACK ▲ ▼ SAVE
ALERT
When using Soft-Off and Last
Stage Hold, the last boiler
stage will not turn off until both
parameters have elapsed. In
this case, Soft-Off will start after
the Last Stage Hold.
PURgE dELAY
Adjustable from 0.0min to 10.0min
Default: 1.0min
Button: MENU/
• Many boilers go through a purge cycle before they are brought on line. When the M4-CNC
activates a boiler, it does not start to calculate its output until the Purge Delay is over. This
allows the boiler to fully come online and begin producing output.
• The Purge Delay helps prevent short cycling of any newly activated burner. Once the
burner is activated, it MUST run through the entire Purge Delay period.
• The minimum Purge Delay setting MUST be set to the time required by the boiler
manufacturer. Time entry is in 0.1 of a minute (i.e. 1.5min will equal 90 seconds.)
• The Message Display Line will display Purge Delay and the amount of Purge remaining.
--- PURGE DELAY ---
1.0 min
[
]
BACK ▲ ▼ SAVE
ALERT
Set Purge Delay as per boiler
manufacturer recommendation.
SYSTEM RUN-ON
Adjustable from 0min to 360min
Default: 0min
Button: MENU/
• The SYS relay will energize whenever the outdoor temperature is below the Outdoor Cutoff
and the Shutdown is Open or the Tstat is closed. When the Outdoor temperature rises 2°F
above the Outdoor Cutoff or the control is switched to Summer and after the last burner
relay has de-energized, the SYS relay will remain energized for the System Run-On period.
-- SYSTEM RUN-ON --
5 min
[
]
BACK ▲ ▼ SAVE
LAARS Heating Systems
HT# 059104-00 B