Wiring, Warning, Page 9 laars modulating controls m4 & m4-ext – LAARS M4-Ext - Installation Manual User Manual
Page 9: Wiring the power (terminals 1, 2), Wiring the sensors, Wiring the shutdown (terminals 31, 32)
Page 9
LAARS Modulating Controls M4 & M4-EXT
WIRING
WIRING THE POWER (TERMINALS 1, 2)
•
Bring the 120VAC 60Hz power wires through the bottom Knockout of the enclosure.
•
Class 1 voltages must enter the enclosure through a different opening from any Class 2 voltage wiring.
•
Connect the hot line to terminal marked L.
•
Connect the neutral line to the terminal marked N.
•
LAARS recommends installing a surge suppressor on the power source to the M4.
WARNING
Class 1 voltages must enter the enclosure through a different opening from any Class 2 voltage wiring.
LAARS recommends installing a surge suppressor on the power source to the M4.
1 2
L N
PWR
Line
Neutral
120VAC
Power Source
WARNING
Connect the shield at the control terminal end and cut the shield wire at the sensor
29
25
27
26
28
3
T
T
O
O
TEMP
OUTDOOR
O
TEMP
SYSTEM
Sy
stem
S
ensor
Se
nsor
Shi
led
PROVE
/DHW
WIRING THE SENSORS
SYSTEM SENSOR WIRING (TERMINALS 27, 28)
•
A M4 must be connected to a temperature sensor located in the common header.
•
The M4 is designed to be connected to a HT #904015-00 temperature sensor for immersion in a 3/8ID well (HT
#350147-00 or equivalent). Contact the factory for additional temperature sensor options.
•
Temperature sensor wires can be extended up to 500’ by splicing shielded 2-conductor cable (Belden #8760 or
equivalent).
•
Temperature sensors have no polarity. Connect the two wires from the sensor to the M4 terminals marked
SYSTEM TEMP 27, 28.
•
Connect the sensor shield to the circled terminal 28 with one of the sensor wires.
OUTDOOR SENSOR WIRING (TERMINALS 25, 26)
•
When Outdoor Reset is selected, the M4 will vary the system Set Point based on outdoor temperature.
•
Whether in Set Point or Outdoor Reset modes, the outdoor sensor can be used as an Outdoor Cutoff.
The M4 will disable all Boilers when the outdoor temperature is above the adjustable Outdoor Cutoff
temperature. This feature will automatically be activated when an outdoor sensor is connected.
•
For an outdoor sensor use a LAARS outdoor sensor (HT #904015).
•
The sensor wires can be extended up to 500’ using shielded 2-conductor cable (Belden #8760 or equivalent).
•
Temperature sensors have no polarity. Connect the wires from the outdoor
sensor to the M4 terminals marked OUTDOOR TEMP - 25, 26.
•
Connect the shield to the circled terminal 26 with one of the sensor wires.
29
25
27
26
28
3
T
T
O
O
TEMP
OUTDOOR
TEMP
SYSTEM
Ou
tdoo
rS
e
nsor
S
en
s
or
Shi
led
PROV
/DHW
WIRING THE SHUTDOWN (TERMINALS 31, 32)
•
This feature can be used whenever it is desirable to turn off the M4 stage outputs from a remote location or
another controller (i.e. EMS input).
•
When the Shutdown feature is enabled by closing a dry contact, all active boilers will immediately modulate
down to low then off. The lead boiler will remain in low for a Soft-Off period; default setting is 45 seconds,
and then turn off.
•
The System Output relay will remain active until the System Delay is over and then it will turn off.
•
The Shutdown signal must be a dry contact only. No voltage can be placed across the SHUTDOWN terminals.
•
Bring the two wires from the dry contact to the terminals marked SHUTDOWN- 31,32.
29
28
32
30 31
O
O
O
MP
STEM
Shutdown
Signal
PROVE
/DHW
SHUTDOWN
/SETBACK