MODU-FIRE® Forced Draft Gas-Fired Boiler
42
6.1.2 Terminal Block Assignments – Low Voltage Circuit (LV)
Terminal Number
Label
Description
1
Enable / Disable
Boiler Enable, Contact Closure.
DO NOT ENERGIZE.
2
3
Auxiliary Low Water Cutoff External Limit, Contact Closure.
DO NOT ENERGIZE.
4
5
Start Interlock
External Limit, Contact Closure.
DO NOT ENERGIZE.
6
7
Outdoor Temp Sensor
Outdoor Temperature Sensor Circuit
8
9
DHW Stat or Sensor
Domestic Hot Water Thermostat (contact closure) or Tem-
perature Sensor
10
11
Header Temp Sensor
Header Temperature Sensor
12
13
DHW Flow Switch
Domestic Hot Water flow switch (contact closure)
14
15
0-10V Analog Input
0-10VDC Remote Control Input
16
0V Analog Input
0VDC Remote Control Common
17
For Future Use
Not Used
18
For Future Use
Not Used
19
MODBUS® COM 1A
MODBUS® connection to boiler
20
MODBUS® COM 1B
21
CASCADE A TO A
Cascade connection between boilers
22
CASCADE B TO B