Harsco Industrial MACH C1500GG Installation & Owner's Manual page 48

6.1.2 Terminal Block Assignments – Low Voltage Circuit (TB1)
Terminal Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Label
ENABLE / DISABLE
ENABLE / DISABLE
EXTERNAL INTERLOCK
EXTERNAL INTERLOCK
OUTDOOR TEMP
SENSOR
OUTDOOR TEMP
SENSOR
DHW STAT OR SENSOR
DHW STAT OR SENSOR
HEADER TEMP SENSOR Header temperature sensor
HEADER TEMP SENSOR
DHW FLOW SWITCH
DHW FLOW SWITCH
COMMON
0-10V ANALOG INPUT
0V ANALOG INPUT
For Future Use
For Future Use
MODBUS COM 1A
MODBUS COM 1B
CASCADE A TO A
CASCADE B TO B
Description
Boiler Enable, Contact Closure.
DO NOT ENERGIZE.
External Limit, Contact Closure.
DO NOT ENERGIZE.
Outdoor temperature sensor
Domestic Hot Water sensor or thermostat
Domestic Hot Water flow switch
DHW flow switch indicates potable water
flow/usage
Variable Input (VDC) for remote control of boiler
(+)
0V for use with TB1-13 (-)
Not Used
Modbus connection to boiler
Cascade connection between boilers
Page 48
MACH® Gas-Fired Boiler