Patterson-Kelley MACH C-1500H Installation & Owner's Manual page 30

Cascade Shield & Cascade – TB1-18, TB1-19 and TB1-20 can be used to setup a cascade system
with multiple MACH boilers with NURO controls. Terminals TB1-19 and TB1-20 are reserved for the
cascade communication between the master and member boilers. Terminal TB1-18 should be used to
connect the cascade communication wiring shield between all boilers. The cascade and shielding must
be wired from the master boiler to each individual member boiler in a daisy-chain fashion.
MODBUS COM & MODBUS Shield – TB1-22, TB1-23, and TB1-24 can be used to integrate the boiler
with a Building Management System (BMS), Protocol Converter, or other device capable of RS-485 2-
wire MODBUS communication. Terminals TB1-22 and TB1-23 are reserved for MODBUS and terminal
TB1-18 provides a connection for the MODBUS communication wire shield.
ECOM 1, 2 & 3 – TB1-25, TB1-26, and TB1-27 can be used to connect a wireless outdoor air
temperature sensor. The wireless receiver should be installed at or near the boiler, and the wireless
temperature sensor should be installed on the North face of the building and shielded from direct
sunlight exposure.
Revised: January 3, 2020
Released: January 3, 2020
NOTE Only ground the shield at the master boiler.
NOTE Only ground the shield at the master boiler.
 Patterson-Kelley 2020
All Rights Reserved.
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P-K MACH
Technical Service 1.877.728.5351
1004905981 P-K MACH C1500H-C4000 Installation and
Owners Manual (Rev F Jan-2020).docx
Gas Fired Boiler
Page 25