Lead Lag Instructions - NY Thermal Trinity Lx-WH Series Installation And Operation Manual

│Installation and Operation Manual
Trinity Lx-WH

11.0 LEAD LAG INSTRUCTIONS

Multiple Water Heater Applications
The Lx controller has the internal capacity to stage or Lead-Lag up to 8 water heaters configured in a cascade.
This Lead-Lag capability allows a designated "Master" water heater to communicate with and effectively control
each water heater in a multiple water heater system. This function is accomplished by "Daisy Chaining" a 3-
wire cable between each of the water heaters and enabling the Master parameter in the water heater of your
choice. The water heater with the Master parameter enabled becomes the single point of contact for settings and
control wiring. Use the instructions detailed in this section to set-up and install the cascade water heater system;
reference Appendix A – Controller and Touchscreen Display Instructions for details on more advanced settings
and for assistance with navigating the touchscreen display.
Lead Lag Instructions
Plumbing – install as many as 8 Lx water heaters in a parallel plumbing configuration as illustrated in Figure 11-
1. Size common piping as per Table 11-1.
Water Heater Pump – each water heater must have its own circulator (see Figure 11-1) which is controlled by its
PUMP B output; see Field Wiring Figures and Tables 12-1(a) and 12-1(b). The water heater pump must be
sized according to Table 10-5.
Communication Wiring – using 3-wire cable, daisy-chain terminals LL DATA +, LL DATA – and SENSOR
COM of each water heater in parallel; see Field Wiring Tables 12-2(a) and 12-2(b) and Figure 12-2.
System Sensor – a system sensor is NOT used in a water heater application, at the Master boiler set the
applicable sensor input to Unconfigured as follows:
Configure – Sensor Configuration – S10 (J10-7) sensor [S5 (J8-11) sensor for Lx500WH-Lx800WH
models] – UNCONFIGURED
Modbus Address – assign a unique MB2 Modbus Address to each water heater in the cascade. Access the MB2
Modbus Address setting via the System Identification & Access menu as follows:
Configure – System Identification & Access – MB2 Modbus Address
Master Enable – choose one (and only one) water heater in the cascade to be the Master, this water heater will
receive all control wiring and will be used for setting control parameters (see steps below). On this one water
heater, set Master enable equal to Enabled via the Lead Lag Master Configuration menu, accessed as follows:
Configure – Lead Lag Master Configuration – Master enable
Tank Thermostat – connect to SENSOR COM and DHW of the Master water heater; see Field Wiring Tables 12-
2(a) and 12-2(b) and Figure 12-2. Switch must be an isolated end switch (dry contact).
DHW Setpoint – at the Master water heater only, set the DHW setpoint via the Lead Lag Master Configuration
menu, accessed as follows:
Configure – Lead Lag Master Configuration – DHW setpoint
DHW switch (Lead Lag) – at the Master water heater only, set DHW switch equal to DHW (S6) sensor shorted
via the Lead Lag Master Configuration menu, accessed as follows:
Configure – Lead Lag Master Configuration – Advanced Settings – Domestic Hot Water – DHW switch
DHW enable (Local) – at the Master water heater only, set DHW enable equal to Disabled via the Domestic Hot
Water Configuration menu, accessed as follows:
Configure – Domestic Hot Water Configuration – DHW enable
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Lx – WH Series