Trinity Lx
│
Installation and Operation Instructions
Lx – WH Series
58
Table 12-2(b) Low Voltage Field Connections (Lx500WH-Lx800WH)
Connection
Location
Description
COM (24VAC)
1
24VAC Common
– Neutral for the 24VAC power supply within the water heater.
R1/R2 (24VAC)
2
24VAC Hot
- Power supply for inputs EXT. LIM, CH1, and CH2 (LL).
3
EXT. LIM
4
External Limit
– Input requiring 24VAC from terminals R1/R2 to permit the burner to
operate. Comes factory equipped with a jumper to the R2 terminal. For installations
requiring the use of an additional safety switch, such as a LWCO or auxiliary temperature
limit, remove the factory installed jumper and install the normally open isolated contacts
of the field supplied additional limit in place of jumper. Flow Switch factory installed and
prewired in series with EXT LIMIT jumper.
GAS LO PR.
1
5
Gas Low Pressure Switch (Optional)
– Comes factory equipped with a jumper. For
applications requiring a Low Gas Pressure Switch, remove jumper and connect normally
open isolated contacts of the Gas Low Pressure Switch. Switch must be installed external
to unit (24VAC circuit). For preapproved High Gas Pressure Switch, see Note 1 below.
6
AUX. PROOF
7
Auxiliary Proof
– Comes factory equipped with a jumper. For applications using Indoor
Combustion Air (Lx500-800 only), remove jumper and replace with field supplied end
switch incorporated with motorized damper/louver control.
8
CH1 *
9
Local Central Heat Demand
– Not applicable for Water Heater Applications.
CH2 (LL) *
10
Lead-Lag Central Heat Demand
– Not applicable for Water Heater Applications.
Sen
so
r
DHW
2
11
DHW Tank Demand
–
Input requiring closure of terminals 11 and 14 to initiate a demand
for DHW. Switch made via isolated end switch (dry contact) from the storage tank
thermostat (Aquastat). Or optional Tank Sensor (P/N 84632); see Appendix A.
OD / SYS
SENSOR *
12
Outdoor Temperature Sensor
– Not applicable for Water Heater Applications.
System Water Temperature
– Not applicable for Water Heater Applications.
TOD
13
Time of Day (Night Time Setback)
– Input requiring closure of terminals 13 and 14 to
initiate TOD setback setting. Switch is made using an isolated end switch (dry contact)
using a timer, BAS or other device.
SENSOR
COM
14
System Common
–
Common port for field inputs DHW, OD Sensor and System Sensor.
4
-20mA
(– / +)
15
External Modulation Control
– Using a 4-20mA signal, an external control can be used
to directly modulate the burner firing rate or adjust the active set point. This can be useful
for applications using external staging controls or Building Automation Systems.
16
C
o
m
m
u
n
icatio
n
s
LL DATA+
17
Lead-Lag
–
Connects internally to the controller’s MB2, Modbus communication port.
Terminals 17, 18 and 14 (common) can be "daisy-chained" to multiple water heaters (up to
8 in total) for the purpose of staging.
LL DATA-
18
BMS D+
19
Building Management System (BMS)
– Connects internally to the display’s COM2,
Modbus communication port. Terminals 19, 20 and 14 (common) can be connected to a
Gateway for communication to a BMS or other device.
BMS D-
20
ALARM
(A & B)
21
Normally Open Alarm Contacts
– Contacts close during a lockout or other alarm
condition. May be connected to a BMS, maximum capacity of 0.63Amps at 24VAC.
22
Notes
1
For applications requiring a High Gas Pressure Switch, see supplemental instructions included with NTI High Gas
Pressure Switch Kit, P/N 84094. Note: this is the only High Gas Pressure Switch that has been tested with the unit
and preapproved for field installation within the appliance cabinet.
2
Tank Sensor – when operating in a cascade system, the water heater controls do not support the use of a tank sensor; a
tank thermostat (switch) must be used.
*
Asterisk indicates connection not used or applicable for Water Heater Applications.
