P-K SOLIS™
Gas Fired Boiler
Technical Service 1.877.728.5351
Revised: March 15, 2021
Released: March 15, 2021
Patterson-Kelley 2021
All Rights Reserved.
2701000090 P-K SOLIS NURO Installation and
Owners Manual (Rev A).docx
Page 67
6.1 Terminal Block Assignments
Terminal Block Assignments — Low Voltage (TB1) Terminal Block
Terminal Number
Label
Description
27
ECOM 3
Wireless Outdoor Air Receiver
26
ECOM 2
25
ECOM 1
24
MODBUS SHIELD
2-Wire MODBUS RS485 & Shield Terminal
23
MODBUS COM B
22
MODBUS COM A
21
MODBUS/CASCADE REF
Reference Terminal (Application Dependent)
20
CASCADE B TO B
2-Wire Cascade & Shield Terminal
19
CASCADE A TO A
18
CASCADE SHIELD
17
GROUND
Ground Terminal for I/O Devices
16
ANALOG OUTPUT [-]
4-20mA Analog Output Tracks Boiler Firing Rate
100% Firing Rate = 20mA, 1% Firing Rate = 4mA
15
4-20mA ANALOG OUTPUT [+]
14
NIGHT SETBACK
Contact Closure Enables Night Setback Operation
Open Circuit Disables Night Setback Operation
13
NIGHT SETBACK
12
OUTDOOR TEMP SENSOR
Outdoor Air Temperature Sensor for ODA Reset
Configurable for 10k
Ω
or 12k
Ω
Sensor
11
OUTDOOR TEMP SENSOR
10
DHW STAT / SENSOR
DHW Enable Circuit Configurable for SPST Break-on-
rise Aquastat, or 10k
Ω
or 12k
Ω
Tank Sensor
9
DHW STAT / SENSOR
8
HDR TEMP SENSOR
Hydronic Supply Header Temperature Sensor
Configurable for 10k
Ω
or 12k
Ω
Sensor
7
HDR TEMP SENSOR
6
SPARE ANALOG INPUT
Reserved for Future Use
5
SPARE ANALOG INPUT
4
ANALOG INPUT [-]
4-20mA Analog Input
Configurable for Setpoint or Firing Rate Control
3
4-20mA ANALOG INPUT [+]
2
ENABLE / DISABLE
Contact Closure Enables Comfort Heat Operation
Open Circuit Disables Comfort Heat Operation
1
ENABLE / DISABLE