Instructions / Assembly
Table Of Contents
- Part 1 - General Safety Information
 - Part 2 - Before You Start
 - Part 3 - Prepare the Boiler
- A. Locating the Boiler
 - B. Structure
 - C. Leveling
 - D. Clearances for Service Access
 - E. Wall Mounting Considerations
 - F. Wall Mounting Instructions
 - G. Residential Garage and Closet Installations
 - H. Exhaust Vent and Intake Pipe
 - I. Carbon Monoxide Detectors
 - J. Prevent Combustion Air Contamination
 - K. Removing a Boiler from a Common Vent System
 - K. Water Chemistry Requirements*
 - L. Technical Specifications
 
 - Part 4 - Piping
- A. General Plumbing Information
 - B. Relief Valve
 - C. Backflow Preventer
 - D. Potable Expansion Tank
 - E. Circulators
 - F. Hydronic Piping with Circulators, Zone Valves, and Multiple Boilers
 - G. Circulator Sizing
 - H. Check / Control Water Chemistry
 - I. Plumbing
 - J. Fill and Purge Heating System
 - K. Glycol Antifreeze Solutions
 - L. Zoning with Zone Valves
 - M. Zoning with Circulators
 - N. Multiple Boilers
 - O. Applications*
 
 - Part 5 - Venting
 - Part 6 - Condensate Removal
 - Part 7 - Wiring
- A. Installation Must Comply With
 - B. Field Wiring Terminations
 - C. Field Wiring
 - D. Line Voltage Wiring for Standard Boiler
 - E. Alarm Connections
 - F. Low Voltage Connections for Standard Boiler
 - G. Thermostat
 - H. Outdoor Sensor
 - I. Indirect Sensor
 - J. Optional 0-10 Volt Building Control Signal
 - K. Optional UL353 Low Water Cut-Off Interface Kit
 - L. Wiring of Cascade System Communication Bus
 - M. Cascade Master Pump and Sensor Wiring
 - N. Cascade Follower Pump and Sensor Wiring
 
 - Part 8 - Gas Connections
 - Part 9 - Start-Up Preparation
- A. Check / Control Water Chemistry
 - B. Check for Gas Leaks
 - C. Freeze Protection (When Used)
 - D. Fill and Test Water System
 - E. Purge Air from Water System
 - F. Check Thermostat Circuit(s)
 - G. Condensate Removal
 - H. Final Checks Before Starting Boiler
 - I. Setting Up a Single Boiler
 - J. Setting Up a Cascaded System
 - K. Lockout Condition
 - L. Cascade System Programming
 
 - Part 10 - Start-Up Procedure
 - Part 11 - Start-Up Procedures for the Installer
 - Part 12 - Troubleshooting
 - Part 13 - Maintenance
 - Part 14 - Shutdown
 - Part 15 - Installation Checklist
 - Part 16 - Maintenance Report
 - Part 17 - Replacement Parts
 

LP-387 Rev. 011 Rel. 006 Date 6.28.19
40
D. Line Voltage Wiring for Standard Boiler
NOTE: A termination plug is included in the CAT 3 / CAT 5 Bus 
Connection Point, labeled J3 in Figure 29. DO NOT REMOVE THIS 
PLUG! Doing so will aect boiler operation and void warranty.
1. Connect the incoming power wiring to the line voltage 
terminal strip in the electrical junction box at terminals 120V, 
Neutral, Ground (shown in Figure 29).
2. A line voltage fused disconnect switch may be required, 
externally mounted and connected according to local codes that 
may apply.
3. Connect the boiler pump as shown in Figure 29 to the terminals 
marked 1 – (HOT), 2 – (NEUT), and 3 – (GND). The connections 
shown are suitable for a maximum continuous pump draw of 3 
amps at 120 volts. If the pump requires more current or voltage 
than the 120 volts supplied, an external motor starter or contactor 
will be required.
4. Connect the DHW pump to the terminals marked 4 - HOT, 5 - 
NEUT, 6 - GND.
E. Alarm Connections
The control includes a dry contact alarm output. This is an SPDT 
circuit, rated at 5 amps at 120 volts. This contact can be used to 
activate an alarm light or bell or notify a building management 
system if the boiler goes into a lockout condition. The circuit 
between the ALARM COM and NC terminals is closed during 
normal operation and the circuit between ALARM COM and 
NO is open during normal operation. The connections depicted 
in Figure 29 show two 120 volt lights connected to the alarm 
terminals. One light will be on when the boiler is in normal mode 
and the other light will be on when the boiler is in lockout mode.
F. Low Voltage Connections for Standard Boiler
1. All low voltage cables should enter the electrical junction box 
through the provided knock out holes as shown in Figure 28.
2. Connect all low voltage eld devices to the low voltage 
terminal strip located in the electrical junction box.
G. Thermostat
1. Connect the room thermostat to the terminals marked 
THERMOSTAT in the electrical junction box (see Figures 29 and 32). 
Alternately, any dry contact closure across these terminals will cause 
the boiler to run. Take caution to ensure neither of the terminals 
becomes connected to ground.
2. Mount the thermostat on an inside wall as central as possible 
to the area being heated, but away from drafts or heat producing 
devices such as television sets that could inuence the ability of the 
thermostat to measure room temperature.
3. If the thermostat is equipped with an anticipator and it is 
connected directly to the boiler, the anticipator should be set at 
.1 amps. If the thermostat is connected to other device(s), the 
anticipator should be set to match the power requirements of the 
device(s). See the instruction manual of the connected device(s) for 
further information.
If the boiler is congured as a cascade master, the system pump 
output is a dry contact output capable of switching 5 amps at 
120 volts, in addition to the boiler pump output sourcing 4 amps 
each.
The electrical junction box has separate, clearly marked terminal 
strips for line voltage and low voltage wiring. Special jacks are 
provided for trouble-free cascade system wiring using standard 
CAT3 or CAT5 patch cables.
NOTE: If local electrical codes or conditions require an additional 
service switch, the installer must provide and install a fused 
disconnect or 15 amp (minimum) service switch.
BOILER CONTROL
CAT3/CAT5 CONNECTION POINTS
GND
Figure 29 - Control Wiring
H. Outdoor Sensor
There is no connection required if an outdoor sensor is not used or 
the system requires a xed operating temperature.
1. Use a minimum 22 AWG wire for runs of 100 feet or less and minimum 
18 AWG wire for runs of up to 150 feet.
2. Mount the outdoor sensor on an exterior surface of the building, 
preferably on the north side in an area that will not be aected by 
direct sunlight and will be exposed to varying weather conditions. 
NOTE: For correct mounting procedures, follow instructions provided 
with the sensor.
NOTE: If sensor wires are located in an area with sources of potential 
electromagnetic interference (EMI), the sensor wires should be 
shielded, or the wires routed in a grounded metal conduit. If using 
shielded cable, the shielding should be connected to the common 
ground of the boiler.
I. Indirect Sensor
There is no connection required if an indirect water heater is not used 
in the installation.
1. The boiler will operate an indirect red water heater with either 
a thermostat type aquastat installed in the indirect tank or an HTP 
7250P-325 tank sensor. When a tank sensor is used, the boiler control 
will automatically detect its presence and a demand for heat from the 
indirect water heater will be generated when the tank temperature 
falls below the user set point by more than the user selectable oset. 
The demand will continue until the sensor measures that the indirect 
water heater temperature is above the set point.










