Specifications

Part number 550-100-090/0809
g a s -f i r e d w a t e r b o i l e r — Boiler Manual
26
Make the following connections, some of which depend on
your system and how the U-Control will be programmed.
Connect 120VAC power (minimum 15-amp

source)
Connect wiring for up to three circulators
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Connect thermostats and/or heat demand con-

tacts
The U-Control can regulate the boiler for up to three •
different heating systems.
Install system & outdoor sensors, when used
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The boiler is shipped with an outdoor sensor, a •
system supply sensor and a system return sensor.
The system supply sensor will be required for most
space heating applications. The system return sensor
must also be installed when using the system supply
sensor. Use of the outdoor sensor is optional.
Locate the sensors on the system piping as shown •
in Figure 4, page 11 and other piping drawings
throughout this manual.
Line voltage power input
Provide and install a fused disconnect or service switch 1.
(15-ampere rated recommended) as required by ap-
plicable codes.
Connect minimum 15-ampere, 120 VAC power wiring 2.
to Ultra boiler line voltage terminal strip as shown in
Figure 32, page 27, and Figure 98, page 80.
Wiring circulators
The U-Control provides for connection of up to three 1.
circulators, one of which must be the boiler circulator.
In addition, you can connect a system circulator and a
DHW circulator, for examples.
The maximum allowable current for each
circulator is 2.2 amps at 120 VAC
. For
circulators with higher amp ratings, you must
install a circulator relay or starter to provide
line voltage to the circulator. For circulators
rated over 2.2 amps, connect only the circula-
tor relay or starter coil to the Ultra circulator
terminals.
Wiring — general
The U-Control provides plug-in, color-coded, non-interchangeable 1.
terminal strips for all field wiring. See the schematic diagram (Fig-
ure 98, page 80) & ladder diagram (Figure 99, page 81).
The U-Control provides programmable flexibility in system op-2.
eration, allowing control of heat supply for up to three different
heating systems. Read this manual thoroughly before connecting
the wiring to ensure trouble-free start-up and operation.
Wiring — overview
See this and following pages for wiring information. Also see the
Advanced section of this manual for addtional wiring connections
and options
.
Field wiring — basic system
ELECTRICAL SHOCK HAZARD — For your
safety, turn off electrical power supply at service
entrance panel before making any electrical con-
nections to avoid possible electric shock hazard.
Failure to do so can cause severe personal injury
or death.
Wiring must be N.E.C. Class 1. If original wir-
ing as supplied with boiler must be replaced, use
only type 105 °C wire or equivalent. Boiler must
be electrically grounded as required by National
Electrical Code ANSI/NFPA 70 – latest edition.
Installation must comply with:
1. National Electrical Code and any other national, state, provincial
or local codes or regulations.
2. In Canada, CSA C22.1 Canadian Electrical Code Part 1, and any
local codes.
See page 78 (Advanced section) for other wiring options