LAARS Mighty Therm2 MT2V (Sizes 500–2000 MBTU/h) - Install and Operating Manual - Manual (Page 21)

Mighty Therm 2
Page 21
5.1.1 Changing Single Circuit to Two
Circuits
Sizes 500 to 1500 will be shipped from the factory
for a single 120-volt power supply. To use a separate
circuit for the pump:
1. Ensure power is disabled to the unit.
2. Remove the three jumper wires that connect the
L2, N2 and GROUND wires on terminal block 1
to the main distribution terminal block. These
wires will be black/white, white and green
respectively.
5.2 Field Wiring
Main Power: The main field wiring connection
points are located inside the line voltage connection/
WARNING
The appliance must be electrically grounded in
accordance with the requirements of the authority having
jurisdiction or, in the absence of such requirements, with
the latest edition of the National Electrical Code, ANSI/
NFPA 70, in the U.S. and with latest edition of CSA
C22.1 Canadian Electrical Code, Part 1, in Canada. Do
not rely on the gas or water piping to ground the metal
parts of the boiler. Plastic pipe or dielectric unions may
isolate the boiler electrically. Service and maintenance
personnel, who work on or around the boiler, may be
standing on wet floors and could be electrocuted by an
ungrounded boiler.
Single pole switches, including those of safety
controls and protective devices must not be wired in a
grounded line.
All electrical connections are made in the field
wiring terminal strip, which is located at the right side of
the appliance.
NOTE: All internal electrical components have been pre-
wired. No attempt should be made to connect electrical
wires to any other location except the wiring box.
5.1 Main Power
All Mighty Therm2 non-pump-mounted heaters
require a single 120-volt fused supply. See Figure 15 for
over current protection ratings.
Pump-mounted Mighty Therm2 models 500 to
1500 use a single 120-volt fused supply. The installer
can change these units to use a separate circuit for the
pump, if desired. Instructions to make this change are
found in Section 5.1.1.
Pump-mounted Mighty Therm2 models 1750
and 2000 require two 120-volt fused supplies. See Figure
15 for over current protection ratings.
Figure 16. Mighty Therm2 (500–750) Wiring Diagram. Figure 15. Field Wiring.
SINGLE CIRCUIT CONN. PUMP PUMP
SIZE HEATER ONLY ONLY
W/O PUMP W / PUMP TACO B&G
500 15 20 15 15
750 15 20 15 15
1000 20 (TACO) 25 / 30 (B&G) 15 15
1250 25 30 15 15
1500 25 30 15 15
1750 25 — 15 20
2000 25 — 20 20