7.
Each heater has a wiring diagram affixed to the inside of
the access door. Consult this diagram before making
any field connections.
8.
Single or three-phase power connections may be
used
with heater models MUH0521, MUH0581,
MUH072, MUH078, MUH102, MUH108, and MUH158.
These units are factory wired for single-phase operation. If
these heaters are for use with three-phased power,
reconnect the wires as indicated in the wiring diagram
attached to the heater. Additional information can be
found by looking at the wiring illustrations in Figures 3a and
3b and following the directions shown below.
On models MUH0521,MUH0581, MUH072, MUH078, MUH102,
and MUH108 (Figure 3a), move only the two wires marked “A1”
and marked “B1”; do not move or change any other wiring. The
element lead wire marked “B1” which is factory connected to the
power terminal block (terminal located closest to the elements)
must be moved to terminal “B” on the three-phase terminal
block.
The relay (contactor) lead wire “A1” must be moved from
the end terminal of the power terminal block (terminal clos-
est to the contactor or control terminal board) to the “A” termi-
nal of the lower terminal block (center terminal).
Model MUH158 (Figure 3b) has two three-phase terminal
blocks located adjacent to the relays (contactors). Move only
the two wires marked “C1” and “D1” on each of these two three-
phase terminal blocks to terminal “B”. Do not move or change
any other wires.
9.
Electrical Accessories, either kits or factory-installed
options, are shown connected by a dash line on the
heater wiring diagram.
10.
208/240 VOLT HEATER.
Interchange transformer red
and black primary leads (see wiring diagram) when the
heater is to be connected to 208 volts supply.
A
B
LEAD WIRE
"B1"
ELEMENTS
CONTACTOR
(OR P2)
POWER TERMINAL BLOCK
HEATER FRONT
LEAD WIRE
"A1"
3 PHASE BLOCK
TO ELEMENTS
A
B
LEAD WIRE
"B1"
ELEMENTS
CONTACTOR
(OR P2)
POWER TERMINAL BLOCK
HEATER FRONT
LEAD WIRE
"A1"
3 PHASE BLOCK
TO ELEMENTS
FACTORY-WIRED FOR SINGLE-PHASE POWER
FIELD-WIRED FOR THREE-PHASE POWER
Figure 3a. Wiring Connections for Single-Phase and Three -Phase Power(MUH0521, MUH0581, MUH072, MUH078, MUH102 and MUH108)
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