Unbalanced 3-Phase Supply Voltage; Thermostat Connections; Blower Speed - Nordyne P6SD Series User's Manual & Installation Instructions

C22.1Electrical Code.Usethe grounding lugprovided
inthecontrol b oxforgrounding t heunit.
Unbalanced
3-Phase Supply Voltage
Voltage unbalance occurs when the voltages of all phases
of a 3-phase power supply are no longer equal. This
unbalance reduces motor efficiency and performance.
Some underlying causes of voltage unbalance may
include: Lack of symmetry in transmission lines, large
single-phase loads, and unbalanced or overloaded
transformers. A motor should never be operated when a
phase imbalance in supply is greater than 2%.
Perform the following steps to determine the percentage
of voltage imbalance:
.
Measure the line
voltages of your 3 phase
power supply where it
enters the building and
at a location that will
only be dedicated to the
unit installation (at the
units circuit protection
or disconnect).
Example:
A B C
(_ AB = 451V
BC = 460V
AC = 453V
2. Determine the average voltage in the power supply.
In this example, the measured line voltages were
451,460, and 453. The average would be 454 volts
(451 + 460 + 453 = 1,364 / 3 = 454).
3. Determine the maximum deviation:
Example:
From the values given in step 1, the BC voltage
(460V) is the greatest difference in value from
the average:
460 - 454 =[-6-] _ Highest
V alue
454 - 451 = 3
454 - 453 = 1
.
Determine percent of
voltage imbalance by
using the results from
steps 2 & 3 in the
following equation.
Example:
6
1O0 x _ = 1.32%
454
% Voltage Imbalance = 100 x
max voltage deviation
from average voltage
average voltage
The amount of phase imbalance (1.32%) is satisfactory
since the amount is lower than the maximum allowable
2%. Please contact your local electric utility company if
your voltage imbalance is more than 2%.
COPPER WIRE SIZE -- AWG
(1% Voltage Drop)
Supply Wire Length-Feet Supply Circuit
200 150 100 50 Ampacity
6 8 10 14 15
4 6 8 12 20
4 6 8 10 25
4 4 6 10 30
3 4 6 8 35
3 4 6 8 40
2 3 4 6 45
2 3 4 6 50
2 3 4 6 55
1 2 3 4 60
Wire Size based on N.E.C. for 60 ° type copper conductors.
Table 2. Copper Wire Size
Thermostat Connections
Several thermostat options are available depending on the
accessories installed with the unit. See Figure 10 (page
15) for 208/230V units or Figure 11 (page 16) for 460V
units. Select a thermostat that operates in conjunction with
the installed accessories. The low voltage wires must be
properly connected tothe units Iowvoltage terminal block.
Recommended wire gauge and wire lengths for typical
thermostat connections are listed in Table 3.
IMPORTANT NOTE: The thermostat should be
mounted about 5 feet above the floor on an inside
wall. DO NOT install the thermostat on an outside
wall or any other location where its operation may
be adversely affected by radiant heat from fireplaces,
sunlight, or lighting fixtures, and convective heat from
warm air registers or electrical appliances. Refer to
the thermostat manufacturer's instruction sheet for
detailed mounting and installation information.
Thermostat
Wire Gauge
24
22
2O
18
Recom mended T=Stat Wire
Length (Unit to T-Stat)
2-Wire
(Heating)
55
90
140
225
5-Wire
(Heating/Cooling)
25
45
70
110
Table 3. Thermostat Wire Gauge
Blower Speed
CAUTION:
To avoid personal injury or property damage,
make certain that the motor leads cannot
come into contact with any uninsulated metal
components of the unit.
10