Reznor R6GN Unit Installation Manual - Manual (Page 15)

15
Example :
AB = 451V
BC = 460V
AC = 453V
2. Determine the average voltage in the power supply.
3. Determine the maximum deviation:
4. Determine percent of voltage
imbalance by using the results
from steps 2 & 3 in the following
equation.
max voltage deviation
from average voltage
= 100 x
average voltage
% Voltage Imbalance
6
454
100 x = 1.32%
Example:
1. 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).
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:
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).
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%.
Example:
From the values given in step 1, the BC voltage (460V)
is the greatest difference in value from the average:
460 - 454 = 6
454 - 451 = 3
454 - 453 = 1 Highest Value
• A two-stage heating/cooling thermostat is required
for R6GN series units. Select a thermostat which
operates in conjunction with the installed accessories.
The thermostat should be mounted about 5 feet above
the floor on an inside wall. See Figure 10 for proper
wire gauge and their recommended lengths for typical
thermostat connections.
• The low voltage wires must be properly connected
to the units low voltage terminal block. Route 24V
control wires through the gas furnace side of the unit.
Recommended wire gauge and wire lengths for typical
thermostat connections are shown in Figure 10.
• 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 information.
Thermostat / Low Voltage Connections
• Single Package Gas Heating / Electric Cooling Rooftop
Units are designed to operate with a 24 VAC Class II
control circuit. The control circuit wiring must comply
with the current provisions of the NEC (ANSI/NFPA
70) and with applicable local codes having jurisdiction.
Thermostat connections should be made in accordance
with the instructions supplied with the thermostat and
the indoor equipment.
Figure 10. Typical 2 - Stage Heat/Cool
Thermostat Connection
Y1
Y2
W2
W1
G
RH
RC
Y1
Y2
W2
W1
G
R
Indoor
Thermostat
Sub-Base
Unit Low Voltage
Terminal
t-Stat Wire
Gauge
Recommended T-Stat Wire
Length - Ft. (Unit to T-Stat)
18 Ga. 0 - 60
16 Ga. 61 - 130
Field Supplied Wiring - - - - - Use Solid Class II Copper Wire
Blower Speed
The blower speed is preset at the factory but must
be verified at each installation. For optimum system
performance and comfort, it may be necessary to change
the factory set speed. Refer to the Blower Performance
Data (Tables 5 & 6, pages 26 & 27) for proper operating
range. Always inspect variable pitch sheaves for proper
tightness and set screws
cautIoN:
To avoid personal injury or property damage,
make sure the motor leads do not make contact
with any uninsulated metal components of the
unit.