Reznor RXH (Outdoor PreevA) Unit Installation Manual - Manual (Page 44)

Form I-RDH/REH/RHH/RXH (12-14), Page 44
If the power supply is not within these tolerances, contact the power company prior to
operating the system.
Check Voltage Supply - See voltage use range on the rating plate. Measure (and
record) each supply leg voltage at all line disconnect switches. Readings must fall
within the allowable range.
Check Voltage Imbalance (applies to units with optional reheat compressor) - In a
3-phase system, excessive voltage imbalance between phases will cause compres-
sor motor to overheat and eventually fail. Maximum allowable imbalance is 2%. To
determine voltage imbalance, use recorded voltage measurements taken above in the
following formula.
CAUTION: If this unit
is allowed to operate
on an electric supply
that is not within the
specified tolerances,
the product warranty
shall be void. See
Hazard Levels, page 2.
Key:
V1, V2, V3 = line voltages as measured
VA (average) =
(V1 + V2 + V3)
3
VD = line voltage (V1, V2, or V3) that deviates farthest from average (VA)
Formula: % Line Voltage Imbalance =
[100 x (VA - VD)]
VA
NOTE: These
requirements and
procedures would also
apply to compressors on
the condensing unit.
Reheat Compressor Wiring (applies to units with optional reheat compressor) - A
3-phase scroll compressor must be phased correctly or compressor will operate in
reverse. Since there is a chance of unknowingly connecting the power in such a
way as to cause compressor rotation in reverse, it is important to check this on
startup.
CAUTION: Be sure to connect pressure gauges to the suction and
discharge lines before startup so that compressor rotation can be
checked immediately. Scroll compressors will be destroyed if operated
in the wrong direction. See Hazard Levels, page 2.
Before initial startup, connect refrigerant pressure gauges to the compressor suc-
tion and discharge lines. At startup, initiate a call for reheat, and observe the gauges.
If the suction pressure rises and discharge pressure drops, the compressor is
operating in reverse and should be shut down. (After several minutes of operation
in reverse, the compressor’s internal protector will trip. If a compressor is repeatedly
allowed to restart and run in reverse, the compressor will be permanently damaged.)
Turn off the power and switch the 3-phase line voltage wiring connections before
restarting the unit.
Blower Motor Wiring - Check rotation of the blower. If rotation is not correct, three-
phase motor may be reversed by interchanging two wires on the 3-phase supply con-
nection.
Disconnect Switch - A disconnect switch is available as optional equipment or may
be supplied locally. When installing the disconnect switch, be careful that the conduit
and switch housing are clear of all service doors. Allow at least four feet (1.2M) of ser-
vice room between the disconnect switch and any service panels. When providing or
replacing fuses in a fusible disconnect switch, use dual element time delay fuses and
size 1.25 times the maximum total input amps.
DANGER
To prevent injury or death due to electrocution or contact with
moving parts, lock disconnect switch open. See Hazard Levels,
page 2.
Optional On/Off Switch, Option BA6 - The unit may be equipped with a cabinet-
mounted non-fusible, lockable, service on/off switch. The switch is conveniently
located on the control side of the unit.
Optional Phase Loss or Low/High Voltage Protection, Opt BF15 or BF14 - A
3-phase system may be equipped with an optional phase loss protection device.
Option BF15 is an auto-reset control that shuts down the unit on phase loss or phase
reversal. Option BF14 performs the same function but will also shut down the unit on
high or low voltage condition.
7.2.2 Supply Wiring
Options
WARNING (Models
RDH and RHH):
If you turn off the
power supply, turn
off the gas.
7.0 Electrical
(cont’d)
7.2 Supply Wiring
(cont’d)
7.2.1 Supply Voltage (cont’d)