10
T
EMPORARY
H
EATING
O
R
C
OOLING
If the unit is to be used for temporary heating or cooling, a “Startup,
Adjustments, and Checks” must first be performed in accordance
with this manual. Failure to comply with this requirement will void
the warranty. After the machines are used for temporary heating
or cooling, inspect the coils, fans, and motors for unacceptable
levels of construction dust and dirt and install new filters.
C
ONTRACTOR
R
ESPONSIBILITY
The installing contractor must be certain that:
•
All supply and return air ductwork is in place, properly
sealed and corresponds with installation instructions.
•
All thermostats are mounted and wired in accordance
with installation instructions.
•
All electric power, all gas, hot water or steam line
connections, and the condensate drain installation have
been made to each unit on the job. These main supply
lines must be functional and capable of operating all units
simultaneously.
•
All filters are in place.
R
OOF
C
URB
I
NSTALLATION
C
HECK
Inspect the roof curb for correct installation. The unit and curb
assembly should be level. Inspect the flashing of the roof mount-
ing curb to the roof, especially at the corners, for good workman-
ship. Also check for leaks around gaskets. Note any deficiencies in
a separate report and forward to the contractor.
O
BSTRUCTIONS
, F
AN
C
LEARANCE
AND
W
IRING
Remove any extraneous construction and shipping materials that
may be found during this procedure. Rotate all fans manually to
check for proper clearances and that they rotate freely. Check for
bolts and screws that may have jarred loose during shipment to
the job site. Retighten if necessary. Re-tighten all electrical con-
nections.
F
IELD
D
UCT
C
ONNECTIONS
Verify that all duct connections are tight and that there is no air
bypass between supply and return.
F
ILTER
S
ECTION
C
HECK
Remove filter section access panels and check that filters are prop-
erly installed. Note airflow arrows on filter frames.
P
RE
-
STARTUP
P
RECAUTIONS
It is important to your safety that the unit has been properly
grounded during installation. Check ground lug connection in main
control box for tightness prior to closing circuit breaker or discon-
nect switch. Verify that supply voltage on line side of disconnect
agrees with voltage on unit identification plate and is within the
utilization voltage range as indicated in Appendix C Electrical Data.
System Voltage - That nominal voltage value assigned to a circuit
or system for the purpose of designating its voltage class.
Nameplate Voltage - That voltage assigned to a piece of equip-
ment for the purpose of designating its voltage class and for the
purpose of defining the minimum and maximum voltage at which
the equipment will operate.
Utilization Voltage - The voltage of the line terminals of the equip-
ment at which the equipment must give fully satisfactory perfor-
mance. Once it is established that supply voltage will be main-
tained within the utilization range under all system conditions,
check and calculate if an unbalanced condition exists between
phases. Calculate percent voltage unbalance as follows:
Three Phase Models Only
3) PERCENT VOLTAGE
UNBALANCE
2) MAXIMUM VOLTAGE DEVIATIONS
FROM AVERAGE VOLTAGE
1) AVERAGE VOLTAGE
HOW TO USE THE FORMULA:
EXAMPLE: With voltage of 220, 216, and 213
1) Average Voltage = 220+216+213=649 / 3 = 216
2) Maximum Voltage Deviations from Average Voltage = 220 - 216 = 4
3) Percent Voltage Unbalance = 100 x
=
= 1.8%
Percent voltage unbalance MUST NOT exceed 2%
.
4
216
400
216
= 100 X
AIRFLOW ADJUSTMENTS
NOTE: For 2 Speed Models, airflow adjustments must be made on
high speed, i.e., 2nd stage cooling or in heat mode.
The drive on the supply fan is typically set in the middle of the
RPM range. The drive motor sheave pitch diameter is field adjust-
able for the required airflow. Refer to the following “Drive
Adjustments” section.
When the final adjustments are complete, the current draw of the
motor should be checked and compared to the full load current
rating of the motor. The amperage must not exceed the service
factor stamped on the motor nameplate. The total airflow must
not be less than that required for operation of the electric heaters
or the furnace.
If an economizer is installed, check the unit operating balance with
the economizer at full outside air and at minimum outside air. Upon
completion of the air flow balancing, we recommend replacing
the variable pitched motor sheave with a properly-sized fixed
sheave. A matching fixed sheave will provide longer belt and bear-
ing life and vibration free operation. Initially, it is best to have a
variable pitched motor sheave for the purpose of airflow balanc-
ing, but once the balance has been achieved, fixed sheaves main-
tain alignment and minimize vibration more effectively. For direct
drive units, move green wire for fan.
NOTE: On “non-two speed models” (two-speed models have a “V”
in the eleventh character of the model number), never run CFM
below 300 CFM per ton. Evaporator freezing or poor unit perfor-
mance is possible.
S
ET
E
VAPORATOR
F
AN
RPM
Actual RPM’s must be set and verified with a tachometer or strobe
light. Refer to Appendices A and B for basic unit fan RPM. Refer
also to “Airflow” section of this manual. With disconnect switch
open, disconnect thermostat wires from terminals Y and W. This
