14
Fan Powered Terminal Units IOM
GENERAL
Before balancing the system, the air handlers must be
operating in accordance with the specifications for air
capacity, static pressure, and temperature. Record data on a
unit performance sheet (Figure 9). The following items must
be checked:
1.
All fans must be running at calculated and specified rpm.
2.
Permanent or temporary filters must be clean and in-
stalled where required.
3.
All central station dampers must be adjusted and
operating properly.
4. All thermostats must be calibrated and at the desired
settings.
5.
All ductwork must be tight.
6. All dirt or loose lining must be removed from inside
ductwork.
7.
Pumps and sprays, when used, must be in operation.
INLET DIAMETER
INLET AREA
CFM @ 1 IN. WG
4”
0.087 ft
2
230
5”
0.136 ft
2
360
6”
0.196 ft
2
515
8”
0.349 ft
2
920
10”
0.545 ft
2
1430
12”
0.785 ft
2
2060
14”
1.069 ft
2
2800
16”
1.396 ft
2
3660
TABLE 7 – Inlet Areas
START-UP
SYSTEM CALIBRATION OF THE INLET AIRFLOW SENSOR
To achieve efficient pressure independent operation, the
velocity sensor and averaging flow probe must be calibrated
to the controller. This will ensure that airflow will be accurate
for all terminals at system start-up.
System calibration is accomplished by calculating a flow
coefficient that adjusts the pressure fpm characteristics.
The flow coefficient is determined by dividing the flow for a
given unit (design air volume in cfm), at a different velocity
pressure of 1.0 in. wg, by the standard pitot tube coefficient
of 4005. This ratio is the same for all sizes, if the standard
averaging probe is used.
Determine the design air velocity by dividing the design air
volume (the flow at 1.0-in. wg) by the nominal inlet area (sq.
ft). This factor is the K factor.
Krueger inlet areas are shown in the table. The design air
volume is shown in this table. It can be determined from
Table 7 that the average design air velocity for units is equal
to 2660 fpm at 1.0-in. wg.
8. Connections to the coil, when used, must be checked.
9.
Water control valve, if used, must be checked.
NOTE: All KQF* & QF* Series terminal units are shipped
with cardboard packaging rings placed in one side of
the blower housing internal to the blower/motor. These
rings are provided to prevent damage to the motor
during shipment. The rings MUST BE REMOVED prior to
operation. The packing rings are accessible through the
terminal’s plenum. Turn the fan wheel by hand to insure
that blower is free spinning. Krueger will not accept
responsibility for any additional costs for removal of
this packaging material.
IMPORTANT: Before proceeding with start-up, be
certain that voltage, frequency, and phase correspond
to unit specifications. Unless noted, all fan motors are
60 Hz, 115, 208/240, or 277 v, single-phase ac. electric
heat, the electric heat voltage may exceed the blower
motor voltage requirement. Excessive voltage to the
fan box may seriously damage it. Verify that the DDC (if
equipped) are receiving 24-v ac, –15%, +20%
INITIAL START-UP PROCEDURES
NOTE: The following steps MUST be followed in order to
properly operate and service this unit.
1. Disconnect all electrical power to the unit. Failure to
disconnect the power to the fan box prior to checking
and/or servicing the fan box could result in a serious
injury.
2. Verify that the fan box is installed level, and that adequate
mounting support has been provided.
3.
Remove motor access panel from the bottom of the fan
box, and also remove the control panel cover.
4.
Test the fan motor setscrew. The setscrew should fit
tightly, but it may have come loose during shipment or
installation.
5.
Rotate the blower by hand to ensure proper clearance
between the blower and the blower housing.
6.
Check the fan box for loose fiberglass insulation,
especially on the electric heater elements or the hot
water coils (if these accessories are installed).
7.
Check the control enclosure and remove any debris.
8.
Check the induced air inlet filter (if provided) for
obstructions, and verify the filter is securely in place.
9.
Verify the main power supply to the connection to the
fan box for proper voltage. If the fan box is installed with
electric heat, the electric heat voltage may exceed the
blower motor voltage requirement. Excessive voltage to
the fan box may seriously damage it. Verify that the DDC
(if equipped) are receiving 24v-ac, –15%, +20%.Identify
the control system supplied.
10. Check all control connections (and/or electric) for proper
installation.
11. Connect electrical power.
Summary of Contents for KLPP
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