KRUEGER A Series User Manual

39
KHF - SERIES A FAN COIL UNITS
INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
TROUBLESHOOTING (CONTINUED)
EC MOTOR (CONTINUED)
PROBLEM POSSIBLE CAUSE CORRECTIVE ACTION
POOR AIRFLOW
PERFORMANCE
[EC MOTOR]
Lack of required external static pressure External static pressure not as designed. Adjust external static pressure to design pressure.
[24V units] Three speed switch in wrong position Verify three speed switch, if present, is set to desired speed.
Poor voltage quality Verify input voltage within acceptable parameters.
Speed adjustment outside fan operating range
Refer to Fan Calibration curve on unit. Adjust speed on PWM Controller to value that will allow motor to start.
See instructions for Adjusting EC Motor Speed.
Erratic speed command (in Proportional Control mode) Verify 2-10V analog signal at Remote Control input terminals.
Improper duct connections Verify ductwork is installed per SMACNA and ASHRAE guidelines.
Duct obstruction Verify no obstructions. Verify all dampers are full open while fan operates.
Improperly set dampers Verify proper inlet air to unit.
Dirty coil Check cleanliness of coil. Dirty coil ns will restrict airow.
Dirty lters Check for dirty or blocked lters. Replace as needed.
Damaged or blocked blower Verify blower rotates freely. Clear blockage.
FAN MOTOR STARTS
BUT STOPS.
[EC MOTOR]
Voltage or ground loss at motor Verify proper voltage and ground at motor.
Blower blocked Clear blockage. Verify blower rotates freely with motor disconnected.
Loss of fan speed command.
Verify operation of thermostat or controller. Verify fan speed command at relay board.
Refer to Fan Relay Board Troubleshooting Guide.
Motor overloaded
Use amp meter to verify motor amps. Disconnect power from unit. Verify motor rotates freely by hand with
blower disconnected. If not, replace motor. Note: EC motors may not rotate freely as the rotor aligns with the
stator magnets.
Open ductwork Verify ducts sealed properly.
Motor overheated due to lack of airow
Verify dampers, if present, are not closed. Verify there are no obstructions in the discharge ductwork and/or at
the plenum opening. Verify lter is not dirty and does not obstruct airow.
Voltage or ground loss at motor Verify proper voltage and ground at motor power terminals.
PWM board error or faulted Refer to PWM board status LEDs. Verify all connections. Cycle power to the board. Refer to PWM board IOM.
Motor fault or end of life Replace motor.
FAN MOTOR STARTS
BUT STOPS.
[EC MOTOR]
Faulty motor harness
Reseat connector and verify operation.
Disconnect motor harnesses and verify continuity. Replace motor harness.
EC MOTOR SPEED
CANNOT BE ADJUSTED
PWM board error or faulted Refer to PWM board status LEDs. Verify all connections. Cycle power to the board. Refer to PWM board IOM.
Improper wiring connections Verify wiring. If Fan Relay board present, verify all jumpers installed.
EC wiring harness damaged or improperly seated
Unplug harness and re-install, making sure plugs are fully seated.
See section on checking wire harnesses, below. Replace harness if damaged.
No control signal EC motors may run at idle speed if they lose PWM signal while enabled.
Verify PWM signal at motor connector. Refer to PWM board IOM.
ESP (external static pressure) too high
Verify dampers, if present, are not closed. Verify there are no obstructions in the discharge ductwork and/or at
the plenum opening. Verify lter is not dirty and does not obstruct airow.
Motor control failure Replace motor.
EC MOTOR RUNS IN
REVERSE, DOESN’T
RESPOND TO SPEED
ADJUSTMENT
Motor control failure Replace motor.

KRUEGER A Series Specifications

General

Brand	KRUEGER
Model	A Series
Category	Fan
Language	English