Download PACKAGED ROOFTOP ARRANGEMENTS

PROBLEM
PROBABLE CAUSE
SOLUTION
2. CFM Low
Insufficient Air Flow
Filters
Dirty or clogged.
Coil - DX or Chilled Water
Dirty or clogged.
Obstructions in High Velocity Air Stream
a. Obstruction near unit outlet.
b. Sharp elbows near unit outlet.
c. Improperly designed turning vanes.
d. Projections, dampers or other obstructions in part
of duct system where air velocity is high.
3. CFM High Too Much Air Flow
System
a. Oversized duct work.
b. Access door open.
c. Registers or grilles not installed.
d. Filters not in place.
e. System resistance lower than anticipated.
4. Blower Does Not Operate
Blower
Blower RPM is too great.
Installation
a. Incorrect electrical connection.
b. Wrong voltage.
c. Blown fuse.
Unit
a. Broken belt(s).
b. Loose pulleys.
c. Power to unit is disconnected.
d. Motor overload protector has broken circuit.
e. Optional thermostats, firestats, freezestats may
lockout blower operation if set incorrect.
TROUBLESHOOTING GUIDE – ELECTRIC MOTORS
PROBLEM
PROBABLE CAUSE
SOLUTION
1. Motor
Blown fuse or open circuit breaker.
Replace fuse or reset circuit breaker.
Overload trip.
Check and reset, if manual.
Improper line connections.
Check connections to unit wiring diagram.
Improper current supply.
Check to determine that power supply agrees with
motor nameplate specifications.
Mechanical failure.
Check bearings.
Determine that motor and drive turn freely.
Motor overloaded.
Reduce load or replace motor.
With a 3 phase power source, one
phase may be open.
Check line for open phase.
Defective capacitor.
Replace capacitor.
Wrong application.
Consult manufacturer.
Overloaded motor.
Reduce load or replace motor.
Low line voltage.
Check across AC line and correct
if possible.
2. Motor Stalls
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