Greenheck KSF (457646) - Manual (Page 8)

8
troubleshooting:
The following is a cause and correction list for common problems with the blower unit. Also see furnace section and
the furnace manual for troubleshooting the furnace section of the unit.
symptom possible Cause Corrective action
Blower fails to
operate
Blown fuse or open circuit
breaker Replace fuse or reset circuit breaker and check
amps
Broken fan belt Replace
Defective motor or capacitor Replace
Motor starter overloaded Reset starter and check amps
Motor overamps
CFMs too high Check CFMs and adjust drives if needed
Static pressures are higher or
lower than design If higher, ductwork should be improved
If lower, fan RPMs should be lower
Blower rotation is incorrect Check rotation and correct
Motor voltage incorrect Check motor nameplate and supplied voltage
Motor horsepower too low
See specifications and catalog for fan curves to
determine if horsepower is sufficient
Shorted winding in motor Replace motor.
Insufficient airflow
Unit damper not fully open Adjust damper linkage or replace damper motor
System static pressure too high
Improve ductwork to eliminate losses using good
duct practices
Blower speed too low
Check for correct drives and RPMs with catalog
data
Dampers or registers closed Open and adjust
Dirty or clogged filters Clean or replace
Leaks in ductwork Repair
Elbows or other obstructions
may restrict fan outlet
Correct or improve ductwork
Belt slippage Adjust belt tension
Too much airflow
Blower fan speed too high Check for correct fan RPM
Filter(s) not in place. Install filters
Insufficient static pressure (SP)
(airflow resistance)
Induce SP into system ductwork.
Excessive noise
or vibration
Wheel rubbing on housing Center wheel
Loose wheel on shaft Tighten wheel setscrew
Loose motor or blower sheave Tighten sheave setscrew
Belts too loose Adjust belt tension after 24 hours of operation
Belts too tight
Loosen to maintain 3/8 in. deflection per ft. of span
between sheaves
Worn belt Replace
Motor base or blower loose Tighten mounting bolts
Worn bearings Replace
Bearing and drive alignment Realign
Motor out of balance Replace
Wheel out of balance Replace or rebalance
Sheaves eccentric or out of
balance
Replace or rebalance
Accumulation of material on
wheel
Clean wheel and housing