Carrier Aero 39MN Series Installation, Start-Up And Service Instructions Manual page 239

SYMPTOM
The humidifier is too large.
There is a high limit controller fault.
Condensate in unit
Evaporation distance is too short.
Steam valve is leaking.
The trap height is incorrect.
Valve sizing is incorrect.
Steam leaks from P-traps
There is excessively high steam pressure.
AHU — Air-Handling Unit
SYMPTOM
Motor fails to start
Motor stalls
Excessive vibration
Bearing(s) hot
Motor does not run at
full speed
Motor overheats
Excessive motor noise
Motor runs and then slows
Excessive motor bearing wear
Loose Fan Belt
Drive Noise
Table 50 — Humidifier Troubleshooting (cont)
POSSIBLE CAUSES
Table 51 — Unit Troubleshooting
POSSIBLE CAUSES
Power line open
Improper wiring or loose connections
Overload trip
Mechanical failure
Improper current supply
Open phase
Overloaded motor
Low line voltage
Bearing/shaft misalignment
Shipping blocks/spacers not removed
Excessive belt tension
Drive misaligned
Grease not evenly distributed after lubrication
Over-lubrication
No lubricant
Misaligned bearing
Low voltage at motor terminals
Supply wiring to motor too small
Overloaded motor
Motor fan is clogged, preventing motor cooling
Mounting bolts loose
Rigid coupling connectors
Worn motor bearings
Fan rubbing on housing
Partial supply voltage loss
High load due to over-tensioned drive
Excessive overhung load caused by a small
diameter motor sheave
Improper motor position
Worn sheaves
Worn or damaged belt
Sheave(s) not tight on fan/motor shaft(s)
Belts contacting guard(s)
Belts too loose or too tight
Belts and sheaves mismatched
Belts not length matched (multiple belt set-up)
Misaligned sheaves
Belts worn
Belts dirty or oily
POSSIBLE REMEDIES
Verify humidifier capacity versus air volume.
Verify that high limit controller is working. If necessary, correct prob-
lem.
Verify and, if necessary, correct evaporation distance to obstructions
or elbows.
Verify steam valve is not leaking. If necessary, correct leaking steam
valve.
Ensure that height of trap exceeds the static pressure of the duct/AHU,
especially if under negative pressure.
Check valve sizing to maximum manifold capacity. If necessary, resize
valve within manifold capacity.
Check that inlet steam pressure does not exceed humidifier capability.
Reset circuit breaker.
Check wiring and connections.
Check and reset overload.
Inspect motor and drive for operation and/or damage.
Check rating plate against actual supply voltage. Contact
power provider for adjustments if needed.
Check line for open phase.
Reduce motor load or replace with larger motor.
Check supply line, correct voltage.
Check and align bearing set screws.
Remove shipping blocks/spacers.
Adjust belt tension.
Align drive.
Allow unit to cool down and restart.
Clean and purge excess grease.
Check bearings for damage and apply lubricant.
Check shaft level and reset alignment.
Check supply voltage and correct voltage loss.
Rewire with properly sized wire.
Reduce motor load or replace with larger motor.
Clean motor fan.
Tighten bolts.
Replace with flexible connectors.
Replace bearings and seals.
Adjust housing.
Check for loose/dirty connections.
Verify supply voltage.
Check belt tension and load.
Replace with larger sheave.
Adjust tension.
Replace sheaves.
Check sheave alignment and replace belt(s).
Tighten sheaves.
Adjust or tighten belt guard mounts.
Adjust belt tension.
Install proper belts.
Install matched belts.
Align sheaves.
Replace belts.
Replace belts.
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POSSIBLE REMEDIES