Troubleshooting guide – VIAIR 250C-IG User Manual
Page 7

TROUBLESHOOTING GUIDE:
Tank pressure drops when 
compressor (s) shut off
1. Loose drain cock
2. Check valve leaking
3. Loose connections
1. Tighten drain cock
2. Replace check valve or
compressor(s)
3. Check all connections with
 soap and water solution 
 and tighten
Compressor runs 
continuously and air flow 
lower than normal
1. Excessive air usage
2. Loose connections
3. Worn piston ring or inlet
valve.
4. Clogged air filter element
1. Decrease air usage
2. Check all connections with
 soap and water solution 
 and tighten.
3. Repair or replace compressor
4. Replace air filter element 
Compressor runs 
continuously causing 
safety valve (if equipped) 
to open
1. Bad pressure switch
2. Defective safety valve
1. Replace pressure switch
2. Replace safety valve
Excessive moisture 
in discharge
1. Excessive water in air tank
2. High humidity
1. Drain tank, tilt tank to drain.
Drain tank more frequently
2. Move compressor to area
 with less humidity, or use air 
 line filter.
Compressor will not run
1. No power, or power switch
in OFF position
2. Blown fuse
3. Motor overheats
4. Faulty pressure switch. 
1. Make sure compressor
switch is ON
2. Disconnect compressors
 from power source, replace 
 fuse. (Refer to Specifications 
 section for correct fuse 
 amperage.)
3. Let compressors cool off for
 about 30 Minutes to allow 
 thermal overload switch reset.
4. Replace pressure switch
Thermal overload 
protector cuts 
out repeatedly
1. Lack of proper ventilation or
ambient temperature too high
2. Compressor valves failed
1. Move compressor to well
 ventilated area, or area with 
 lower ambient temperature
2. Repair or replace compressor
Excessive knocking 
or rattling
1. Loose mounting bolts
2. Worn bearing on eccentric or
motor shaft
3. Cylinder or piston ring is worn
1. Tighten mounting bolts
2. Repair or replace compressor
3. Repair or replace compressor 
CAUTION: NEVER DISASSEMBLE COMPRESSOR WHILE
COMPRESSOR IS PRESSURIZED.
USER MANUAL
250C-IG COMPRESSOR KIT
