Troubleshooting guide – VIAIR 100C 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
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.	Replace	compressor
4.	Replace	air	filter	element	
Compressor	runs	
continuously causing 
safety	valve	(if	equipped)	
to open
1. Faulty 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 
 water separator
Compressor will not run
1. No power, or power switch
in OFF position
2. Blown fuse
3.	Motor	overheats
4. Faulty pressure switch 
 (if hooked up to a 
 pressure switch).
1. Make sure compressor
switch is ON
2. Disconnect compressor
 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	to	reset.
4. Replace pressure switch
Thermal	overload	
protector cuts out 
repeatedly
1. Lack of proper ventilation or
ambient temperature is too high
2. Compressor valves failed
1. Move compressor to well
	ventilated	area,	or	area	with 
 lower ambient temperature
2. 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 bolts
2.	Replace	bearing	or	
 piston assembly
3.	Replace	piston	or	compressor	
CAUTION: NEVER DISASSEMBLE COMPRESSOR WHILE
COMPRESSOR IS PRESSURIZED.
USER MANUAL
100C Air Compressor Kit
PROBLEM:
POSSIBLE CAUSE(S)
CORRECTIVE ACTION
