INGERSOLL-RAND
AIR COMPRESSORS
CENTAC
Troubleshooting Guide
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
Copyright Notice
Copyright 1996-1997 Ingersoll-Rand Company
THE CONTENTS OF THIS MANUAL ARE PROVIDED “AS IS” AND WITHOUT ANY IMPLIED
WARRANTIES WHATSOEVER.
Ingersoll-Rand air compressors are not designed, intended, or approved for breathing air
applications. Ingersoll-Rand does not approve specialized equipment for breathing air
applications and assumes no responsibility or liability for compressors used for breathing air
service.
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
Table of Contents
Surge______________________________________________________________________1
Low Seal Air Pressure________________________________________________________2
Low System Air Pressure _____________________________________________________3
High Vibration ______________________________________________________________4
Low Control Air Pressure _____________________________________________________5
Low Instrument Air Pressure __________________________________________________5
Failure to Start ______________________________________________________________6
No Control Power ___________________________________________________________7
Failure to Load______________________________________________________________7
Low Oil Pressure ____________________________________________________________8
High Oil Temperature ________________________________________________________9
High Air Temperature _______________________________________________________10
Common Conversions and Information ________________________________________11
1. Temperature __________________________________________________________11
2. Pressure – gauge______________________________________________________11
2. Pressure – gauge, continued ____________________________________________12
3. Length_______________________________________________________________12
4. Flow_________________________________________________________________13
5. Volume ______________________________________________________________13
6. Electrical_____________________________________________________________14
6. Electrical, continued ___________________________________________________15
7. Vibration _____________________________________________________________16
8. Water Quality Requirements_____________________________________________17
CENTAC TROUBLESHOOTING GUIDE
1
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
Surge
Cause Solution
1. Dirty inlet air filter. Replace filter.
2. Too small inlet pipe (remote-mounted
air filter).
Replace pipe.
3. High interstage air temperatures. Investigate. Check to see what is
necessary to lower air temperatures.
Check water temperature, water flow,
water pressure, etc.
4. Increase in water temperature. Investigate. Check to see if it is possible
to lower water temperature.
5. Increase in inlet air temperature. Lower setpoint.
6. Setpoint higher than design discharge
pressure of compressor.
Lower setpoint.
7. Defective system pressure controller. Adjust or replace.
8. Too low CLL or LLR (throttle surge). Increase CLL or LLR setting.
9. Too low P1, PR3, or mechanical stop
adjustment (unloaded surge).
Increase P1, PR3 or adjust mechanical
stop.
10. Improper calibration of valve I/P,
positioner, or actuator.
Calibrate as necessary.
11. Defective bypass valve. Repair or replace.
12. Restriction in customer's system. Investigate. Take necessary steps to
correct restriction. Check for closed block
valve or excessive dryer pressure drop.
13. Restricted air flow through air coolers. Clean air coolers.
14. Dirt build-up on impeller vanes. Clean impeller.
15. Blockage of diffuser air passage. Clean diffuser.
16. Improper wheel clearance. Reset clearance.
17. Worn or damaged impeller. Replace.
18. Butterfly valve pin broken. Replace pin.
19. Discharge check valve hanging up. Repair or replace.
2
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
Low Seal Air Pressure
Cause Solution
1. Seal air regulator malfunctioning. Adjust, clean, or replace regulator.
2. Low instrument air pressure. Increase instrument air pressure.
3. Damaged seal air line. Replace.
4. Leaking fitting. Replace or tighten.
5. Leaking seals. Replace.
6. Seal air bleed valve open too far. Adjust.
7. Instrument air filter dirty. Clean or replace element.
8. Excessive clearance between pinion
and seal.
Investigate. Replace seal and/or pinion.
CENTAC TROUBLESHOOTING GUIDE
3
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
Low System Air Pressure
Cause Solution
1. Incorrect setpoint. Adjust.
2. Incorrect valve calibration. Restroke valves.
3. Bad controller. Repair or replace.
4. Dirty inlet filter. Replace filter elements.
5. Compressor operating unloaded. Switch selector switch to load.
6. System demand greater than
compressor capacity.
Check for excessive air usage like open
valves, leaking fittings, etc., and correct.
Start additional compressor. Recommend
that customer purchase another Centac if
additional capacity is required.
7. Compressor block valve closed. Open valve.
8. Incorrect controls calibration. Adjust controls.
9. Discharge check valve sticking. Repair or replace.
10. System air pressure sensing point in
wrong location.
Relocate control air connection
11. Excessive pressure differential across
air dryer.
Investigate and correct.
12. Too low CLH setting. Increase setting (Do not exceed
FLA+SF).
13. Leaking bypass valve. Investigate and correct. Replace seat;
free up sticking valve.
14. Bypass valve stays open; inlet valve
functions normally.
Lower CLL to activate bypass valve on
MP3 panel. Ensure 2TR is operating
properly on Electro-Pneumatic panel.
4
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
High Vibration
Cause Solution
1. Low oil temperature. Increase oil temperature by adjusting oil
heater thermostat. Close cooling water
valves to oil cooler. Circulate oil.
2. High oil pressure. Reduce pressure. Adjust main oil pump
pressure relief valve with oil at operating
temperature.
3. Oil not draining properly from
bearings.
Investigate and correct. Check for
restriction, improper venting, too high oil
level.
4. Incorrect coupling alignment. Realign coupling.
5. Worn coupling. Replace.
6. Excessive grease in coupling. Remove excessive grease.
7. Bad bullgear or intermediate gear
bearings.
Replace.
8. Unbalanced motor rotor. Have motor rotor balanced.
9. Bad motor bearings. Replace.
10. Worn rotor assembly parts. Replace rotor assembly or necessary
parts.
11. Excessive build-up on impellers. Clean and balance rotor assembly.
12. Excessive pipe strain. Remove pipe strain.
13. Incorrect type of oil. Replace with correct oil.
14. Bad rotor assembly bearings or seals. Replace.
15. Excessive moisture carryover. Investigate and correct. Check for
restriction in condensate drainage
system.
16. Inadequate oil supply to plain
bearing.
Investigate and correct. Ensure oil supply
groove in plain bearing shell is aligned
properly with oil supply hole through
casing.
CENTAC TROUBLESHOOTING GUIDE
5
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
Low Control Air Pressure
Cause Solution
1. Too small control air line. Replace with larger diameter pipe.
2. Moisture in control air line. Remove moisture.
Provide permanent method for moisture
removal.
3. Sensing control air pressure from
wrong location.
Change location of sensing pressure.
4. Leaking fittings or damaged pipe. Repair or replace.
5. Closed C.A. valve. Open valve.
Low Instrument Air Pressure
Cause Solution
1. Instrument air line too small. Replace with a larger pipe.
2. Instrument air dryer malfunctioning. Repair or replace.
3. Instrument air valve closed. Open valve.
4. Instrument air supply pressure below
recommended pressure.
Increase supply pressure. Obtain a
different air source of adequate pressure.
5. Dirty I.A. filter. Clean or replace.
6. I.A. filter wrong size. Replace.
7. Leaking fittings or damaged pipe. Repair or replace.
6
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
Failure to Start
Cause Solution
1. No power to motor starter. Energize power.
2. Blown fuse. Replace blown fuse.
3. STOP button pushed in. Pull out STOP button.
4. Overloads tripped. Reset overloads.
(If trip occurs do not reset find cause of
trip)
5. Control wiring incorrect. Investigate and correct.
6. Trips at transition. Mechanical linkage out of adjustment.
Bad 2M contactor. Replace or repair
contactor.
7. Interlocks not satisfied. Investigate and correct. Adjust
mechanical interlocks.
8. Bad motor starter. Repair or replace.
9. Loose or corroded wiring. Tighten and/or clean as necessary.
10. Control relay defective. Replace.
11. Low voltage. Investigate. Increase voltage supply.
Increase wire size. Increase breaker size.
12. Control circuit not grounded properly. Ground neutral at transformer. Check
wiring.
13. Wiring to remote starter incorrect. Investigate and correct.
CENTAC TROUBLESHOOTING GUIDE
7
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
No Control Power
Cause Solution
1. POWER ON selector switch OFF. Turn POWER ON switch to ON.
2. Blown fuse. Replace fuse.
3. Bad control power transformer. Replace.
4. Control power transformer wired
incorrectly.
Correct transformer wiring.
Failure to Load
Cause Solution
1. LOAD selector switch in the wrong
position.
Turn switch to LOAD.
2. Inlet valve stuck. Investigate and correct.
3. Controller setpoint too low. Adjust.
4. No control air signal. Investigate and correct. Check for closed
valve.
5. Surge sensor tripped. Adjust or replace.
6. Bypass valve will not close. Investigate and correct.
7. No power air to inlet or bypass valve. Investigate. Open power air shutoff valve.
8. Valve actuator or positioner
malfunctioning.
Repair or replace.
9. REMOTE/LOCAL switch for CEM in
wrong position.
Turn to REMOTE for CEM operation.
10. Incorrect CLL setting. Reset to correct value.
8
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
Low Oil Pressure
Cause Solution
1. Incorrect relief valve adjustment. Adjust main oil relief valve to obtain 25-27
psi at correct operating oil temperature.
2. Dirty oil filter. Replace.
3. Leaking check valve. Replace.
4. Defective main oil pump. Repair or replace.
5. Leaking bullgear cover seal. Remove cover and install new silicone
sealant around oil supply groove.
6. Leaking or pinched suction line. Repair or replace.
7. Low oil level. Ensure 1-1/2" - 2" oil cover (minimum)
above top of suction screens.
8. Excessive gerotor axial clearance. Tighten axial clearance.
9. Wrong prelube pump motor. Obtain correct prelube pump motor.
10. Wrong size pump. Install correct pump.
11. Too big prime line. Install smaller prime line or remove
entirely.
12. Suction and discharge lines reversed. Correct.
13. Unloaded oil pressure low. Increase P1 value.
CENTAC TROUBLESHOOTING GUIDE
9
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
High Oil Temperature
Cause Solution
1. Inadequate water flow. Provide adequate water flow to the oil
cooler.
2. High water temperature. Lower water temperature; use a cooler
water source.
3. Bad AMOT valve. Replace.
4. Water control valve thermostat out of
calibration.
Calibrate controller.
5. Dirty oil cooler on water side. Clean water side of oil cooler.
6. Incorrect oil. Check oil specification against I-R oil
requirements; install correct oil.
7. Water/glycol mixture greater than
50/50.
Adjust mixture to ensure the glycol is not
greater than 50%.
8. Water temperature supply higher than
oil cooler design.
Install larger oil cooler or additional
cooler.
9. Heat exchanger radiating fins dirty. Clean fins.
10. Incorrect number of water passes. Investigate. Orient return bonnett
correctly; replace bonnett gasket if
bypassing; install cooler with more
passes.
10
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
High Air Temperature
Cause Solution
1. Inadequate water flow. Provide adequate water flow to the air
cooler; adjust water flow to the air cooler.
2. High water temperature. Lower water temperature; use a cooler
water source.
3. Water control valve thermostat out of
calibration.
Calibrate controller.
4. Plugged water passages or scale on
the tubes.
Clean water side of air cooler.
5. Water flow bypassing air cooler. Investigate and correct. Replace waffle
gasket if it is missing or damaged. Reglue
it if it is loose.
If shroud is loose, reinstall with correct
pop rivets. Never use aluminum pop
rivets.
6. Water/glycol mixture greater than
50/50.
Adjust mixture to ensure the glycol is not
greater than 50%.
7. Heat exchanger radiating fins dirty. Clean fins.
8. Water flows backward. Cold water
inlet on cooler hot air inlet side is
backwards flow.
Investigate. Repipe if water piping is
backwards; switch backflush valve to
correct position.
9. Air cooler oriented incorrectly. Remove air cooler and rotate to align the
water ports correctly with the water
connections of the casing.
CENTAC TROUBLESHOOTING GUIDE
11
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
Common Conversions and Information
1. Temperature
Fahrenheit to Celsius °C = 5/9 (°F-32°)
Celsius to Fahrenheit °F = 9/5°C + 32°
2. Pressure – gauge
PSI to Atmosphere PSI X 0.06805
PSI to inches of H
2
O at 68°F PSI X 27.73
PSI to inches of mercury (in Hg) at 0°C PSI X 2.036
PSI to kPa PSI X 6.8948
PSI to Kg/cm
2
PSI X 0.07031
Kg/cm
2
to Atmosphere Kg/cm
2
X 0.9678
Kg/cm
2
to bars Kg/cm
2
X 0.98066
Kg/cm
2
to inches of mercury (in Hg) at 0°C Kg/cm
2
X 28.96
Kg/cm
2
to kPa Kg/cm
2
X 98.066
Kg/cm
2
to PSI Kg/cm
2
X 14.223
kPa to PSI kPa X 0.145
bars to PSI bars X 14.504
inches of H
2
O at 68°F to inches of mercury (in Hg) at 0°C in H
2
O X 0.07342
inches of water at 68°F to psi in H
2
O X 0.03606
inches of water at 68°F to kPa in H
2
O X 0.2487
inches of water at 68°F to Kg/ cm
2
in H
2
O X 0.002535
inches of water at 68°F to bar in H
2
O X 0.002487
inches of water at 68°F to standard atmosphere (atm) in H
2
O X 0.002454
inches of mercury at 0°C to inches of water at 68°F in Hg X 13.62
inches of mercury at 0°C to psi in Hg X 0.03606
inches of mercury at 0°C to kPa in Hg X 3.3864
12
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
2. Pressure – gauge, continued
inches of mercury at 0°C to Kg/cm
2
in Hg X 0.034532
inches of mercury at 0°C to bar in Hg X 0.033864
inches of mercury at 0°C to standard atmospheres (atm) in Hg X 0.03342
atmosphere (standard) to bar atm X 1.01325
atmosphere (standard) to psi atm X 14.696
atmosphere (standard) to Kg/cm
2
atm X 1.0332
atmosphere (standard) to Kg/m
2
atm X 10332
atmosphere (standard) to kPa atm X 101.325
3. Length
inches to meters (m) in. X 0.0254
inches to centimeters (cm) in. X 2.54
inches to millimeters (mm) in. X 25.4
meters to inches (in.) m X 39.37
centimeters to inches (in.) cm X 0.3937
millimeters to inches (in.) mm X 0.03937
mills (0.001") to millimeters 0.001" X 0.0254
CENTAC TROUBLESHOOTING GUIDE
13
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
4. Flow
cubic feet per minute (scfm) to cubic meters per second (nm
3
/s)
scfm X 0.0004719
cubic feet per minute (scfm) to cubic meters per hour (nm
3
/h)
scfm X 1.699
cubic feet per minute (scfm) to cubic centimeters per second
(cm
3
/s)
scfm X 471.9
cubic feet per minute (scfm) to cubic meters per minute (nm
3
/m)
scfm X 0.02832
1000 scfm = 28.32 nm
3
/m
cubic meters per hour (nm
3
/h) to cubic meters per minute (scfm) nm
3
/h X 0.016667
cubic meters per hour (nm
3
/h) to cubic meters per second (nm
3
/s) nm
3
/h X
0.00027778
cubic meters per minute (nm
3
/m) to cubic feet per minute (scfm) nm
3
/m X 35.315
gallons per minute (US) to cubic meters per minute (nm
3
/
m)
gpm X 0.0037854
gallons per minute (US) to cubic meters per hour (nm
3
/h)
gpm X 0.2271
gallons per minute (US) to cubic feet per hour (scfh) gpm X 8.021
gallons per minute (US) to liters per second (L/s) gpm X 0.06309
5. Volume
gallons (US) to cubic inches (in
3
)
gal. X 231
gallons (US) to cubic meters (m
3
)
gal. X 0.0037854
gallons (US) to liters (L) gal. X 3.7854
liters (L) to cubic inches (in
3
)
L X 61.024
liters (L) to cubic meters (m
3
)
L X 0.001
liters (L) to gallons (US) L X 0.26418
cubic inches (in
3
) to cubic meters (m
3
) in
3
X (16.387 X 10
-
6
)
cubic meters (m
3
) to cubic inches (in
3
) m
3
X 61024
cubic meters (m
3
) to cubic ft. (ft
3
) m
3
X 35.315
cubic feet (ft
3
) to cubic meters (m
3
) ft
3
X 0.02832
14
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
6. Electrical
Amps (I) = current
Ohm (R) = resistance
Watts (W) = electric power
Kilowatts (KW) = electric power
Kilovolt - amps (kVA) = apparent electric power
Kilowatt hour (KW/hr) = unit of electric energy or work performed
Joule (J) = metric unit of energy in watt per sec.
Volt (E) = unit of electric pressure or electromotive force
eff = efficiency (expressed as a decimal)
pf = power factor (expressed as a decimal)
hp = horsepower output
AC = alternating current
Ohms Law Relationship (direct current - DC)
E
I
R
=
×
E
W
I
=
E
WR
=
W
I
R
=
2
W
E
R
=
2
W
E
I
=
×
I
E
R
= I
W
E
=
I
W
R
=
R
E
I
= R
W
I
=
2
R
E
W
=
2
kva
IE
=
1000
single phase AC( ) kva
IE
=
1
73
1000
.
(3-phase AC)
KW
IE
=
1000
(DC) KW
IE
pf
=
(
)
(
1000
single phase AC)
KW
IE
pf
=
1
73
1000
.
(
)
(3-phase AC)
Power Factor
(pf)
=
kva
kw
CENTAC TROUBLESHOOTING GUIDE
15
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
6. Electrical, continued
hp
IE
eff
=
(
)
746
(DC)
hp
IE
eff
pf
=
(
)
(
)
746
(single phase AC)
hp
IE
eff
pf
=
1
73
746
.
(
)
(
)
(3-phase AC)
J
IE
=
sec
(DC)
J
IE
eff
pf
=
(
)
(
)
sec
(single phase AC)
J
IE
eff
pf
=
1
73
.
(
)
(
)
sec
(3- phase AC)
Amps(hp known) (DC)=
746
(
)
( )
hp
E eff
Amps (hp known) (single phase AC)=
746
(
)
( )( )
hp
E eff pf
Amps(hp known) (3-phase AC)=
746
1 73
(
)
. ( )( )
hp
E eff pf
Amps(KW known) (DC)=
1000
KW
E
Amps(KW known) (single phase AC)=
1000
KW
E pf( )
Amps(KW known) (3-phase AC)=
1000
1 73
KW
E pf. ( )
Amps(kva known) (single phase AC)=
1000
kva
E
Amps(kva known) (3- phase AC)=
1000
1
73
kva
E
.
16
CENTAC TROUBLESHOOTING GUIDE
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-Dec-94
7. Vibration
A = Acceleration in g's (in/sec
2
) = Peak
V = Velocity in in/sec = Peak
D = Displacement in mils = Peak - Peak
f = Frequency in Hz
V
A
f
= ×61 34.
V
f
D
=
×
×
0
0031416
.
D
V
f
= ×318 3. D
A
f
= ×19 570
2
,
A D f= × ×0 0000511
2
.
A
V
f
=
×
×
0
0162
.
RMS (root mean square) = 0.707 X
Peak
RMS = 1.111 X average RMS = 0.354 X Pk - Pk
average = 0.637 X Peak
average = 0.900 X RMS
2
average = 0.318 X Pk - Pk
Pk - Pk (Peak to Peak) = 2 X Peak Pk - Pk = 2.828 X RMS Pk - Pk = 3.142 X average
Pk (Peak) = 1.414 X RMS Pk = 1.571 X average
CENTAC TROUBLESHOOTING GUIDE
17
CST-TP0007
1994 Ingersoll-Rand Company
Date of issue: January, 1999 Supersedes: 16-dec-94
in
mm
/
sec.
/
sec.
.
=
×
0
03937
mm
in
/
sec.
/
sec.
.
=
×
25
40
total vibration(in mils) =1 25
12000
. ×
RPM
8. Water Quality Requirements
Total hardness (expressed as CaCo
3
) less than 100 PPM
Suspended solids less than 50 PPM
Maximum water temperature (cooler discharge) 140°F/60°C
pH range 6.0 - 8.5
Langlier saturation index (LI) +0.5 - +1.0
A low pH level promotes corrosion and high levels of dissolved oxygen.
A high pH level increases the chance of scale formation.
A low LI indicates the water tends to be corrosive.
A high LI indicates a tendency to form scale.
It is recommended to contact a reputable water treatment professional if there are questions
regarding water quality.
Rev. C
24 Mar. 1995
AVERAGE RMS
PEAK TO PEAK
PEAK
0
+
-
0.707
0.637
/