Heavy Duty Balanced Opposed Compressors - Ariel Corporation

For Models: JGH:E:K:T Section 2 - Instrumentation
Troubleshooting DNFT’s
NOTE: When installing multiple DNFTs, wire each to a separate alarm circuit of the control
panel, annunciator, or PLC to simplify lubrication system and DNFT troubleshooting.
Problem
LED does not
blink and
control panel
indicates lube
no-flow. (see
also Erratic
Shutdown)
Rupture disc
blows and
divider valve
seizes after
DNFT
installation.
Erratic shutdown
or LED
blink.
Possible
Cause
Improperly
adjusted
DNFT.
Broken spring
or magnet in
magnet
housing.
Low battery
voltage.
Bent magnet
housing.
Wrong magnet
housing
installed on
divider valve.
Air or
debris in
divider valve
assembly.
Faulty wiring
from DNFT to
control panel
or air in system
(see
above for air
in system).
Faulty lube
pump.
Solution
Loosen set screws, slide DNFT all the way onto hex of magnet housing and
torque to 25 inch pounds max. (Do not over tighten). Either pump clean oil
through lubrication system with a purge gun or run the compressor to cycle
the divider valve. If necessary, slide DNFT back in 1/16“ increments until LED
blinks with each divider valve cycle.
Loosen set screws, remove DNFT from magnet housing. Remove magnet
housing from divider valve. Remove magnet, spring, and spacer and check
for damage. Replace damaged components. Re-install magnet housing on
divider valve and DNFT on magnet housing. If necessary, adjust DNFT, check
for LED blink. Purge air from system with purge gun.
Remove battery from DNFT and test it. Replace battery with a factory recommended
replacement lithium battery if voltage is below 2.5 volts.
Loosen set screws, remove DNFT from magnet housing. Check for damaged
or bent magnet housing. Remove magnet assembly from divider valve.
Replace magnet housing, magnet, spring, and spacer. Re-install new magnet
housing on divider valve and DNFT on magnet housing. If necessary, adjust
DNFT, check for LED blink. Purge air from system with purge gun.
Loosen set screws and remove DNFT from magnet housing. Check for correct
magnet housing for divider valve manufacturer. Remove and replace with
correct magnet housing. Re-install DNFT on new magnet housing. If necessary
adjust DNFT, check for LED blink. Purge air from system with purge gun.
Check system pressure to verify oil flows to divider valves. If needed, install
pressure gauge to monitor lubrication system operation:
• Loosen outlet plugs in front of valve blocks. Purge lubrication system with a
purge gun until clean, clear, air-free oil flows from plugs.
• Loosen each piston enclosure plug individually to purge air from behind piston.
Do not remove piston enclosure plugs. Tighten all divider valve plugs.
Adjust DNFT.
To ensure proper lubrication system operation, all tubing and components
MUST be filled with oil and free of air before start-up.
A-10753
A-10772
• Normally Open - Attach ohmmeter to red wires. Should read 10
megaohms in operation and less than 10 ohms in alarm.
• Normally Closed - Attach ohmmeter to orange wires. Should
read less than 10 ohms in operation and infinity in alarm.
• Normally Open - Attach ohmmeter to orange wires; insulate violet
wires from each other. Should read 10 ohms or less in alarm.
A-10754
• Normally Closed - Attach ohmmeter to orange wires. Short violet
wires together. Should read infinity in alarm.
Check system pressure to verify oil flows to divider valves. If needed, install
pressure gauge to monitor lubrication system operation. Check gauge to verify
pump builds sufficient pressure to inject oil into cylinder. Do not remove
tubing from check valve and pump oil to atmosphere to check oil flow into cylinder.
Replace pump.
3/11 PAGE 2-11