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Danfoss T-420 Crimp machine operator´s manual December 2022
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Troubleshooting procedures
T-421U and T-421U-110 Electric pump
Troubleshooting T-421U and T-421U-110 electric pump
IMPORTANT: Pressure must be relieved from system before disconnecting
hose, installing gauge or removing valves from pump.
Check fuse, loose wire connections, switch malfunctions or damaged cord. Pump electric cord must be
plugged into a grounded 220 volt, 60 cycle, single phase outlet on a 15 amp fused electrical circuit. If using
T-421U-110, pump electric cord must be plugged into a grounded 110 volt, 60 cycle, single phase outlet on a
30 amp fused electrical circuit.
Check oil level - after assembly and system has been purged of air the fluid level should be 1/2”from top of
reservoir. Clean, anti-wear type, hydraulic oil having a (ISO 32) 300 SSU/100 F is recommended. Use only if
operating temperature is above 0°F or below 160°F. Oil is needed to:
1) Transmit power easily through system
2) Lubricate moving parts
3) Provide seal clearances between parts
4) To cool or dissipate heat
Clean or Reset Relief Valve - A 6000 PSI pressure gauge, a 5/16” Allen wrench, a 1” socket and a screwdriver are
required. Remove cap from relief valve. Remove adjustment screw, spring and ball. Ball should be attached
to spring. Check ball and seat for possible scoring. Replace spring and ball in cavity. Insert a small punch
through spring against ball. Give punch a moderate tap to seat ball. Return adjustment screw to original
position making sure adjustment screw is at least one turn from bottoming. Remove 3/8” NPTF plug from
port above check valve and install 6000 PSI pressure gauge. With 6000 PSI pressure gauge in place operate
unit to full crimping position. Gauge should read 4000-4200 PSI. To raise setting, turn screw in (clockwise);
to lower turn screw out (counterclockwise) in 1/4 turn increments. After each adjustment recycle and read
gauge for proper setting. Run a cycle of the crimping system for final gauge reading before removing gauge
and reinstalling pipe plug.
Shuttle Valve - If the shuttle valve is in a closed position and pusher will not retract it may be helpful to tap
the shuttle valve cap several times to dislodge any silt that may be causing stem to bind. If this does not free
valve and allow pusher to retract use extreme caution prior to proceeding with shuttle valve removal as the
system is still under pressure. It may be advisable to relieve pressure at a hose connection to avoid an oil
bath. After pressure is removed from system, remove cap and valve cartridge. Soak cartridge in a PETROLEUM
BASED SOLVENT ONLY (clean Stoddard solvent). Do not use Triethene, Gasoline or Paint Thinner as they will
damage the 0-Ring Seals. If cartridge disassembly is required, use care in removing stem as it has a .0005
metal seal fit. Rotate stem in solvent and push from seat end to remove from cartridge. Do not lose the
loose ball. Wash parts in clean solvent and examine for any surface markings. If necessary, polish with a fine
crocus cloth. After final cleaning reassemble cartridge. Shake cartridge and check for free movement of ball
and stem. Replace cartridge if not functional at this point. Reassemble shuttle valve into its cavity and check
crimping cycle prior to using system.
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Summary of Contents for T-420
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