Maxton UC1A - DOWN SECTION TROUBLESHOOTING

1728 Orbit Way - Minden, Nevada 89423 P: 775-782-1700 F: 775-782-1701 info@maxtonvalve.com www.maxtonvalve.com

62
\\SERVER\CATALOG2019\2019CatalogRev2

CAUTION:
 The information herein is for use by skilled hydraulic elevator professionals.
 Before disassembly of the valve, make sure the power is off by turning the main disconnect switch
off and that the elevator is resting on the buffers (zero system pressure).
DOWN SECTION
CAR WILL NOT LOWER
 Check coil voltage.
 Check line shut off valve and tank shut off valve.
 Turn DS (Down Stop) adjuster in clockwise (CW) to stop.
 Turn DA (Down Acceleration) adjuster out counterclockwise (CCW) more.
 Turn DT (Down Transition) adjuster in (CW) slowly. If car will not lower, turn ML (Manual
Lowering) screw out (CCW) all the way. If car lowers with ML screw open, first check for
proper coil voltage. If voltage is correct, then check both D and DL solenoid assemblies for
debris and / or damage. Ball Cage must operate freely within the solenoid tube.
 Replace the solenoid seat.
 Check down piston ring for damage
 Check piston guide and seat for freedom of movement.
SLOW DOWN START
 Turn DA (Down Acceleration) adjuster out (CCW).
 Turn DS (Down Stop) adjuster in (CW).
 Check jack packing and guide shoes for any binding.
 Remove D solenoid assembly. Check for debris and / or damage. Ball Cage must operate
freely within solenoid tube.
 Replace solenoid seats.
HARSH OR BOUNCY START
 Bleed air from jack.
 Check for packing or guide shoe friction.
FAST DOWN START
 Turn DA (Down Acceleration) adjuster in (CW).
CAR COMES DOWN IN LEVELING SPEED ONLY
 Check coil voltage to D (Down Valve) solenoid.
 Land car and remove D solenoid assembly. Check for debris and /or damage. Ball Cage must
operate freely within solenoid tube.
 Replace solenoid seats.
MAIN DOWN SPEED TOO SLOW
 Make sure gate valves are open between valve and jack and between valve and tank.
 Turn D (Down Speed) adjuster out (CCW).
 Install pressure gauge at “B” port. Check pressure during full down speed and compare to
flow chart. If there is any abnormal pressure drop, check for restriction in piping from valve to
jack and from valve to tank.
 Check flow capacities of pipe between valve and jack and between valve and tank.
 Replace solenoid seats.
 Check down piston for damage.
TROUBLE SHOOTING PROCEDURES UC4, UC4M, UC4MR B44