14
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
Check Valve
A check valve is s imilar to a relief valve but has a lighter spring allowing the fluid
to pass through it with little pressure loss. The purpose for this relief valve in the
hydraulic circuits covered in this guide is to prevent the fluid from back flowing to the
pump.
Com mon Problems with Check Valves
x Debris stuck on valve seat
x Torn or extruded O - rings
x Silting t Debris buildup in valve causing poppet not to move freely
15
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
Normally Closed 2 - Way
A Normally Closed 2 - Way is nothing more than a solenoid operated check valve.
When the Solenoid (coil) is activated the pilot pin retracts allowing the pressure to
equalize on either side of the poppet then the poppet will retract.
Common Problems with Normally Closed 2 - Way
x Debris stuck on valve seat
x Torn O - rings on nose
x S ilting t Debris buildup in valve causing poppet not to move freely
x Bent Stem on valve (Stem is the portion of the valve the coil slides over)
16
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
Directional Control Valve
Directional Control Valves simply tell the hydraulic fluid where to go. By
a cti vating the Solenoid (coil) the spool will shift changing the flow path.
The tolerances between the spool & the cage are tight & overtime these
tolerances can increase causing the valve to have excessive leakage. You might notice
this if over time, the cyc o š]u � ZÀ v ]vŒ �]vP ÁZ Œ À všµooÇ Ç}µ Á}v[š
able to lift a load.
17
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
Most common reasons for the directional control valve is not functioning
x Electromagnetic coil not activating
x Over torqued valve (18ft - lbs. Max )
x Torn or extruded O - ri ngs
x Debris stuck in valve
x Rust inside valve preventing spool from shifting
x Bent Stem on valve (Stem is the portion of the valve the coil slides over)
Below is the most common directional valve used 4 - way 2 position criss - cross
Ways to Check Directional Control Valve
x Valve not shifting
a. Ensure valve is not bent (stem is the section of valve the coil slides over)
b. Remove valve from manifold
c. Use dipstick on breather to push in section 1 on nose of valve. This will
manually shift the valve.
d. /( Ç}µ v[š �Z]( t the valve check for debris & or replace
Trick: By removing the white wire from the start solenoid you can place the coil back on the valve
& shift the valve after it has been removed from the manifold.
The valve should shift just as fast as you press t he button if you see the valve hesitate to
shift clean valve & try again. If problem persists replace valve
x Valve stuck in activated position
a. After removing valve c heck spool to see if it is covering the bottom half of
the crossed drilled holes in sectio n 2 of valve
b. In the valves spring offset position valve should cover the bottom half of the
crossed drilled holes on section 2 & 4
18
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
Load Holding Valve
The load holding valve checks both rod & bore end of cylinder, this valve is
different than any other load holding valve. The solenoid (coil) operated portion allows
you to retract the cylinder without having to add an orifice to restrict the f lo w of fluid
down like you would with a dual pilot operated check valve.
Common Issues with Load Hold ing Valve
x Debris in check valves
x Bent Stem on valve (Stem is the portion of the valve the coil slides over)
x Air in system not allowing pilot operated check valve to open
19
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
Trouble Shooting Quick Reference Guide
Possible Cause
Not Building Pressure Motor Not Running Cylinder Won't Extend Cylinder Won't Retract Won't Hold Load Excessive Heat From Unit Aeration of Hydraulic Fluid Reservoir Overflows Cylinder Extends With Unit Not Operating Struggles to Lift Load Load Bounces When Cylinder Retracts Start Solenoid Just Clicks-Motor Not Engaging Won't Lift Load (DC Motor Under Load) Won't Lift Load (DC Motor Not Under Load) Won't Lower Start Solenoid Stays On Cylinder won't Retract Motor Under Load
Low Battery Voltage O O O O O O O
Poor Ground Condition O O O O O O O
Check Hand Control O O O
Debris in Load Holding Valve O
Thermal Pressure Lock O O
Coil Not Energizing O O O O O
Bad Seals in Cylinder
O O O
Loose Inlet O O O O O
Packing on Cylinder Rod Worn Out O O O O O O
Hoses Connected Backwards O
Pump Not Priming O O
Clogged Orifice
O O O
Rust In Motor
O
Bad Diode
O O
Check For Additional Valving On or
Connected to Cylinder
O
Directional Valve Not Shifting Properly
O O O O O
Bad Start Solenoid
O O O
Dirty Contacts in Hand Control
O O O O
Quick Refer ence Guide covers the most common problems.
(if we have missed a step please let us know)
20
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
Symptoms & Solutions
x Not Building Pressure t
a. Gear pump not priming
D/A Remove relief valve operate pump for a few seconds until fluid comes
out of port repla ce relief valve.
S/A Same as double acting but remove check valve
b. Loose inlet on gear pump
c. Bad O - rings on relief valve or directional valve
x Motor Not Running -
a. Check Power to Start Solenoid
b. Check for Power to DC Motor
c. Check for Rust in DC Motor if a. & b . checked out ok
x Cylinder Won't Extend t
a. Check Voltage @ Start Solenoid when trying to run Power Unit
(Voltage May be below 9.5 volts )
b. Check to see if power unit is bypassing over the relief valve
c. Improper fluid in reservoir (viscosity to high)
d. Check Direc tional Valve Section D/A
e. Check Packing on Cylinder Section
x Cylinder Won't Retract t
a. Check to see if coil on load holding valve is activating
b. Check Directional Control Valve D/A
c. Pilot operated check valve not opening D/A
d. Low voltage or poor ground D/A
x Exc essive Heat From Unit t
a. Low Battery
b. Poor ground
x Reservoir Overflows t
a. Low Battery D/A
b. Poor Ground D/A
c. Air in hydraulic system
d. To small of reservoir
x Struggles to Lift Load t
a. Low battery
b. Poor ground
c. Gear pump sucking air
d. Directional valve half shifting D/ A
e. Debris in relief valve
21
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
x Start Solenoid Just Clicks - Motor Not Engaging t
a. Carbon buildup on c ontacts in start solenoid
b. Rust inside motor
c. Loose wire from start solenoid to DC motor
d. Cracked housing on start solenoid
x Won't Lift Load (DC Motor Not Under Load )
a. Low fluid level
b. Loose inlet on gear pump (air being introduced into hydraulic System)
c. Gear pump not priming
D/A Remove relief valve operate pump for a few seconds until fluid comes
out of port replace relief valve.
S/A Same as double acting but remo ve check valve
d. Worn out packing on cylinder
x Start Solenoid Stays On
a. Low battery or poor ground caused start solenoid to weld on (replace
start solenoid & check Battery & ground)
x Cylinder won't Retract Motor Under Load D/A only
a. Low Battery
b. Poor Ground
c. Coil on load holding valve not energizing
d. Directional control valve not returning to spring offset position
e. Bad packing in cylinder
Note: D/A notes solutions are for double acting hydraulic circuit
22
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
For warranty information or warranty reque st please contact Customer Service.
Power units without model number & serial number will not be covered under
warranty, when calling please have model number and serial number of the power unit.
Buyers Return Goods Authorization (RGA) Procedures
Warran ty
The following requirements must be met by Buyer to return goods for warranty
inspection.
1) Warranty request must be made via written / e - mail / call by Buyer to KTI
Hydraulics, Inc. with following information:
a. KTI Hydraulics Model Number / P/N.
b. KTI Hydrau lics Serial Number.
c. Quantities of unit/s under question.
d. Reason for return t defect, warranty or repair.
e. Suspected reasons for failure.
f. Any other Information such as Buyers PO#, KTI Invoice #, or Date of
Purchase.
Note: Any symptoms that can be provided b y buyer or operator to help find
cause of failure will help speed up the Evaluation / Return of unit.
2) KTI Hydraulics, Inc will issue a RGA number and fax a RGA form with this number
to the Buyer. All corresponding paper work will reference this RGA number .
3) Buyer must write RGA # provided by KTI on Box, and ship back per KTI
Instructions.
4) KTI will handle RGA as Specified in the RGA procedure agreement form.
5) Any units returned without a KTI assigned RGA# will be refused upon delivery
*Please Contact KTI Hy draulics Service Department For All Product Issues & Returns*
23
2621 South Daimler St.
Santa Ana, CA. 92705
Tel. 949.752 .8818 x Fax 949 .756. 1520
w w w . k t i h y d r a u l i c s i n c . c o m
Warranty Replacement / Evaluation Request Customer Name: ________________________
Request / Fax Date: _____ / ______ / _______ RGA#: _____________________
KTI Model Numb er: ___ _________________________________ Qty: _______
Original Invoice #:_____________________
Original KTI Serial Number: _________ - ________ - _________
(Units without Serial numbers will not be considered for warranty )
Return Shipping Instruction s :
To: Attn :
E - mail Address: @ .com
Address:
City / State / Zip:
Telephone #: Fax #:
Reason for Return :
(Units without Serial numbers will not be considered for warranty )
Type of Return:
RGA: ____________
RMA: ____________
C redit: ___________