Water Box Do’s and Don’ts

Do change the water in the water box after every pour. This allows you to look for gray slurry passing pistons, evidence of worn piston heads. It also allows you to monitor for leaking drive cylinder packing’s.

Do mount the water box cover with the mount bolts for solid stability. Especially after service maintenance.

IMG_2006_1

Do inspect Dog-Bone bolts for tightness. They must be secured with stainless steel tie wire, never with normal steel bailing wire.

IMG_2032_1

Do change the water box after long pours to help cool the hydraulic system. Water box water is used for 30% of the cooling system for hydraulic oil. Oil coolers take up the remaining 70%.

Don’t ever have hands or tools inside the water box while the motor is running. This reduces the risk of serious injury.

Don’t leave water box cover loose after maintenance or during use.

Don’t add soap to the water box water. This will wash the oil film off of the drive cylinder rods and will wear out the drive cylinder chevron seals faster.

Don’t leave water in the water box overnight or over long periods of time if there is danger of freezing.

Building a Counterweight Lock

Basic requirements when building a counterweight lock:
  • Weights must be at least 6,000 kilograms, but not well over. This could lead to a “nose heavy” boom when extended over the front.
  • The weights must be off the ground.
  • The pull lock cylinder must be retracted BEFORE raising the machine with outriggers.  The cylinder must be retracted to 2″ or less ( < 50 mm ) when the cylinder circuit goes to relief.  At this time the weight will still be on the ground.  When the machine is raised, with the outriggers, the weights will come off the ground.

Dimensions of the counterweight can be a simple block but can vary in many different shapes. For example, Putzmeister provides a bracket style with the unit. Regardless of the weight’s shape, how wide, tall, and deep the weight is should be calculated according to the material used.

12107927n
12107885n

Belt(s) won’t run? I’ll bet it’s not the pump.

Belt(s) won’t run?  I’ll bet it’s not the pump.

2 of 3 – Hydraulic

This is the second of three articles about Telebelt belt-related problems.

From time to time, I get calls involving a belt that won’t run, or runs very slowly.  The call I like the least is, “My feeder (or main) belt quit running.  I replaced the pump, but it still won’t run.”

With over 800 Telebelts in the field, we are looking at more than 2,100 piston pumps.  We don’t hear of pump failures very often.

So, again, I’ll bet it’s not the pump.

Rule # 1 – Check to see if it will run with manual control.  If it will, the problem is probably electrical or in the radio.  If not, it’s mechanical or hydraulic.

Things that stop belts:

  •  Mechanical problems
  • Electrical problems
  • Hydraulic problems
  • Truck or engine failure (this is beyond the scope of this series)

 

Let’s deal with hydraulic problems.  By now you should have observed Rule #1 and you know the problem is not electrical and you cannot run manually.

 

Is there any pressure on the belt circuit, main or feeder?

If one belt is working, but one is not, connect a 400 bar gauge to the “M” test port for the belt that is not working.  This is explained in your manuals in the maintenance section.

  • Always hook up the 400 bar gauge first.  If there is over 60 bar you will blow your 60 bar gauge.
  • If neither belt is working, double check that the driver-side PTO shaft is turning.  This is just about the only thing that could cause both belt pumps to quit together.
  • If the belt works under normal load but stalls under a very heavy load, a larger displacement motor might be required.  Example: Feeders have motors that deliver optimum output under normal conditions.  Extreme loads, i.e. paving, might require larger motors with more torque.  Use a pressure gauge to see if the belt stalls at full pressure (280 bar) or if it has no pressure when it quits.

 

Is there pressure below 60 bar?

  • If it is below 60 bar, connect your 60 bar gauge.
  • Disconnect the square plug on the motor control valve for the pump you are working.  Another way would be to pull the belt card or belt card fuse for the pump you are working on.  This will insure you are not getting a false reading from belt card zero.
  • You will now be able to read standby (low) pressure.

 

Is there pressure above 60 bar?

  • Disconnect the square plug on the motor control valve for the pump you are working.  Another way would be to pull the belt card or belt card fuse for the pump you are working on.  This will insure you are not getting a false reading from belt card zero.
  • When the pressure drops below 60 bar, connect your 60 bar gauge.
  • You will now be able to read standby (low) pressure.

Location of Valves and Power Plugs

 

 

 

 

Belt Card Location

Belt Card Fuse Location

 

Is the pressure below 20 bar?

Using the prssure setting procedure in the manual, set standby to:

  • All feeder belts – 20 bar
  • Main belts except TB and TBS 130/600 – 20 bar
  • Main belts TB and TBS 130/600 – 25 bar
  • Boom/Outrigger pumps – 22 bar

 

Are the standby pressures low or erratic?

  •  This could indicate broken springs or a stuck standby spool.  Lightly tap the control valve (compensator) with a hammer – this often frees stuck spools.
  • Screw the pressure adjusting screw all the way in – this will override broken springs.
  • If these steps don’t work, shut the machine off.  Release air pressure on pressurized tank units.  Remove the low pressure spool and check for contamination or scoring.
  • If you think you have a bad compensator, swap it with the other belt pump and see if the problem changes to the other circuit.  (This can’t be done with the 140CC main belt pumps on a TB-130)

Note:  Compensator (control valve) problems are often the cause of pump “failures.”  A pump with low or no standby pressure will not come on stroke.  Repairing or replacing the compensator often does the trick.

 

If the standby pressure can be set:
Using the procedure in the manuals, check and set high pressure.  All pumps are set to 280 bar for high pressure.

  • If high pressure cannot be reached, eliminate problems that can cause this:
    • Motor leakage
    • Piston packing leaks
    • Valve spool leakage
    • Counterbalance or relief valve leakage

 

If you get this far, it might actually be the pump
The only way to truly test a pump is with a flow meter.  Even a bad pump delivers flow until back pressure is applied. You can also get a rough idea of pump condition by checking function times.

  • Time your belts to determine belt speed
  • Compare this to the times recorded on the pump test page, in the front of your manual
  • Rule of thumb; Main belts usually run 900 feet/min when delivered.  Feeders usually run 1,000 feet/minute.  If you get a low reading, check the motor(s) to make sure they haven’t been changed to a higher displacement.
  • You can also use function times to determine changes in the boom/outrigger pump.
  • A flow meter can also be used to check leakage rates from the pump case drain.

Last minute update:

 

A problem, with a customer’s TB-130, has been plaguing all involved for the last month.  They shelled the boom/outrigger circuit pump.  This was a true pump failure; what we call “grenading itself.”

After cleaning the system and installing a new pump, the circuit would work for a short time, and then the pressure would drop off.  Pushing and releasing the clutch would bring the pressure back, and then it would drop off, again.  Compensators, inlet modules, WBV valves and a second pump were tried, without any change.  The customer even took parts off a working TB-110 and the problem remained.  Three of us, at Putzmeister, with over 100 years of combined experience were convinced it was a problem in the boom control valves.

In desperation, Alan went back to the schematic.  Something we had not considered jumped out at him; the contingency pump circuit.  This is the small electric motor and pump that allow the boom to be raised, so the cab can be tipped, if the engine won’t start.  It feeds the boom circuit through a check valve.  The check valve poppet had hammered itself out of shape and it was allowing circuit flow back through the small pump.

This reinforces: 1) the value of the schematic, 2) the K.I.S.S. theory and 3) the “I’ll bet it’s not the pump” statement.

Update on Telebelt Belt Circuit Adjustments

SETTING PRESSURES ON TELEBELT BELT CIRCUITS.

The main conveyors and feed conveyors of Telebelts are two separate hydraulic circuits.  Each has their own pumps, control valves and motors and they are hydraulically independent of each other.

The hydraulic pump capacities vary.  Different models have different pump sizes, depending on belt length.  In addition, Telebelts that have direct drive pumps (TBS) and automatic transmissions use pumps that have capacities that differ from manual transmission Mack counterparts.

This is about pressure setting, not capacity.  Capacity (flow) determines belt speed.  Pressure is the resistance to flow.  If the pressures are correct, the pumps should deliver the required flow.  Pressures are checked with pressure gauges, supplied with the machines when new.  Flow is measured with a flow meter, which is not supplied.

Again, flow determines speed.  A “working man’s” flow meter is a stopwatch.  Data sheets, provided with the machines show function speeds when the unit was in final test.  For example, a test sheet might show 65 seconds to slew the main boom 360 degrees to the right.  If you obtain the same results, with pressures properly set, you can be sure the circuit is still operating as new.

Some things that can affect speed are; low throttle setting, pump wear, motor wear and filter conditions.  You have the tools to check the pressures, so here we go.

Take all test readings from port M1A, for the main conveyor, and M2A for the feeder.  Ports M1B and M2B are load sense ports used by the factory.

There are two pressure settings for each pump.  They are the Low Pressure, a.k.a. “stand-by,” and high pressure.

 The illustration is a TB-110.  The TB-80 is controls mount the same way, but the TB-130 and TB-600 have the controls “laid down” so the volume control knobs face you.  As a result, the TB-130 and TB-600  M1A and M2A  ports face downward.

You will need the 60 bar and 400 gauges, supplied with the Telebelt, to check the pressure settings.  ALWAYS connect the 400 bar gauge first, since there could be more than 60 bar in the circuit of a belt that is not moving, depending how the belt cards are set.

Gauges can be connected when there is pressure on the circuit.  It is not necessary to disengage the PTO’s to connect the gauges.

Pressure adjustments can be made at idle, or just above.  It is not necessary to go to full RPM.

Compensator adjusting screws will have either a lock nut and Allen screw, or an acorn nut that, when removed, exposes a lock nut and Allen screw.  Release the lock nuts and turn the screws IN (clockwise) to increase pressure, or OUT (counter-clockwise) to decrease pressure.

On Mack Telebelts, the front pump on the driver’s side is the main belt pump.  The pump attached to it is the feeder belt pump.  On Telebelts with a transfer case (TOR, Sterling) as well as TBS units, the first pump is the main belt and the second is the feeder.

Setting low pressure, main belt:

  • Start the Telebelt and engage the PTO’s.

    Method 1: DO NOTreset the e-stop.  If the motor control valves are energized, false readings are possible if the belt card zero screws are set too high.  Open the load sense shut-off valve manual bypass.Alternate method:  Reset the e-stop, but disconnect the motor control valve connectors, pull the belt cards out, or remove the belt card fuses.  This will turn the load sense valves on, electrically.  Opening the bypass is not necessary.

    Either method will produce the same results; 1. Load sense shut-off open and 2. no power to belt control valves.

  • Connect 400 bar gauge to M1A and make sure pressure is below 60 bar.
  • Switch to the 60 bar gauge on M1A and read the pressure.  Compare this to the original reading on the test sheet in the front of the manual.  It will probably call for 20 bar.  If the correct pressure is not read, adjust the low pressure setting screw.
  • Remove the 60 bar gauge.

Setting high pressure, main belt:

In order to check high pressure, you have to cause the function to go to relief.  In other words, you have to stall the belt motors or block the flow to the motors.  You can cap the hoses to both motors, or reverse the lines to one of the motors, which cause them to turn against each other.  I prefer the latter.

  • Let the air pressure off the hydraulic tank (TB-105 and TB-110 only)
  • Reverse the hoses to one of the main belt motors.
  • Re-pressurize the hydraulic tank (TB-105 and TB-110 only)
  • Connect 400 bar gauge to M1A
  • Start the Telebelt and engage the PTO’s
  • Reset the e-stop
  • Turn the main conveyor on.
  • Gauge reading should be 280 bar.  Adjust as necessary.
  • Shut Telebelt off and de-pressurize the hydraulic tank (TB-105 and TB-110 only)
  • Return motor hoses to their original position
  • Re-pressurize the hydraulic tank (TB-105 and TB-110 only)
  • Remove 400 bar gauge

Setting low pressure, feeder belt:

 Use the same procedure as for the main, except test at M2A.

Setting high pressure, feeder belt:

Use the same procedure as for the main, except test at M2A.  To block flow in the circuit, cap the pressure line going into the feeder motor.  This is the line that DOES NOT have a “T” in line.

Current production pressure settings – November 2010

 Standby Pressure

Main conveyor pumps except TB(S)-130/600 = 20 bar,  TB(S)-130/600 = 25 bar

All feeder belt pumps = 20 bar

All boom/outrigger pumps = 22 bar

High Pressure

ALL PUMPS = 280 bar.

 

Placing Dirt With a Telebelt

Placing Dirt With a Telebelt

Placing dirt can be a problem. Depending on your area, you could be dealing with clumps, stumps and lumps, among other things.  Moisture content can also be your enemy.  Here are a few tricks.

If you are using the aluminum Front End Loader Hopper (part # A306000), try putting 2×4 blocks under the front pads. This will raise the discharge end of the hopper and expose more belt to take the dirt out and reduce “bridging.” You will have to tie the front of the hopper down to the rail, to keep the blocks from falling out.

This shows a Front End Loader Hopper with an electric vibrator (part # A309849) installed, powered from the accessory plug on the Telebelt.  The operator has also raised the back of the hopper to expose more belt.  Note the chain and binder in place of the rear pin.

Also note the feeder is set up with the legs down.  This is the best way to keep spillage from jamming the tail pulley. Some operators of the small loaders complain they can’t see in the hopper.  They’ll get over it.

The best hopper to use with large loaders is the 3-Yard Hopper (part # A300042).  When using this hopper, keep the bottom of the skirts even with the top of the concrete hopper.  Don’t lower the skirts into the hopper, as that blocks the flow.  When the lower hopper fills, flow will stop.

 

 

View at discharge:  The ideal setup is the 3-Yard Hopper feeding a Low Profile hopper (part # A306001).  The transfer opening is large enough, plus you are not beating the concrete hopper to death.

 

 

 

Side view of Low Profile Hopper under 3-Yard Hopper.

 

 

 

 

 

 

 

An optional hopper grate (part # A309979)  is available for the 3-Yard Hopper.  It is strong enough so loaders can break up clumps.

 

 

 

 

 

It’s hinged, on the front and has notched legs in the
rear to set the angle of the grate.

Belt(s) won’t run? I’ll bet it’s not the pump.

Belt(s) won’t run?  I’ll bet it’s not the pump.

 1 of 3 – Mechanical

This is the first of three articles about Telebelt belt-related problems.

From time to time, I get calls involving a belt that won’t run, or runs very slowly.  The call I like the least is, “My feeder (or main) belt quit running.  I replaced the pump, but it still won’t run.”

With over 800 Telebelts in the field, we are looking at more than 2,100 piston pumps.  We don’t hear of pump failures very often.  Even if we go back to the Super Swinger 105s, of the early 90s, many are still running original pumps.

So, again, I’ll bet it’s not the pump.

Rule # 1 – Check to see if it will run with manual control.  If it will, the problem is probably electrical or in the radio.  If not, it’s mechanical or hydraulic.

Things that stop belts: 

  • Mechanical problems
  • Electrical problems
  • Hydraulic problems
  • Truck or engine failure.  This is beyond the scope of this series.

Let’s deal with mechanical problems, since they are the easiest to spot.

Are the PTO shafts turning? 

  • Actually look at them.  I once spent an hour on the phone with an operator who has just moved and set back up and his belts wouldn’t work.  I finally got him to look under the rig, where he found a pump drive shaft lying on the ground.
  • Is the PTO engaged?  Snow and ice can jam a PTO linkage.  Pins can fall out.  Air lines can leak.  PTO shaft gears can strip.

Do the hoses jerk, like there is pressure?  Does the belt move a little?  Put a pressure gauge on the test port.  If there is 280 bar, and nothing is moving, look for:

  • A seized 5” pulley
  • A seized feeder drive pulley
  • Over-tensioned scraper – Yes, that can stall a belt.  It can also stall a belt that is heavily loaded.
  • Rocks packed at tail pulley (feeder) or drive pulley (main).
  • Rocks packed at the heel of the arm back from the tip section (arm 3 on a TB-105 or 110, arm 4 on a TB-130).  There is supposed to be a v-scraper there to guard the close clearance between the heel pulley and the steel end frame.
  • Feeder motor hoses kinked.  Active (hydraulic lift) feeder machines (TB130, 80 & 110) can do this if the feeder is slewed more than one time around.  On 105’s, feeder lines can get pinched in the transfer.  Also check 105 feeder line quick connects to make sure they have not backed out.
  • Is more torque required?  This is as much a hydraulic issue as mechanical.  Most Telebelt feeders operate just fine with 130cc motors.  Belts that are heavily loaded, paving for example, might require 160cc motor.

Do you think oil is flowing but there is not much pressure? 

  • Feeder – check for stripped drive pulley collet or broken motor shaft.
  • The Main has 2 motors that plug into splined adapters welded into the ends of the pulley shaft.  If the welds on an adaptor break, that motor will be free to spin.  You will hear oil going through the motor.  Operators have finished pours by capping the lines to the “bad” side motor, thus forcing the other motor to drive the pulley.
  • Check main motors for broken shafts.

Are the belts tight enough? 

  • Feeder belt pulleys are more likely to slip, especially if they are the old-style steel-lagged pulleys.  Maintain feeder tension at 1,500 to 1,800 PSI.
  • Once in a while, you will find a ready-mix driver that will wash what he spills.  If he gets the back side of a loose feeder belt wet, the drive pulley might slip. 
  • Main conveyor pulleys are less likely to slip, even if the belts are real loose.  Worn or missing drive pulley rubber lagging leaves a steel surface that will slip.  Maintain main belt tension at 1,000 to 1,200 PSI.
  • Keep lagging grooves, on main and feeder drives, free of grout buildup.

 

 

Q&A Session – Question 3: Why use Putzmeister rollers in my Telebelt?

Using the right rollers in the correct position is very important to the life of the belts and the over-all performance of the Telebelt. Once again, the location and design of our rollers are a product of years of experience and practical application. Building a “cheaper” roller is not always in the best interest of practical application.
This can be the case if roller design and fabrication cost savings end up producing a design that threatens the integrity and longevity of more costly components, such as belts. This can also be the case if new approach or design just does not perform as well. As an example, our hopper roller design prevents the belt from being “pulled” down between the roller and into the U-shank brackets when tensioning the belt (see images above and below).


Our roller caps are a simple and re-useable design that has worked rather well over many years. People have tried to substitute these caps with other designs without the same level of success, resulting in one-time-use and often missing roller caps (see left and below).

Setting Telebelt Feeder Lift Pressure Switches

Function:  When the main conveyors are slewed, the brakes on both the feeder and the main release.  If this happens with the feeder off the ground, the feeder will:
a) swing behind the main conveyor like a real long counterweight, or
b) take off downhill if the machine is not level.

The feeders are raised hydraulically, but they lower by gravity as the oil passes through an orifice.  The feeders must be fully lowered for the mains to slew.  It looks like you are “powering down,” but you’re just letting the cylinder and rails relax.

If there is enough pressure in the feeder elevate circuit, the (NC) pressure switches open and break the connection to the slewing valve.  The WBV valve still goes to the “boom” side.  One switch disables slew right and the other disables left, and they are both connected to the feeder lift line through a manifold block.  No oil flows to release the brakes when the slewing valve doesn’t throw.

Symptoms:  Main will not slew left, but slew right works, or vice-versa.  It’s very rare for the main to not slew in either direction because of pressure switch adjustment, but it can happen if there is enough pressure on the system.  All functions work manually.  Cable remote makes no difference.

 “Field Fix” (to complete a pour):

  1. Make sure the feeder is down fully.  All pressure must be off the feeder elevate cylinder.
  2. After confirming feeder is firmly on the ground, try manual control.  Make sure to move the WBV (selector valve) andthe slewing valve.  If it still doesn’t slew, the problem is not the pressure switch.  If the main does slew, options are:
    1. Operate slewing manually to finish the pour.  Keep the feeder firmly on the ground while slewing the main.
    2. Bypass the pressure switches by:
      1. Removing the plug connector from the top of one the switches.  On a 110, it might be necessary to remove the fan shroud to do this.  If the problem is unchanged, that is the correct plug.  If it now won’t swing either way, replace that plug and remove the other one.
      2. Put a jumper wire between pin 1 and pin 2 of the plug.  A piece of tie wire will do.  Do not reconnect the plug, but tie it out of the way to keep it from shorting.
    3. Alternate bypass – Jump X10-17 to X10-18 for right or X10-19 to X10-20 for left.
    4. This is a temporary fix and permanent repairs MUST be made before taking the unit out again. 

     

    Procedure for Setting Telebelt Feeder Lift Pressure Switches

    NOTE: THIS PROCEDURE CAN ONLY BE PERFORMED WHEN THE SWITCH IS INSTALLED IN THE CIRCUIT. THESE ILLUSTRATIONS ARE MERELY FOR SHOWING THE SWITCH.

    The feeder lift pressure switches are installed to prevent the main boom from slewing when the feeder is off the ground.  This is a safety system.  The switches are installed in the feeder elevate hydraulic circuit.

    To set the switches, you need a continuity tester, 1/8” Allen wrench and a flat-head screwdriver.

    Procedure:

      1. Support machine with outriggers.
      2. Unstow the feeder from the rest on top of the main boom and slew feeder to side of machine.
      3. Lower empty feeder (NO HOPPER OR ATTACHEMENTS) until the feeder legs are 1 to 2 feet off the ground.
      4. Turn off the remote.  The truck engine can also be shut off.
      5. Remove wire connection plugs from both switches.
      6. Remove small brass screw adapters from both switches.  These are the adapters that the plugs screw in to. 

      1. Connect a continuity tester to terminal #1 and #2 (terminals are labeled on switch and plug)

      1. With 1/8” Allen wrench, turn the pressure adjustment screw in, (screws are located under the brass screw plug you removed), until you get continuity, then back screw out until you loose continuity.  From this point, back the adjustment screw out ½ turn more, this is your final setting.

    1. Repeat steps 8 on the other switch.
    2. Reinstall the brass screw adapters and wire connection plugs.
    3. Restart the engine, reset the remote and test the settings by lowering the feeder to the ground, then lift main boom out of the boom rest and slew main boom to the right and the left.  The main boom should slew.  Then raise the feeder off the ground and slew main boom right and left.  The main boom should not move.

BOOM PUMP: Proximity Switches

Your Putzmeister boom pump uses proximity switches (aka prox switch) to cycle the pump. Some quick tips to keep them from being a misunderstood part on your pump.

 

What might go wrong?

Prox switches are screwed directly in to the drive cylinders and are subject to high pressure hydraulic oil. It is common to over tighten them, they take 14 foot pounds of torque which is a relatively low torque. Because they are in the pump hydraulic cylinder subject to high pressure oil they are quite often over torqued, this distorts the switch and it will fail early or not work correctly. The prox switches have a high pressure seal to handle the pressure subjected to them.

Next prox switches are grounded through the cable not the cylinder, so to test the system you can take a new switch, plug it in, touch it to metal and it will trigger. The switch works from magnetic principle, the piston is steel and the switch is triggered by this steel piston passing under it.

PMA Prox Switch Testing

PMA Prox Switch Testing

Deciphering the Light and Wires

On top of the plug you will see two LEDs one is green and one is yellow, The green one indicates that power is getting to the switch, the yellow one is the trigger signal that indicates the piston is under the switch sending a signal to the relay.

The prox switch wires go back to the distribution box, this box combines the signal to send it to the stroke change relay, LEDs are located at this box to tell you if they are working, you might have four or six switches on the standard units.

We encourage you to watch the lights when you are cycling the unit to clean the water box. You should see the yellow LEDs flash when the piston is passing under the switch; you have two switches at each position. They are working together as a backup which means if one fails you are still pumping.

PMA Prox Switch LED Lights

PMA Prox Switch LED Lights

Ways Prox Switches Fail

Switches can generally fail two ways, the yellow LED does not turn on when the piston passes under it, this is the most common failure. They can also fail by being stuck on. The yellow LED will be on even though the piston is not under the switch. In the first case no action is necessary, but if the switch is stuck on it will need to be disconnected from the system as it will interfere with the cycling of the relay. Simply unplug the one that is failed on, and resume pumping.

We all know that if it can go wrong it most likely will, this is the reason for the redundant-style system. However, quite often due to lack of maintenance or lack of understanding one switch will fail, then at some point the other switch will fail and now you have a problem. So familiarize yourself with the system and check it frequently so you can avoid being down due to prox switch failure.

PMAProxSwitch2

The pictures show a model used in the Putzmeister Service School class room to demonstrate the switches and the cylinder position, as well as, testing a switch not installed on a unit.

BOOM PUMP: Having E-Stop Issues? Simple Things to Check.

This relates to standard 12V units as well as early European 24V units.

Every component in your Control (aka Combi) Box should be labeled; age and changing parts without putting a sticker on the new part can lead to problems. In the image the decal shows 10A17, yours might say 6A17.

E-stop

Deciphering the Number

The first number, 10 or 6, is the page number of the schematic that you will find this component on. All components in the Combi box work this way; for example, 6F76 is the fuse for e-stop on page 6. The page number of the schematic varies with the options a unit has, or the amount of revisions to a particular unit. We can go into revisions later.

The letter, A, is the code for the part, A= Assembly, F=Fuse, S=switch, K=relay. Notice a German unit’s code letters are the same as English.

The second number, 17, is the assigned number for the device. Notice 10A17 and 6A17 are the same part just different pages in the schematic.

So You Are Having Issues With The E-Stop? A Quick Test Will Reveal Why.

Look at top left and find Terminal A1 (+), also in the lower right find A2 (-), putting a voltage tester at these 2 points will tell you if you have voltage. We NEED to use a voltage tester not a test light to see how much voltage we have here. Note: The red locking paint might need to be cleaned a little at the screw to get a good test.

For this relay to reset and hold you need to maintain 12 VDC, these 2 pins are powering a coil that is rated for 12 VDC. If you hit an E-stop button on the unit or turn off the remote, the voltage disappears and the relay unlocks, the 2 green lights go out and nothing works. So if you have no voltage here check the E-Stop buttons on your remote and if the local/remote switch is in the center position. A quick test for checking the remote is to set the local/remote switch to local and check for voltage. If the E-Stop resets and you have 12(+- 2 VDC), you have a remote issue, try your hard wire remote.

As previously, mentioned, always test with a voltage tester not a light, also test using the A2 (-) pin for ground, this is the ground the relay is using, If the wire from A2 to ground is bad the relay won’t set either. A quick check for this is: positive lead on A1, negative lead on A2 and look at the result, then move the negative lead to main ground in the Combi Box and look at the result. No or low voltage at A1 and A2, and 13.6 at A1 and the main ground point tells you that your problem is a bad ground from A2 to the main ground, follow that part of the circuit.

Voltage Drop

Most of the time the issue is voltage drop. I get a comment like “I get the E-stop to clear and start pumping then I hit 2 or 3 boom functions and it goes back into E-stop. If I do one function at a time it stays on.”  To avoid this or find the issue you need to test for voltage drop at A1. You can do this with the boom closed just don’t put the transmission in gear; have someone assist you with the remote, make sure the engine is running, PTO ON, not in gear on the transmission, this way you can activate the electrical components and not bend boom arms. That’s a different Tricks of the Trade post.

Check for the voltage at A1 then clear the E-stop by honking the horn, turn on the pump and see the voltage drop a little, next hit A arm, it dropped a little more didn’t it,“ then B, then slewing, then tip. Each function you activate is more draw on the circuit and at some point the E-stop relay will drop out. Not from a bad E-stop button but from voltage drop.

The problem is current flow. Look for loose or corroded wires in the E-stop switches or in the cable powering the remote receiver. Open the boxes and look at the wires, are they loose? Give them a little yank did it pull out of the terminal or sleeve? One common source for resistance issues is corrosion in the cable due to washing the pump with acid. Acid loves concrete, copper and chrome, it is not recommended to use acid to wash pumps. I have seen it turn the wires green as far as 3 feet inside the plastic coating, a major source for voltage drop. Poor grounds for the Combi Box and poor power from the truck are also big issues as the unit ages.

Take the time to do this easy test, if your voltage drops you can dig a little deeper to locate the problem and avoid future issues by resolving the problem now.

Do  Not Bypass E-Stop.

This is also the time to mention that bypassing the E-Stop is a serious problem, if the power is not at the A1 pin then even if bypassed the remote won’t work. This is due to the fact that the remote is being powered with this same circuit. So bypassing is not the best way out of problems it presents major safety issues and most likely won’t get you up and running on the remote.

As mentioned in the beginning, this is the basic start to troubleshooting the 12V Combi Box. If you have a 24 V ZMSK box the E-stop circuit is a little different, contact the Service Dept (800-890-0269), e-mail me (woodsa@putzam.com) or comment on this post and we can go deeper into the particulars.