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

How to Use Backup Controls

Understanding the functions on the manual backup valve bank.

Valve Bank: Most common with Gen 3 or Monochrome Screen, can also be Gen 4.

1

Stroke manually:

Short Oval Knob Handle: strokes drive cylinders. Push or pull handle and hold for the duration of one stroke. Truck must be above 1200 rpm.

Tall Ball Knob Handle: shifts S-valve. Push or Pull and release. Holding in position is not required.

2

Blue: Accumulator dump valve, manual operation button.

Red: S-valve cycle valve, electric coils driven by CCU, manual palm buttons on each end of valve.

Green: Accumulator pressure relief “Backup” 250 bar (3,625 psi)

 

 

Manual Valve Bank: Gen 4 Model3

Green: Drive cylinder stroke valve. Push or pull and hold in position for the full duration of one stroke.

Red: Accumulator dump valve manual override.

Blue: S-Valve cycle valve.

Hard/Soft Shift for S-Valve

4

Hard-Shift: In-line (shown)

Soft-Shift: Closed at 90°

Accumulator Bottle:

5Accumulator Bottle: 4 Liters

Pressures:

6

WP Water Pump Pressure: 190 bar (2,755 psi)

RW Auger Pressure: 160 bar (2,320 psi)

Manual Auger and Water Pump Valve Block: Applies to Both Generation 3 and 4

7

Green: Manual valve for water pump

Blue: Manual auger forward valve

Red: Manual auger reverse valve

8

Green: Manual valve for water pump

Blue: Manual auger forward valve

Red: Manual auger reverse valve

To operate auger reverse, both the Red and Blue coils or valves must be engaged.

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.

Putzmeister Boom Valve Coil Tips

I have a little more homework and Info for you guys.

Over the years we all have had issues with setting and adjusting the boom speeds, either to fast or to slow, the function can feel rough or jerky or even black and white. Some have tried to repeatedly adjust the boom speeds with the Teleteach buttons or battery to no good result. If you need to constantly teach the remote you generally have a remote issue, other than oil temp variance the settings should stay relatively the same, week to week.

But there is another option you can easily look at for these types of symptoms.

The joystick is communicating to the coil on the boom valve, the coils can wear out, as they draw more Amps the range of motion changes, thus the need to adjust from time to time.

The plunger spool’s that the coil’s drive can also get sticky or gummed up over time. The images below will show you how to remove and clean the spools, test the coils, and look for issues. The coils are the same from valve to valve, so they can be moved around. BUT BEWARE, on units equipped with EBC this is not advisable, the computer is set to work with the coil and valve matched, adjustments to the EBC programming might need to be reset if coils are changed or moved around.

The leading problem we have with Mother Boards on 24 V systems is over Amping the fuse. If an outrigger or Boom coil is bad it can draw high amps and blow the fuse.  DO NOT PUT IN A BIGGER FUSE, RUN THE FUNCTION MANUALY AND FIX THE ISSUE.

 Other issues that can give you problems with these spools and other components on the unit are cheap oil, dirty oil, water in the oil, and high “TAN” numbers. These all lead to corrosion and sticky components all over the unit. Phantom issues that come and go are usually related to the oil and its condition. Do oil sample testing to ensure the condition of your oil. Oil that has water in it looks milky ONLY after it has become saturated with to much water, clear oil in the sight gauge can still have to much water in it. The only way to know for sure is to have it tested.

 

I hope this helps and brings out even more questions, please feel free to ask online or call PM CSG at 1-800-890-0269, or myself at 360-600-5695, or reach me by email at woodsa@putzam.com.

 

As always, be safe and keep the rubber side down.

Travelteck

 


PICTURE 1:
Coils are located behind the Boom valves. All the coils on a unit are the same, they can be swapped if needed.

Example: the Coil for the Boom / Outrigger is having issues, the Coil from the B arm could be used to swap with the Boom / Outrigger to get through a job.

Units with EBC rely on adjustments to compensate for coil resistance. On unit’s equipped with EBC you can change coils but EBC might need to be readjusted for the new coil. Without EBC there would not be an issue, but swapping coils to diagnose is not recommended on functioning EBC units.

High resistance values or shorted coils are one of the leading killers of Motherboards, NEVER over amp a fuse to make a function work even if it is for a “short time”, the motherboard will become the next fuse. Remember, everything you turn on with an electrical switch can be run MANUALY.

Q&A Session- Question 1: Why are there 16″ scraper blades on an 18″ belt?

ANSWER:

Telebelts are equipped with “crowned” pulleys. Slightly tapered pulleys allow for easier adjustment when training or tracking of the belt. This is especially true on faster moving belts such as those used to place concrete. This feature is even more important for the purposes of belt training when the conveyor is telescopic, multi-section as is the Telebelt. Trust me, flat pulleys were tried in the very early design and training the belt throughout the telescope range was impossible! Even when only half the pulleys were flat it was still an impossible task to track the belt.

When a tensioned belt wraps around a tapered pulley it leaves that pulley with its edges opposite the pulley taper. That is to say the belt comes off the pulley in a crescent shape, with edges of the belt somewhat lower than the center (see diagram 1, left). For this reason, using a scraper as wide as the belt wears out the edges of the belt pre-maturely.

Getting proper surface tension between the blade and the belt also becomes more difficult because the force being used to pull the scraper against the belt has to deflect the edge of the belt that much more before adding any appreciable force in the middle or center (once again see diagram 1). This problem becomes worse the further behind the pulley the scraper is mounted. This is because you now have to deflect the tensioned belt in both directions, width and length, before significantly effecting the tension of the blade against the surface of the belt (see diagram 2, below, – upper right-hand corner).

You may have read in some of our past literature words like belt “flutter” and scraper “bounce”. These are also symptoms of the scraper being too far behind the pulley. A mistimed or an unlucky scraper bounce can catch a rock and render the scraper useless, or worse wreck a belt! A “fluttering” belt will not run clean. In all cases, an 18” blade on an 18” belt makes every condition or symptom worse!

When you hear customers saying things like; “I just can’t get that thing to run clean no matter how much I tension the scraper!” or “My scraper springs are stretching and I have run out of adjustment on the scraper chains or T-handles!”, the main two causes are scraper blades that are too wide and scrapers that are too far behind the pulley.

Besides these problems, you have to ask why do you want to clean the belt out that wide anyway? The tunnels, even on a machine set up for high volume placing, will only expose a max of 12” or 14” of belt, and most are set up with only about 9” to 11” of belt exposed. The material leaves these transfer skirts on a “V” shaped belt and the material profile on the belt doesn’t reach to those outside edges of the belt. If the concrete is so liquid that the material profile within that the normal “V” shape or in the discharge transition area reaches the edges of the belt, more than likely the belt is running too slow or there is too much belt exposed between the skirts or both. The bottom-line is that on a machine that is properly set up and run, there is nothing out on the last inch of belt on both sides to clean!

The only historical leg to stand on in defense of same width blades and belts is that the earliest Telebelt model I mentioned earlier ran 16” blades with a 16” belt. There are couple reasons for this. Firstly, that machine ran 4” pulleys and they just were not as aggressively tapered, lessening the severity of the systems described above. Second, and the most reality based reason, is that the manufacture just never got around to making a 14” scraper blade (assigning a whole new part number, etc). Every other concrete conveyor built used the ‘2” narrower than belt width scraper blade’, up to and past 48” belts. So, the only machine that ever used same width scrapers did so because the manufacture just never got around to making a 14” blade with some of its components allowing it to get away with that oversight. That doesn’t make it correct!

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.

Telebelt Receiver Fuses

The e-stop circuit of Telebelts includes the HBC 735 radio receiver.  Actually, the e-stop circuit supplies power to the radio receiver. 

The images below, A370160 Pg 4 and Pg 5 show the circuit. To view at a larger size, click on each photo individually and they will open in a new window.

The 12V supply (red) goes through the e-stop stations to X81 pin 13.  X-81 is located on the right-hand (hinge side) of the control cabinet.  The power then goes through a fuse in the radio receiver and returns to X81 pin 5, and then through the e-stop stations to 4A17, the e-stop relay. 

 

 

 

This image shows the pin locations on X81.

 

 

 

 

 

 

The image shows the inside of the 735 radio receiver.  There are 4 fuses called out in the image, and their reference numbers correspond to the reference numbers in the image that follows.

 

They are:

42 = Power supply primary – 6.3A

43 = Power supply secondary – 1.0A

44 = Proportional output card – 12.5A

45 = E-Stop card – 4A

 

 

All of these fuses remove by pushing the end cap in slightly and rotating it to the left.  When the cap releases, a spring pushes it out a little.  The fuse will be attached to the cap.  You might need a coin or flat blade screwdriver to remove the cap.

 

RULE #1 – The problem is NOT in the radio system

 

Symptoms of a problem:  

 

E-stop will not reset and there are no LED’s lit on the receiver.

 

FUSE FAILURES IN THE RECEIVER ARE RARE.  Make sure you check all the way through the e-stop circuit (SEE RULE #1).  A blown 4F17 or a bad e-stop button causes the same symptoms.

 

If you have no power at pin X81-13, the problem is NOT in the receiver.  If you have 12V at X81-13 and zero volts at X81-5, check fuses 42 and 43 in the receiver.  Either one of these fuses, when blown, cause these symptoms.

 

Before replacing any fuses and turning power back on, find the short.  Likely places are faulty e-stop buttons or their boxes, or cable shorts between X81 and the radio receiver.  The 90’ cable can be substituted for troubleshooting purposes.

 

E-stop will not reset and there are LED’s lit on the receiver.

 

SEE RULE #1.  There are many possibilities, including:

  • Remote switch problem.  Verify with cable remote
  • See control box schematic:
    • Blown 3F64
    • 4K69 or 3K275 bad or unseated – confirm by flashing 4A17-T33 to 4A17-T-34
    • 4A17 connections bad
    • 4A17 defective
  • Problem with receiver cable from X81 – use 90’ cable to confirm

 

If all else doesn’t correct the problem, check 4A fuse #45 on the e-stop card.  If the receiver cover is off, you will see the “light show,” but attempts to reset will just cause relays on the card to click.

 

E-stop will reset and there are LED’s lit on the receiver.  Only non-proportional functions (toggle switches) work, but moving joysticks only cause the WBV (Boom/Outrigger) selector valve to move.  The actual function levers do not move.

 

RULE #1 might not apply.  This is opposite from when the pilot valve relay is bad, or when you turn on the transmitter but don’t reset.  In that case, the function levers move but the WBV valve does not.   Just to be sure, use the cable remote to confirm the radio problem, then check the 12.5A fuse #44 on the proportional output card.

 

Before replacing any fuses and turning power back on, find the short.  Likely places are faulty cables or plug connectors on MBC valve, or cable shorts between X81 and the radio receiver.  The 90’ cable can be substituted for troubleshooting purposes.

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.