Machine was working fine then suddenly as if someone flicked the switch to stop pumping it stopped. It would not forward pump only reverse pump so using the manual over ride I emptied the load of concrete and got back to the workshop. After some basic trouble shooting I replaced the solenoid for forward pumping which is on the lever chest in the side locker. This fixed my problem (or so i thought) and I pumped out 1000l of water in the yard just to make sure I was good to go. However today I arrived onsite set up the pump, primed out with jelly and pumped 0.5m3 of concrete and same problem again.

Anyone with a similar experience? Im beginning to think its the actuator which the solenoids are bolted too?

Did you call Schwing, they are normally really good at helping people. 

Please call the Schwing tech support line at 1-888-SCHWING and we can assist with your issue

You were right to go to solenoid but checking solenoid doesn't give certain answer it just narrows it down to less possibilities. So realistically its going to be either proximity switch, solenoid coil, the plug socket that the solenoid it connected to, the breaker or fuse behind panel for forward pump directional valve, and lastly buildup in swing tube. start with changing or overriding each of these eliminating options as you go and you will wind your problem. each of these parts work together in order to pump so if one is out, you can't pumping without overriding or changing. sometime process of elimination is most efficient.

while waiting for a second truck i shut the pump off. go to restart it would turn over but not fire up. 

after going to the duetz shop they discovered the large twist lock wiring harness came lose.

some times its really simple but it takes a second guy to check it out.

Troubleshooting Schwing Forward Pump Failure

This sounds like a classic intermittent issue with the forward pumping function on your Schwing. Based on similar cases reported on ConcretePumping.com, here are the most likely culprits:

Most Likely Causes

1. Proximity Switch Issues

   • The proximity switch that detects the end of stroke may be faulty or misaligned
   • Since it works in reverse but not forward, this suggests a problem with the specific proximity switch for that direction

2. Electrical Connections

   • Check the plug socket where the solenoid connects
   • Look for corrosion, loose connections, or damaged pins
   • Vibration during operation can cause intermittent connections

3. Solenoid Coil

   • While you replaced the solenoid, the issue could be with the coil itself
   • Test the resistance (ohms) of the coil with a multimeter to verify it's within specs

4. Circuit Protection

   • Check the breaker or fuse behind the panel specifically for the forward pump directional valve

5. Mechanical Issues

   • Inspect for buildup in the swing tube that might be creating excessive pressure in the forward direction

Troubleshooting Approach

As suggested by saltier555 on ConcretePumping.com, use a process of elimination:

• Start by checking each component systematically
• Override components one by one to isolate the issue
• Remember that these parts work together in sequence, so one faulty component can prevent pumping

Expert Support

If you continue to experience issues, Schwing's technical support can provide specific guidance:

• Call the Schwing tech support line at 1-888-SCHWING

This pattern of working temporarily after repair but failing again under load strongly suggests an intermittent electrical issue or a pressure-related problem that only manifests under operating conditions.