What kind of problems can occur with concrete pump machine?

Most commonly, operator error is the cause of problems with concrete pumps.
Pump line blockages can also occur and these are due to either operator error, a problem in the concrete mix design or insufficient mixing of all the ingredients used to make concrete, which can cause segregation of the mix. A delay in placing concrete due to traffic congestion or problems on site can also result in concrete pump blockages as can hot weather resulting in concrete setting too quickly and causing an increase in pressure in the pump.
But, if managed properly and maintained well by a trained and experienced operator a modern concrete pump should not present with too many problems.