The purpose of a combiner valve that is used for an excavator ...

[ashley]

The purpose of a combiner valve that is used for an excavator hydraulic system it to:
 
  a. increase the main relief pressure for heavy lifting
 b. combine the two main pump flows for certain high flow functions c. combine the pilot oil pump with one of the main pump flows
 d. combine the bucket and stick circuits for faster digging

Question 2

A hydraulic system that uses a pilot oil system will:
 
  a. Use lower pressure pilot oil to move the actuators slower b. Always have a pilot oil pump
 c. Use lower pressure oil to move the main control valve spools
 d. Will always have its relief valve set 1000 psi lower than main system pressure

[fauacakatahaias]

Answer to Question 1

D

Answer to Question 2

C

[ashley]

Thanks for the timely response, appreciate it

[Joy Chen]

Wow, this really help