water flow

can you help? There is a constant flow of water coming out of the drain hose and you can hear a humming sound .

What kind of system are we talking about?
Could be that one of the seals or the piston needs to be replaced.
Could also be that the system has stopped in a spot other than the service spot..
More information is needed to help in figuring out why it is doing what you are talking about.

Most units have a bypass so you can stop the water flow.