Probably not going to be able to give a comprehensive answer here as there are many variables, such as would it be a dupicated system or a shared system (pressurised hyds on one side of the supply system and pressurised pneau on the other)? Would it be a "one - shot" emergency system or a complete alternative control system? There a a good number of other set-ups to consider too, but regarding valve flutter it would logically be held in the favoured position by a solenoid or similar, in the event of a failure it would be selected manually, or if a pressure drop occured on one side or the other then a pressure sensor should instruct to solenoid to release and yield to the system with positive pressure. The problem with that if using the same lines is that you could very easily end up dumping your air out of the same hole your fluid went out of. A pump failure would not present the same problem though, as there would be no breach of the pipework, and a wise system design would have a pump failure alarm built in as well as a pressure loss indication. I'll stop there for two reasons:
1. I could go on all night.
2. I'm almost certainly well out of date with my systems knowledge.
Others will advise better I am sure.👍
Last edited by TLDNMCL; 12th Jun 2019 at 18:03.
Reason: Hadn't finished!