Anshu18:
Firstly, the title of this thread is “Reciprocating Compressor Unloader Valves” and has nothing to do with reciprocating compressor recycle valves. The two are distinctly different animals. You should not highjack a thread in our Forums, as explained in our Forum Guidelines. You should have started a new thread on your specific topic.
Secondly, a succinct and proper response to your query could easily be the answer of our learned and experienced colleague, Bobby Strain, who in thread Fail Mode Of Recycle Valve In Reciprocating Compressor (found at http://www.cheresour...ng-compressor/) stated: “My philosophy is to always fail a valve closed unless there is good reason not to do so.”
Additionally, a complete and detailed response to this particular topic of employing a Fail Open design on a reciprocating compressor recycle valve was discussed and explained in detail in the thread found at: http://www.cheresour...ressor-recycle/.
A reciprocating compressor should always be started (and stopped) in the completely unloaded condition - unless advised otherwise by the compressor manufacturer. This is so not because I say it, but rather because that is what the basic design of a positive displacement device requires. The torque required of a natural gas engine is one thing; but there are other considerations that must be applied - such as process conditions, the limits of the compressor’s mechanical design, potential high pressure in the suction side, etc..
Without thorough knowledge of your process application the Forum is unable to state whether what your supplier states is the correct and proper way to start (and stop) your reciprocating compressor. To further treat with this topic, please start a new, specific thread on this subject, supplying complete and detailed data and information.