Usually the meth-makers pick on agricultural ammonia sources but they occasionally go to a cold storage as well:
“The attempted theft of ammonia appears to be the cause of a leak Tuesday morning at the Washington Cold Storage facility in Kent…” —Kent Reporter
I’m hearing that this was from a charging (sometimes called a fill) line outside the engine room. If that’s the case then there is a lesson to be learned here. One good option is to pipe your charging line like this:
You keep the valves on the left closed unless your actually adding charge to the system. The valves on the right are outside the building and although they could be opened by would-be thieves, they wouldn’t get anything for their efforts. The pressure indicators in between the closed valves are to ensure you aren’t leaking liquid into the the space between the valves and to give you a convenient location to purge from if needed.
I’ve also seen people encasing these outside valves in a locked metal cabinet which is not a bad idea at all. How do you protect your fill valves from troublemakers?