The homeowner, or his agent, should test a relief valve at least as often as the manufacturer and code recommends. The agent should ask the homeowner for permission to test the relief valve, tell the homeowner why he is testing the valve and give a recommendation to call a repair service if it does leak. The agent in this case did none of these basic courtesies, so the owner wrote a question here.
The proper procedure is a matter of public safety. It is unknown if the inspector had sufficient training to know what he was doing, the safety implications of opening the valve and allowing it to leak without repair. If he did, he was at least discourteous in not informing the homeowner of the danger, and I feel he was malfeasant in performing the act without safety instruction to the homeowner.
The inspector didn’t have to tell the homeowner how to replace it. The inspector may be creating a dangerous situation by encouraging the homeowner to do it himself. As simple and easy as the task appears, there are some real dangers to an inexperienced amateur.
A plumber is licensed to perform service that is potentially dangerous. The purpose of the apprenticeship is to keep the new tradesman in contact with experienced tradesmen for enough time to develop a respect for the safe practices documented in the codes and manufacturer’s instructions. An apprenticeship is a rare opportunity that few experience. The attitude of care for the customer is the basis of good business.