You do this work and don't know? Can you ask the people you work for?

Did you even read my post Elmer? If you dont want to help, dont reply.

Sorry, I didn't read your comment completely. I don't have any personal experience to contribute but I guess my comment applies more broadly to your co-workers. It's odd that you've gotten both evasive and quizzical answers.

Hi, Andrew,

Preventive (PM) and predictive (PdM) maintenance activities need to be cost effective. Many motors in critical, continuous process applications have continuous vibration monitoring systems to avoid failure or at least provide an early warning that permits a controlled shutdown of the process or a switch over to other (e.g., installed spare) equipment. Others might be part of a walk-around vibration monitoring route and others might rely on the hearing of experienced operators who can usually tell if something is wrong by the change in the sound of the equipment. When I worked in the process industry, I found a good lubrication program including oil analysis and periodic IR inspections were the PM and PdM activities that provided the best return on investment.

Those same systems and PM and PdM activities aren't appropriate for a residential HVAC blower motor or a condenser fan motor that costs $100 to $150, is readily available, and where the consequences of a shutdown are a couple of hours of discomfort. It's a throw-away component.

For belt-driven motors in residential HVAC applications, visual inspection, basic sheave alignment and belt tensioning are probably the most appropriate PM activities. If you want to well-- amp up the PM stuff-- the next level would be a quick IR scan of the controls and electricals.

Good luck in the latest chapter in your career. Check back here on houzz.com There are some colorful characters who'll be glad to weigh in on most any topic. HVAC threads attract some of the most entertaining.

Welcome to houzz Andrew. Your conclusion that a standard doesn't exist is exactly right. Precise clearance is important but is established during mfgring and can not be measured in the field so it isn't something to worry about. I have a suspecion you are actually seeing end play in shaft which is normal and shouldn't be a concern either. It's really sad your employer doesn't have a training program or at minimum have new hires working under supervision of someone that know's what I just told you. Good luck with the new job and come to ask questions any time.