HVAC manufacturers specify maintenance practices, but few owners follow them. Among those that employ the recommended maintenance practices, there's a tendency to treat suggested schedules as maximums. This can cause unnecessary expense and preventable discomfort to occupants. Some things to consider:

• Perform insulation resistance tests on the blower motors (annually). For two-speed motors, check both sets of windings. When a blower fails in the summer, the condenser may ice up and not thaw for several hours. A winter blower failure may go undetected until the occupants finally complain. By the time you troubleshoot and obtain a replacement, the heat loss may be significant and result in extended indoor cold.
• Use infrared or ultrasound regularly to nearly eliminate "surprise" motor bearing failures. Bearing failures typically result from maintenance failures -- such as improper lubrication and inadequate filter changes.
• Understand that the recommended filter change interval is based on a "typical" application, not necessarily your application. You can inspect filters frequently, or you can automate detection by installing d/p instruments (delta pressure) across the filters.
• When the cooling season has ended, cover condenser units so they don't accumulate winter grime. Schedule time in early spring or late winter to clean and comb the condenser fins.
• Have a qualified person conduct the full battery of heating system inspections, if these inspections were not performed during the summer.

Now with cold weather approaching, the plant manager remarked that maybe the plant should issue gloves and mittens with the company logo to all office personnel -- not a good sign.

The system uses a modern furnace with heat pump, and you can hear the furnace kick in during high demand. Is this really an electrical problem? What should you do?

If your blower motor has been in service for a long time, it's not likely you have a preventable cause of failure. But it is likely that other motors installed at about the same time will fail soon. Have replacements on hand. If there's an accessibility problem or extreme temperatures are forecast, don't wait for failure to happen. Do a post-mortem on the failed motor and then check the remaining motors for signs of a similar failure.