Your questions answered: HVAC FAQs. Farnell Mechanical, Inc. in Opelika can answer all your HVAC-related questions. Before you get on the phone, browse these to see if we already responded to your question online. If you don’t see your question in this list or want more information on a topic, give us a call at 334-524-2458. Our staff can provide the information you’re looking for in no time.