Our troubleshooting problem involves a complaint from a customer who is concerned that their 9-year-old electric furnace is running excessively and wasting energy. The customer also tells the dispatcher that the system has never been serviced, and they considered calling last season because they thought that the operation of the unit may not be normal, but they put it off. Now, their description of the situation is that they’ve recently noticed that the problem seems to be worse than it was the year before.
What you find on this service call is that this system is a stand-alone straight heating unit, and the cooling system for the building located in the southwest, is a separate evaporative cooling unit. The temperature is not comfortable in the building and the thermostat is turned to a maximum setting. After confirming that the filter is clean, you note that the indoor blower motor is wired to ORG and RED. As your first step, you note the temperature rise listing on the equipment tag and perform a temperature rise test, which shows a result of lower than called for according to the manufacturer’s specifications.
With your air flow evaluation accomplished, you check the electrical system (see Figure One at the top of the page), and find 240 VAC applied to terminals L and R on each of the four heating element connections. Your subsequent ammeter tests show a current draw within the manufacturer’s specifications on two of the elements, while at the top element (ORG from Circuit Breaker #1) and the bottom element (BLK from Circuit Breaker #2) show 0-Amps.
Your troubleshooting question: What is your next step in servicing this equipment?
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