Question

A shoe store manager calls to report that the heat is off. This store has an electric heat package unit on the roof. The service technician politely introduces himself and his company to the customer. While maintaining eye contact with the customer, the technician asks for the customer's account of the problem. The service technician should always make customers feel like they are helping to find the solution to the problem. Once all of the customer's questions are answered in everyday language the customer can understand, the technician puts on protective shoe covers and starts to troubleshoot. The technician uses the following checkout procedures to determine the problem. You can follow the procedure using the diagram in Figure 15.36. 1. The store manager says the system worked well until about an hour ago when the store seemed to be get-ting cold. 2. The technician notices that the set point on the room thermostat is 75°F, and the store temperature is 65°F. 3. The service technician now informs the store owner that he has to get onto the roof of the building. Once on the roof, the technician removes the low-voltage control panel. The voltage from C to R is 24 V and the voltage from C to W (the heat terminal) is 0 V. There is a 24-V power supply, but the heat is not operating. 4. The room thermostat is removed from the subbase, and a jumper is applied from R to W. The heating system starts. What is the problem and the recommended solution? What is the problem and the recommended solution?

Answer 1

The primary issue detected by the technician is the lack of voltage transmission from the common (C) to the heat terminal (W), despite a proper 24-V supply from C to the power terminal (R). This absence of voltage at the heat terminal leads to the store temperature being lower than the thermostat setting (65°F < 75°F).

What is the recommended solution?

The recommended solution involves the removal of the room thermostat by the technician and the introduction of a jumper connection. This jumper connection directly bridges R to W, allowing for a direct supply of power to the heat system.

Consequently, this action activates the heating system and provides the necessary power supply, ensuring the shoe store's heating system functions at the required capacity.

See image below for missing part of the question.