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NORA Oilheat Technicians Manual

Chapter 15—Service Procedures 15-7 a last look around to make sure that the area is clean, that you have taken all your tools, removed all jumpers and returned all controls and thermostats to their proper settings. Give the customer the appropriate copy of the invoice, explain what you did and the efficiency test results and answer any questions they have. Thank them for their business and return to your vehicle to move on to your next call. Helpful hint: try to avoid unplugging any electrical appliances when performing service. If you must unplug anything, ask the customer for permission first and leave your truck keys tied to the cord to ensure you will plug it back in before you leave. Troubleshooting suggestions The following is intended to help you troubleshoot typical problems that you are likely to encounter. It is not a list of all possible situations or each and every step you should take to troubleshoot problems. #1 No heat—the unit is cold and the burner is not operating. If the primary control has no power: 1. Check the limit controls. If the limit control has power coming through it there is a problem with the wiring between the limit and the primary control. NOTE: Make sure you have checked all of the limit controls; for example—on a system with both a high limit aquastat and a low water cut-off, you must make sure that both are allowing electricity to pass through to the primary control. 2. If the limit control has no power coming to it, check the switch. If there is no power to the switch, check the circuit breaker or fuse. 3. If you reset the circuit breaker and the unit runs, do not leave right away because something caused the breaker to trip. Use an ammeter to determine if any of the system components are malfunctioning. If the primary control has the correct input voltage, but no power is going to the burner motor, igniter or oil valve: 1. Check to be sure that there is not a fire in the chamber. (Cad cell primaries will not energize if a fire is sensed.) 2. Make sure that the thermostat is set well above room temperature and the heat anticipator is set to the current draw of the control circuit. 3. If the burner still does not start, disconnect the thermostat wires from the TT terminals of the primary control and install a jumper. If the burner starts, there is a problem with the thermostat or its wiring. 4. If the burner still does not start, disconnect the cad cell leads from the F-F terminals. • If the burner starts, there is a problem with the cad cell or its leads. • If the burner does not start, check to be sure that there is not a piece of wire or something else shorting out the F-F terminals. • If there is nothing shorting out the FF terminals, the control is probably malfunctioning. Use your ohmmeter to perform the test mentioned earlier. If the primary control is passing the correct voltage through to the burner components but: A. Motor runs but no flame 1. Disconnect the nozzle line and check the oil flow. If water is found in the oil, drain it from the tank. 2. If the flow is good and water free, check the nozzle and ignition system (see next section B, on following page.) Chapter 15 Service Procedures


NORA Oilheat Technicians Manual
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