The thermostat on a mid efficiency gas furnace with a hot surface ignition system is placed on a call for heat. The burners do not light, but the igniter does glow. Which of the following would be the next step to take when troubleshooting the system?

The draft pressure switch on a mid efficiency furnace is not allowing the ignition system to energize. Which of the following is a possible problem?

A high efficiency gas furnace will not stay in operation. The unit runs for approximately 5 min then is shut down by the main furnace controller with an open pressure switch flash code. Which of the following is not a proper test to perform in this situation?

A service call is made on a mid efficiency furnace. On a call for heat, the induced draft motor will not operate. What is the proper troubleshooting procedure that should be taken?

A high efficiency furnace that uses a furnace controller will not energize the blower motor after a preselected 45s “time on” setting. Which of the following would be the most correct troubleshooting procedure?

When servicing a mid efficiency furnace, the thermostat has been turned to the off position, but the burners remain lit, and the induced draft motor continues to operate. Which of the following would be the most correct troubleshooting procedure?

On a high efficiency furnace that uses a furnace controller, the indoor blower motor will not de energize after it’s preselected “off delay” setting. Which of the following is a logical repair for the system?

The burners on a furnace cycle for approximately 3 to 4 min. during a call for heat, the system does not provide adequate heat for the home. Tech A has determined that a new thermostat has been installed and the heat anticipator was incorrectly adjusted. Tech B cleans and positions the flame sensor and claims this was the fault. Which tech is correct?

A gas furnace has been recently converted to LPG gas on a call for heat, the furnace is not firing correctly and is starting to soot up. What would be the most likely cause for this problem?

When inspecting a gas furnace, it is noticed that the burner flames are very small in height. What action should be taken by the technician?

A customer is experiencing loud, delayed ignitions from his furnace. Tech A says that it’s possible that the gas valve is not opening or closing properly. Tech B claims that it’s possible that after the furnace had been cleaned, the burners were not properly aligned. Which tech is correct?

A customer called in complaining that his indoor blower would not stop running. What is the most possible cause of this problem?

After diagnosing a no heat call, it has been determined that the induced draft motor is not operating. Tech A claims that it is the fault of an induced draft pressure switch. Tech B states that the indoor blower relay module is defective. Which tech is correct?

The burners on a gas fired furnace are continuously lit, and setting the thermostat to the “off” position makes no difference. What is a possible problem for this fault?

A customer complains that she has no heat and that the furnace does nothing at all. She says that it is a mid efficiency furnace with an induced draft motor and spark ignition system. Which of the following would be a likely place to start troubleshooting?

On a hot surface ignition system, the igniter does not glow. What would be the most likely cause of this fault?

On a spark ignition system, the spark is occurring but its pilot will not light. Which of the following would you check?

The thermocouple of a furnace has just been replaced, but the pilot light continues to go out. What test should a tech perform next?

An existing thermocouple has been tested with a millivolt meter and has registered at 13 millivolts. Which of the following would be the correct action to take?

What is an acceptable voltage of a thermocouple?