G3 - Gas Technician Level 3 Appliance Installation and Service Questions and Answers Flashcards

When servicing a gas burner with an intermittent pilot ignition (IPI) system, if the pilot fails to ignite, the technician should first check:

Answer: The spark igniter gap and electrode condition

A worn, fouled, or improperly gapped spark electrode is the most common cause of IPI pilot ignition failure.

What is the purpose of a thermocouple in a standing pilot gas appliance?

Answer: Generate a millivolt signal to hold the gas valve open when the pilot flame is present

A thermocouple converts pilot flame heat into a small millivoltage that energizes the safety gas valve, preventing gas flow if the pilot extinguishes.

During annual service of a gas water heater, a technician notices a yellow-tipping flame. This most likely indicates:

Answer: Insufficient primary air causing incomplete combustion

Yellow-tipping flames indicate incomplete combustion due to insufficient primary air mixing with the gas before burning.

A gas appliance heat exchanger should be inspected annually primarily to detect:

Answer: Cracks or holes that could allow combustion gases to mix with circulated air

Cracks in the heat exchanger allow carbon monoxide from combustion gases to enter the living space, creating a serious health hazard.

When replacing a gas valve on a furnace, the technician must verify the new valve:

Answer: Has the same inlet/outlet pressure ratings and voltage specifications as the original

The replacement gas valve must match the original's pressure ratings, voltage, and BTU capacity to ensure safe and proper operation.

After completing a gas appliance service call, the technician should always:

Answer: Perform a leak test on all disturbed connections using approved leak detection solution

All disturbed gas connections must be leak-tested after service to ensure no gas leaks were introduced during the repair.