A typical gas water heater consists of a steel tank, a layer of insulation, and a sheet metal jacket. The bottom of the tank is heated by a fixed gas burner that is controlled by a thermocouple and a regulator valve. To vent excess heat and noxious fumes, a gas heater tank is equipped with a hollow tube, through its center, that connects to a house flue.
Flame Burns Orange
If the flame in your gas water heater burns orange and jumps and pops, the system may not be getting a sufficient supply of secondary air. An orange flame means higher operating costs. Be sure that the heater has a sufficient supply of combustion air by opening doors in confined areas or by installing louvered vents in the doors.
A clogged flue is caused by rust or debris that accumulates at tight bends in the flue pipe. A serious health hazard, a clogged flue may force deadly carbon gases into the living quarters. An easy way to check that the flue is working properly is to place a burning match or burning piece of cardboard near the flue hat while the heater is on. The smoke should be drawn into the flue. To locate an obstruction, turn the heater to pilot and disas¬semble the vent pipes. Inspect and clean each piece of pipe and then reassemble the flue.
Heater Burning Unevenly or Not at All
If your heater is burning unevenly or not burning at all, it may have dirt in the pilot line or burner line. To clean these lines, disconnect them from the regulator and slide a thin wire through each line. Blow air through the lines. If dirt is lodged in the gas control valve, call a plumber. Control valves are delicate mechanisms that can be dangerous if serviced improperly.
Pilot Light Out
If the pilot light on your gas water heater is out or won’t burn, the thermocouple may need to be replaced. The thermocouple is a thick copper wire that has a heat sensor on one end and a plug on the other. Heat from the pilot flame sends a tiny millivolt charge through the wire, which causes the plug to open the control valve. When a thermocouple’s sensor burns out, the heater’s magnetic safety valve remains closed and the pilot light won’t burn. To replace a thermocouple, turn off the gas and disconnect the entire burner assembly from the control valve. Remove the thermocouple from its retainer clip near the pilot and snap in a replacement. Be sure to position the sensor directly in line with the pilot flame. Reconnect the burner assembly to the control valve.
If You Smell Gas
If you smell a strong gas odor, it’s likely there is a dangerous gas leak. Leave the house immediately and call your gas or utility company.
If you smell only a light trace of gas, it may be a leaky pipe joint. To find the leak, brush every joint with a mixture of dish detergent and warm water. Soap bubbles will appear around the leaky joint. Turn off the gas at the meter. Bleed the line at the union located above the heater and ventilate the area. Take apart the leaking joint and clean the fitting and pipe thoroughly with a wire brush. Reassemble the parts with pipe-joint compound. Tighten all the joints. Turn on the gas, bleed the air from the line, and retest all the new joints with soap and water.