Gas Water Heater Trouble Shooting Guide, Repair and Maintenance

Gas water heater trouble shooting guide with repair and water heater maintenance procedures and advice including pilot light, anode, thermostat, dip tube etc.

Gas Water Heater Trouble Shooting Guide and Repair and Maintenance

Trouble Shooting Guide

Do not attempt to trouble shoot or repair your water heater unless you are a qualified technician.

This gas water heater trouble shooting guide assumes that the water heater was properly installed and was operating correctly before any problems developed. This guide is not meant to be a comprehensive trouble shooting document, just a general guide to common water heating problems.

Before trouble shooting your gas water heater check for the odor of gas.  If you smell gas call your gas supplier immediately and have them check for leaks.
 

Problem: No hot water.

Remove the inner and outer burner access covers and Check to see if the pilot light is lit.


If pilot light is not lit.

Attempt to re-light pilot light following the instructions posted on your water heater.

If the pilot light will not re-light, the problem could be a clogged pilot line, or gas is not reaching the water heater. Check with your gas supplier.

If the pilot light will light but does not stay lit when the gas valve control is released the problem could be a defective thermocouple or perhaps a loose thermocouple connection to the gas control valve. Make sure the thermocouple connection to the control valve is tight.


If pilot light is lit.

Turn on a hot water tap and let the water run for several minutes.  Check to see if burner comes on.  If not run the hot water several more minutes. If the burner still does not come on the problem could be a defective control valve / thermostat. Check to see if the control valve knob is  in the "on" setting and not set to the "pilot" position.
 

Problem: Insufficient hot water.

Check the thermostat setting, it may be set too low.  Check for leaking faucets. Check the dip tube, if the dip tube has broken or fallen off, incoming cold water will be drawn out through the hot water outlet without being heated.

Other possible causes are clogged burners and low gas pressure and are beyond the scope of this water heater trouble shooting guide.
 

Problem: Slow hot water recovery.

Sediment buildup in bottom of heater, flushing the water heater may help. Other possible causes may be insufficient combustion air caused by insufficient ventilation, or improper burner operation.
 

Problem: Gas water heater has discharge from TP/relief valve.

The relief valve will operate if either the water temperature is to high or if the pressure in the gas water heater gets too high.  If the inlet to the water heater is fed directly from the water main with no pressure relief valves or check valves between them then when the water heater heats the water and it expands, the extra volume of water simply flows back toward the water main.  If however there is a blockage such as a check valve or pressure reducing valve with a defective bypass then the increase in water volume has no where to go and the pressure with increase dramatically.  Placing an expansion tank in the line at the inlet to the hot water heater will give the increased volume of water someplace to go and prevent operation of the relief valve.

Another possibility is that the City water pressure has increased above the setting of the relief valve. Again the installation of an expansion tank will solve the problem.

Problem: Pilot light won't stay lit.

Sometimes a draft will blow the pilot light out. Make sure the burner access covers are in place. Other possible causes are dirt in the gas line, loose thermocouple connections,  or a defective thermocouple.
 

Problem: Popping or banging noise.

Scale can build up  in the bottom of the tank causing all sorts of noises to occur while the gas hot water heater is heating water. Try flushing the tank.
 

Problem: Stinky hot water.

Certain types of bacteria can react with the magnesium anode rod resulting in a rotten egg odor. Clean the tank using chlorine bleach or changing the anode rod to aluminum usually will solve the problem.

Problem: Leaking tank.  

Replace the water heater. This is beyond the scope of this gas water heater trouble shooting guide.

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