Water Heater Troubleshooting
Standard gas and electric water heaters use an insulated storage tank. Water heaters are generally very reliable but on
occasion, they do have problems. Below are the most typical problems experienced.
Before working on any water heater, make sure to take the following safety measures:
• Turn off power to an electric water heater. Do this by turning off the circuit breaker or fuse powering the heater.
• Turn gas pilot control valve to "pilot" setting.
• Shut off water supply to water heater.
Problem: No Hot Water
Possible causes could be a faulty gas pilot, gas thermocouple, gas pilot control valve, electric thermostat or upper electric
heating element.
Try This:
• Check gas pilot flame and pilot operation
• Re-tighten, reposition or replace the gas thermocouple
• Replace the gas pilot control valve
• Confirm power is being provided to the electric water heater thermostat
• If power is being provided to electric thermostat, replace thermostat or heating element
Problem: Inadequate Hot Water
Possible causes could be that the unit is undersized for water heating demands, a broken or damaged dip tube allowing
cold and hot water to mix in tank, a faulty plumbing installation has crossed cold and hot water connections, gas supply or
control issues or a faulty electric lower or upper heating element or high or low heating element thermostat. A constant
supply of lukewarm water during a shower is indicative of a defective upper heating element. Short duration hot water
supply during a shower is indicative of a defective lower heating element.
Try This:
• Make sure water heater is not being overtaxed by hot water supply demands. The water heater should have 75%
of its capacity as hot water (e.g., a 40 gallon water heater should be used for a demand of 30 gallons).
• Undo cold water inlet and pipe nipple and remove dip tube. Check condition and replace if required.
• Check for crossed connection by turning off water supply to water heater. Open hot water tap at a faucet. If there
is water flow, then a cross connection exists somewhere. Check for a hot water line connected to a cold water
connection on the water heater or appliances such as washer, dishwasher, faucet or shower valves.
• Check for proper flame from burner. A natural gas flame should be a bright blue with the tip of the flame having
just a tinge of yellow. A propane flame should have a bluish green flame with a tinge of yellow at the tip.
• Check for power and electrical continuity at the lower and upper heating elements. Replace water heating
element if necessary. Clear tank of any sediment first.
• If elements test OK, check for power at upper electrical upper thermostat. If OK check lower thermostat. Replace
if necessary.
Problem: Rust-Colored Water
Possible causes could be corrosion occurring inside glass lined tank or the sacrificial anode rod is failing (anode rods
dissolve slowly to prevent rusting in the tank).
Try this:
• Replace sacrificial anode rod with magnesium anode rod.
Problem: Rotten Odor
A possible cause could be bacteria in the tank sediment fed from hydrogen gas created from decay of sacrificial anode.
Try This:
• Flush water heater.
• Using a hydrogen peroxide solution of two pints (3% peroxide to 40 gallons of water) treat tank and run some of
the solution into water lines.
• Let peroxide solution set in tank and pipes for two hours. Solution is not toxic and requires no rinsing.
• If problem persists, replace anode with a zinc-alloy anode.
• If problem still remains, replace water heater with a plastic lined tank type.
Problem: Low Rumbling Noise
A possible cause could be an excessive buildup of sediment in bottom of tank is causing the tank bottom to overheat and
boiling of water to occur.
Try This:
•
Remove sediment by flushing water heater.
Problem: High Pitched Whining (Electric Heater)
A possible cause could be a buildup of scale material on electrical heating elements.
Try This:
• Flush water heater.
• Clean scale from water heater tank and elements.
• Install low-watt density heating elements that have larger surface area to transfer heat to water more efficiently
and conduct less electrical wattage per square inch than a standard high-wattage element.
Problem: Leaking Water Around Base of Heater
Possible causes could be a faulty T&P (temperature and pressure) relief valve, a T&P valve leak due to excessive
pressure or overheating or a leak from overhead or nearby plumbing connection or a leaking water tank due to corrosion.
Try This:
• Place a bucket under the overflow pipe. Open and flush T&P valve clear of debris. If leak remains from valve,
replace valve.
• Reduce thermostat setting to prevent tank overheating and opening T&P relief valve.
• Inspect bottom of tank by looking through combustion chamber. If water marks or heavy rusting is noticed, or if
water is noticed setting in combustion chamber bottom, then the water heater needs to be replaced.