How A Water Heater Works

Most problems with water heaters are announced by noises or by water that's either too hot or not hot enough. Often you can correct the problem yourself. A possible exception is a water leak, which may require professional service or tank replacement. Gas leaks call for immediate help from the utility company.

Whenever someone turns on a hot water faucet, heated water is drawn from the top of the tank and is replaced by cold water that is carried to the bottom through the dip tube. When the water temperature drops, a thermostat activates the heat source (a burner in a gas model -- two heating elements is an electric.) A gas heater has a flue running up the center and out the top to vent deadly gasses. An electric heater needs no venting. In both, an anti-corrosion anode attracts corrosion that would otherwise attack the tank's walls.

Maintenance For Good, Safe Service

1. Open the drain valve at the bottom about every 6 months, letting the water run into a bucket until it looks clear (usually about 5 gallons). This will prevent sediment accumulation.

2.Annually test the temperature-pressure relief pressure buildup by lifting or depressing its handle and draining water from the overflow pipe. If water doesn't drain out, shut off water to the heater, open a hot water faucet somewhere in the house, and replace the valve.

Water Heater Safety Tip

If steam or boiling water ever comes out of the valve or the hot water faucets, shut the heater off at once. If you ever hear a rumbling sound, assume the heater is overheating and turn it off.

Water Temperature

If temperature is a problem on a gas heater, check that the temperature control is on and is set correctly (normally 160°- a little lower if there's no dishwasher). If you suspect a faulty control, test it by opening a hot water faucet for 3 minutes. If the heater doesn't turn on, reset the control to a lower temperature and test again. If it still fails, have it replaced.

Draining and Flushing the Tank

1. Turn off the gas or electricity.
2. Close the cold water valve.
3. Attach a hose to the drain valve, to route water into a floor drain or outdoors.
4. Open the drain valve and open one hot water faucet somewhere in the house to let in air.
5. When all water has drained, turn the cold water valve on and off until the water from the drain looks clear.
6. Close the drain valve and the hot water faucet, open the cold water valve and restore power.

Troubleshooting Gas Water Heaters

Knowing how to light the pilot is one key to living with a gas water heater; see the instructions on the tank. For safety, a gas heater has a thermocouple. This is thermoelectric device that impinges on the pilot flame and shuts off the gas if the pilot light goes out. The gas flame should be blue. If it's orange, adjust the shutter; if it's still orange, call for service.
Twice a year, inspect the flue assembly to be sure it's properly aligned and all its joints are sealed. Then check the flue by placing your hand near the draft diverter (with the burner on); air flowing out indicates an obstruction that should be removed. Every year or two, shut off the gas, remove the access panel, and clean the burner ports, using stiff wire or a needle. If you ever smell gas, get out of the house immediately and call the gas company.
There is no hot water.

Check for:
· Unlit pilot light.
· Pilot light won't keep burning.
· Clogged burner
· Defective thermocouple.
· The gas is not coming out.
Remedies:
· Carefully relight the pilot.
· Make sure the gas controls are completely turned on. Then check the thermocouple and be sure it is firmly connected to the gas control unit and positioned near the pilot flame.
· Call a qualified contractor.
· Replace the thermocouple.
· Call the Gas Company.

There isn't enough hot water.

Check for:
· Incorrectly set thermostat.
· Defective thermostat.
· Exposed hot water pipes
· Too small of a water tank
· Clogged burner.
· Sediment has formed in the tank.
· Leaking hot water faucets.
Remedies:
· Turn the thermostat higher.
· Call a qualified contractor.
· Insulate the hot water pipes.
· Install a larger water tank.
· Call a qualified contractor.
· Turn off the gas and drain the tank.
· Repair or replace the faucets.

The water heater is very noisy.

Check for:
· Scale and sediments in the tank.
Remedy:
· Turn off the gas and drain the tank.
The water is too hot.

Check for:
· Wrong setting on thermostat.
· Defective thermostat.
· Blocked exhaust vent.
Remedies:
· Reset the thermostat.
· Call a qualified contractor.
· Check the vent and clear it.

Water is leaking from the heater.

Check for:
· Leak in the draincock.
· Leaking safety valve.
· Hole in the tank.
· Leak in the plumbing connection.
Remedies:
· Close it tightly or replace it.
· Check the water temperature. If it's too hot, the thermostat may be broken. If the safety valve is defective, replace it.
· Buy a new water heater.
· Call a plumber.

Troubleshooting Electric Water Heaters

When an electric heater has problems, suspect the heating elements, their thermostats, and the high-temperature cutoff. The two heating elements (upper and lower), immersed in water, are controlled by thermostats which, along with the high-temperature cutoff, are concealed behind a panel on the side (insulation must be cut away for access after removing the panel). If the high-temperature cutoff has tripped due to water that's too hot, the solution may be as easy as pushing the reset button. High voltage and inaccessibility warrant a service call to adjust the thermostats, reset the high-temperature cutoff, or to replace any of these components of the heating elements themselves.

There is no hot water.

Check for:
· The heater has no power.
· The safety thermostat has quit working.
· Defective heating thermostat.
· Defective heating elements.
· Accumulation of rust, scale, or sediment in the tank or pipes.
Remedies:
· Check the fuse box/ circuit breaker.
· If the heater repeatedly blows fuses call an electrician.
· Push the reset button.
· Test the heating thermostats and elements.
· Test the thermostats and replace if necessary.
· Test the elements and replace if necessary.
· Drain and flush the tank and pipes.

The hot water supply is too low.

Check for:
· Thermostat is set wrong.
· The tank is too small.
· Heat is getting loose in the pipes.
· Defective heating element.
· Leaking hot water faucets.
Remedies:
· Turn the thermostat to a higher temperature.
· Install a larger heater.
· Move the heater nearer to the point of use if possible.
· Insulate the hot water pipes.
· Test the element then replace it.
· Repair or replace the faucets.

The water temperature is too high.

Check for:
· Thermostat is on the wrong setting.
· Inadequate insulation around the thermostats.
Remedies:
· Turn up the thermostat.
· Add insulation around the thermostats.
· Test the thermostat and replace if necessary.

There is a water leak.

Check for:
· Defective gasket or seal on the element.
· Defective safety valve.
· The tank is rusted through.
· Leaking plumbing connections.
Remedies:
· Check and replace gasket or seal.
· Check and replace the safety valve.
· Buy a new water heater.
· Call a qualified contractor.

The heater becomes unusually noisy.

Check for:
· Accumulation of rust, scale or sediment in the tank.
· Scale has formed on the elements.
Remedies:
· Drain the tank and flush it out.
· Remove the elements, soak with vinegar and then scrape off the scale.

Your hot water pipe is rusty or discolored.

Check for:
· Accumulation of rust or sediment in the tank.
· Scale has formed on the elements.
· Corroded water pipe.
Remedies:
· Drain the tank.
· Remove the elements, soak them in vinegar and then scrape off the scale.
· Have a plumber replace the pipes.