Water Heater Troubleshooting FAQ & Flood Tips - HD Supply

Quickly troubleshoot some common hot water heater issues, and also get tips on flood control and recovery.

Why did the red reset button on my electric water heater thermostat "trip"?

If the red button trips or snaps, the temperature of the water is higher than the safety cut off setting. Allow water temperature to drop. The safety cut off limit can be reset when the water temperature is 120°F or below.

Why does my temperature & pressure relief valve keep popping out?

The temperature & pressure relief valve is a safety function which will releases water (and thus pressure) if the temperature or pressure in the tank gets too high.

Many newer housing developments have water meters with check valves or backflow prevention valves. Some building codes require them so that once water enters your property, it can't go back into the water supply system. When the water in the tank is heated, it expands, making more volume and more pressure. Without a backflow prevention valve, the water could get pushed back out to the main supply. In a newer system the backflow valve prevents this, and pressure builds in the tank until the relief valve activates and releases water.

To address this, contractors are installing water pressure reducing valves along with expansion tanks. Both of these items can address thermal expansion caused leaks of the T&P valve.

Why does my pilot light keep going out?

Sometimes wind simply blows out the pilot light. Be sure all covers are in place. Check the manual reset thermal switch, venting, air supply, gas valve magnet, gas pressure, and also check for dirt in the pilot orifice.

What is the Energy Factor of my water heater?

The water heater Energy Factor (EF) is a measure of the overall efficiency of the water heater. This is determined by comparing the amount of energy required to heat the water used daily as well as any "standby" loss of the hot water. The higher the EF, the lower the annual operating costs.

Where is the anode rod on my water heater?

For most water heaters, the anode rod located inside a threaded "spud" connection on the top of the water heater. Anode rods can either be attached to the hot water outlet nipple fitting or in its own dedicated anode "spud". Often the location is clearly marked "anode."

Why is my flame yellow?

The pilot flame should be mostly blue. If it is mostly yellow the combustion system may require adjustment or servicing.

Can I put an insulation blanket on my water heater?

Most new water heaters use a new higher "R-Value" foam-type insulation and do not require additional insulation blankets.

Before recent government NAECA (National Energy Efficiency Conservation Act) updates, many older water heaters did not contain as much tank insulation. For that reason water heater insulation blankets were installed from time to time. Therefore, blankets for older fiberglass insulated water heaters might make sense. As with any appliance, please refer to the manufacturer's installation instructions and follow their guidance. Never cover any air openings, warning labels, or safety devices if using a blanket.

How often are you supposed to flush a water heater?

Most manufacturers recommend you flush your hot water tank once every 6 to 12 months. If your local water is harder or contains more minerals, you may need to do so more frequently. At a minimum, drain two gallons of water from the drain valve every other month.

Why does my water smell?

Most likely the smell is related to hydrogen sulfide. There are three common ingredients required to generate the hydrogen sulfide odor that gives water its rotten egg smell: sulfur, hydrogen, and bacteria.

It may be possible to replace the anode rod that protects the surface of the tank with a special alloy anode rod that will reduce hydrogen creation and lower the potential for odor. It is never recommended to permanently remove the anode; this will void the warranty and shorten the tank's life.

The best way to control odor is by reducing bacteria that is present in the tank. Sulfur eating bacteria is resistant to high water temperatures, so the best way to combat it is through sanitation.

How do I chlorinate a water heater to remove the bad smell?

  • Turn off the water and power supply or gas supply to the water heater.
  • Drain several gallons of water from the drain valve on the water heater.
  • Remove the hot water pipe nipple.
  • Pour 1/2 to 1 gallon of chlorine bleach into the water heater through the hot water outlet opening.
  • Reconnect the hot water supply line to the hot water outlet on the water heater.
  • Turn on water supply and run water at each hot water faucet until a chlorine odor is noticed.
  • Once the chlorine odor is noticed, turn off the faucets and allow the bleach to sit in the water heater and water lines for a minimum of three hours, but a full day is desired.
  • Turn on water at each hot water faucet in the residence until a chlorine odor is no longer present.
  • Turn on the power or gas supply to the water heater.

Why do I run out of hot water?

Either your hot water demand greater than your system can handle or the system is not properly providing its maximum hot water supply.

If the demand for hot water is too great there are several options to deliver greater amounts of hot water, such as a condensing high-efficiency tank type water heater, a large flow-rate tankless water heater, or possibly a large capacity hybrid electric heat pump water heater.

To determine whether or not a water heater is operating properly, you will have to run a test, using standard mercury thermometer and standard 3 or 5 gallon buckets.

Once the water heater has completed its heating or recovery cycle, draw all the hot water at approximately 3 gallons a minute and the measure the temperature.

Note the number of buckets of water to reach a point 30 degrees lower than the highest temperature. Multiply the number of buckets by 3 (or 5 if using a 5 gallon bucket).This figure should then equal, or exceed, 70% of the rated capacity of the heater.

If 70% of your volume capacity is efficiently drawn off and operating recovery time is normal, then it can only be concluded that your demands are greater than the water heater's delivery ability.

Why is my water heater making noise?

The two conditions that may cause tank noise are water hammer and mineral build-up.

Water Hammer - When water is flowing through a pipe and is stopped abruptly by quick-closing valves, such as solenoid valves on clothes washers and dishwashers, water hammer results. Single lever faucets can also create these "shock waves". Piping, water meters, storage tanks, water heaters, temperature and pressure relief valves, and pressure regulator gauges can be damaged. Water hammer can be can be controlled by installation of water hammer arrestors, expansion tanks, or pressure-only relief valves in cold water make-up lines at 25 to 50 pounds less than the temperature and pressure relief valve setting on the water heater.

Mineral Build-up - Lime formations or sediment collecting on the tank bottom or on electrical elements can cause water heater noises. It is not uncommon to find quantities of sand and other minerals settling out of the water and onto the tank bottom. Hand cleaning parts by scrubbing with a vinegar solution may help to reduce build-up. Flushing the tank could also fix the issue. In some hard water areas, installing a water softener, to inhibit scale build-up may also help.

Flood FAQ

If my water heater was in a flood, do I need to replace it?

Yes. Any water heater that has been in a flood— gas or electric, commercial, or residential—should be replaced, not repaired.

After being in flood waters, valves, controls, and thermostats will start to corrode. The unit's insulation will have absorbed contaminated water and will be nearly impossible to disinfect or dry out. The tank itself will begin to corrode from the outside.

When installing the new water heater unit do not reuse the temperature and pressure relief valve if it was in flood water. Replace it with a new one. Also, remember to check that the gas supply line is clear of water or dirt, usually this is done at the lowest point in the gas distribution system prior to gas burning appliances. Get more tips on flood recovery.