Checklist: Water Heater Preventive Maintenance
Your customers have at least one thing in common: They don’t want their water heater to break down. As a trade professional, you’re likely aware of the facts about how to maintain a water heater and prevent system failures, including that:
Regular maintenance can preserve water heater efficiency and extend lifespan as long as it’s performed routinely from the time of installation.
Flushing the tank of a poorly maintained, old water heater can sometimes do more harm than good.
This presents an opportunity for plumbers, HVAC specialists, and commercial contractors when installing a new residential or commercial tank water heater. Annual or biannual HVAC service contracts are an excellent way to grow your business and better serve your customers. To help you start the discussion, learn how routine HVAC service saves your customers money.
Pro tip: Because gas-fired water heaters have significantly more parts compared to electric water heaters, the amount of time required to service gas-fired units can also be greater. Be sure to build this difference in labor into your service agreements.
By explaining to your customers that investing in water heater preventive maintenance can save them from the headache and expense of a breakdown, you’re providing a value-added service that can boost your bottom line.
Learn how regular maintenance can extend the life of your customers’ water heaters, and get step-by-step instructions for performing maintenance checks while flushing the water heater for sediment and bacteria.
Why is water heater maintenance necessary?
Over time, minerals in the water supply wear out a unit’s components, causing damage that can’t be reversed by a sediment flush. This is why water heater preventive maintenance should start in the first year of installation.
At minimum, preventive maintenance on a water heater should be completed once a year, although twice a year is best practice. If your customer is in an area with hard water, recommend more frequent checks to extend the water heater’s working life, as extra minerals may build up at the bottom of the tank.
In addition, parts that help keep the water heater efficient can wear out over time, potentially damaging the unit and the building while increasing utility bills.
Scheduled maintenance gives you the opportunity to inspect and replace parts, allowing you to extend a water heater’s lifespan, sometimes by years.
Here are a few examples of how regular water heater maintenance checks can prevent your customers from experiencing major failures:
An anode rod can degrade too much to protect the tank from corrosion and eventual rust.
A failing expansion tank might just cause a few minor fixture leaks—or trigger the dishwasher or washing machine hose to burst.
A disintegrating dip tube affects hot water availability throughout the building while clogging tank components and water lines with thick particles.
From your own experience on the job, you can probably list even more cases where delayed maintenance created much bigger problems down the line.
For your yearly or biannual service call, using the time you’re spending to flush the water heater of sediment and bacteria is an excellent way to check components in the entire unit. We’ve created a step-by-step water heater maintenance checklist you can follow below or download today to flush the unit and inspect or replace critical components at the same time.
Before you start your scheduled water heater maintenance visits, first double-check that your customer hasn’t noticed any signs of failure, such as cold or discolored water, knocking sounds, or poor water pressure. You might check a faucet or two for yourself to assess temperature and flow before heading to the water heater.
Checklist: water heater preventive maintenance and flushing
Before starting, shut off power or gas: Turn off the breaker on electric water heaters or shut off the gas supply on gas units.
Visually inspect unit for leaks, rust, and corrosion.
Inspect power supply connections and/or gas supply line and shutoff valve.
Check drain pan for signs of water or corrosion.
Open the temperature and relief (T&P) valve, ensure water flows unobstructed from the overflow pipe, and then fully close it.
If equipped, press the valve on the expansion tank and ensure no water comes out.
Examine thermostat(s) and heating elements, as well as thermal cutoff switch, if available.
On gas water heaters, inspect flue baffle and draft diverter or power vent.
Cool water in tank by opening hot water faucets until water runs cold.
Close the cold water inlet valve.
Close all but one hot water faucet so a vacuum doesn’t form.
Connect a transfer pump and hose to the drain valve.
Allow water to flow outside or to a floor drain with a strainer.
Open cold water inlet valve to begin flush, breaking up sediment.
Flush several times until water is clear.
Close the cold water inlet valve again.
Inspect the anode rod and dip tube for signs of disintegration.
Remove the anode rod.
Close the drain valve.
At the anode opening, add one gallon of bleach for every 25 gallons of tank capacity.
Replace the anode rode.
Open the cold water inlet valve to fill the tank.
Open all hot water fixtures, including running dishwashers and washing machines.
Once you’ve detected chlorine at all fixtures, leave system undisturbed for one hour.
Close all but one faucet, drain the tank again, and allow it to refill.
After 15 minutes, open all fixtures again to flush the chlorine from the system.
Continue until you can no longer detect a chlorine smell at any fixture.
Refill the unit and restart per manufacturer recommendations.
As the unit starts, ensure smooth function of pilot light, thermocouple, and burner control assembly on gas water heaters.
Check flammable vapor sensor on gas water heaters, if installed, for error codes and clean if needed.
Heating elements and thermostats in an electric water heater
If your customer tells you they’re not getting hot water at all or for just a few minutes before it switches to cold water, a failing thermostat or heating element in the electric water heater could be the problem. Many residential electric water heaters have a top and bottom heating element, each with its own thermostat.
How to test a water heater heating element
Heating elements can corrode and cause circuit breakers to blow, but you can test them well before they’re visibly damaged. With power supply and/or gas supply completely cut off—and double-checking that no voltage is present—use a multimeter set to ohms and measure the electrical resistance between the screw on each element and three different points: screw, element, and tank body.
The measurement you want to see depends on wattage and voltage, but for most water heaters the range is between 10 and 16 ohms, with 13 ohms right in the middle. If the measurement is very low or zero, you’ll need to replace the heating element.
How to replace a heating element in a water heater
It’s best to do this after flushing for sediment and bacteria so the tank is already empty, clean, and prepped for a new part. With power still shut off, label and remove all the wires. Unscrew the dead heating element and screw in the replacement heating element, ensuring threads are still good. Reconnect the wires and fill the tank completely before restarting.
How to test a water heater thermostat
If the heating elements are good, it’s likely one or both thermostats are bad. To test a thermostat in an electric water heater, first check if the unit just needs a reset from a prior overheating. Then label and disconnect the wires to make sure you’ll be measuring ohms only for the thermostat.
Measure the ohms first with the thermostat set to its highest temperature and then at its lowest temperature setting. Anything other than close to zero, even no reading at all, means you’ll need to replace the thermostat.
How to replace a water heater thermostat
Maneuver the bracket or remove the mounting clip to take out the malfunctioning thermostat. Lock the new thermostat into place either with the bracket or mounting clip, and reconnect the wires you labeled. Fill the water heater and turn the power back on. Wait for the unit to get to full heat before testing a hot water faucet.
FAQs about water heater maintenance
Get answers to other common questions about preventive water heater maintenance, replacing parts, and more.
Q. How do I clean a water heater burner?
A. Use a gentle brush and small vacuum to carefully clear any debris or dust from the gas burner.
Q. How often should a water heater be flushed in hard water vs. soft water regions?
A. Best practice is to flush a water heater twice a year, ideally in the spring and fall as part of your service contract. If your customer has hard water, stick to flushing every six months. If they have soft water, they could extend that to once a year.
Q. Can flushing an older or neglected water heater cause leaks or component failure?
A. Flushing a neglected water heater can reveal leaks and failures, not necessarily cause them. When water heaters haven’t been well-maintained or flushed over a number of years, minerals can build up to the point that the sediment settles into a sort of seal. It could also be caked around pipe, preventing full water pressure from damaging older parts. In these cases, flushing makes leaks and failures more obvious, but the need for a replacement water heater existed before the sediment flush.
Q. What’s the difference between a sediment flush and a bacteria/disinfection flush, and when should each be done?
A. A sediment flush breaks up and removes minerals in the tank, and this should be done every six months. A bacteria flush uses bleach or other approved cleaning solutions to disinfect tanks that may have bacteria, which could be harmless or more dangerous like Legionella and E. coli.
Because it’s a simple extra step after a sediment flush, you can complete this every six months as well. If you or your customer notices that the hot water in their home has a bad smell, a bacteria flush will usually clear that up.
Q. How often should anode rods be inspected or replaced for optimal tank life?
A. If you’re flushing your customer’s water heaters every six months or a year, you’ll have the opportunity to inspect the anode rod every time. Make sure to check it within two years of installing the water heater and, once you’ve had to replace it, check it every year or two thereafter. Because the rod plays a large role in protecting the tank from corrosion, it’s better to replace it slightly earlier rather than too late. The lifespan of an anode rod depends on the material it’s made of and the area’s water quality.
Q. How should expansion tanks be tested during annual service?
A. Check the expansion tank’s PSI to make sure it matches the system’s water pressure. Next, look for any water or air leaks and tighten valves as needed.
Q. What’s the ideal water temperature setting to balance efficiency, performance, and code compliance?
A. States vary in their codes for minimum and maximum water heater temperatures, which themselves might differ from standards for the temperature of water that actually flows from a faucet.
Water heater temperatures set to store water at 140°F can be the right fit for a lot of households—it’s above the 122��F needed to lower risk of Legionella and the high temperatures that are best for some dishwashers and washing machines. But water flowing that hot directly from a faucet can cause scalding, a bigger risk for households with young children.
In these cases, as well as to save on energy bills, many choose to set the water heater temperature at 120°F. For a balance between preventing bacteria growth with higher temperatures and protecting skin with lower temperatures at the fixture, installing a tank booster and/or a mixing valve can be the best solution.
Ferguson can help with water heater maintenance, repair, and replacement
Your checklist for how to maintain a hot water heater can help demonstrate the value of your services to your satisfied customers. Ferguson has all of the water heater maintenance equipment you need to help your customers extend the life of their water heater.
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