AO Smith ProMax Water Heaters

AO Smith ProMax Water heater Overview

The A.O. Smith ProMax is a series of gas and electric water heaters. The electric models all come with a PermaGlas glass lining, a certified T&P valve, and low-watt density copper heating elements. Electric units include tall, short, and lowboy models and range in capacity from 6 to 119 gallons. The gas models feature FVIR Technology, which prevents against accidental ignition of flammable vapors, and range in capacity from 30 to 98 gallons. The ProMax line of water heaters qualifies for most utility and gas utility rebate programs.

ProMax gas units feature several venting options, including Direct Vent, which uses a one pipe dual-channel closed system; the Power Vent Higher EF, designed to deliver a greater energy factor; the Ultra-Low NOx Power Vent, which uses a combination of radiant heat and excess air to reduce emissions; and a Side Loop system available as a Direct Vent, Power Vent, and Power Direct Vent.

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Consumer Reviews of AO Smith ProMax


  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
  • #2 of 4 AO Smith Water heater
  • 33.33% of customers recommended

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AO Smith ProMax Water heater Reviews

Showing 1-5 of 45 reviews

"AO Smith: defective product and refusing to honor warranty"

1.0 rating
Very Unsatisfied

Never again will I buy an AO Smith product. This is a dishonest company if there ever was one. My water heater started leaking from the bottom due to rust after only four years. Clearly a defect unit. Still under its six-year warranty, the company refused to honor the warranty and, instead, tried to buy me out of the warranty for a fraction of the replacement cost. These people are scumbags who do not stand behind their products, do not care about their customers and do not deserve to be in business.


Potomac, MD

"JUNK – Don't buy"

1.0 rating
Very Unsatisfied

Don't buy this piece of junk. Controller went out after three years. Extremely expensive to fix. Avoid AO Smith at all costs.

R.G. Millard

Nisswa, MN

"Performing well."

5.0 rating
Very Satisfied

Installed new in September 2005 and no troubles. Still performing well.

Reg Mryer

Tucson, AZ

"15 Trouble-Free Years"

5.0 rating
Very Satisfied

We had 15 completely trouble-free years from our ao Smith Pro Max (installed myself 2002, 6-year warranty). I think it would have lasted even longer had I headed the instruction to periodically drain some water from the bottom and had I checked the condition of the anode even once. Yesterday the tank started to leak and I happened upon this website while checking possible replacements. I don't doubt the reviews of others, but my experience was a very good one. I wonder if satisfied consumers are less motivated to write reviews than are unhappy consumers.

T Overton

Minneapolis, MN

"Poor Quality heater"

1.0 rating
Very Unsatisfied

Our home warranty company replaced our gas water heater 3.5 years ago with AO Smith heater. It has developed rust bubbles on lower left side of the heater , and dried rust powder in the safety pan under the heater , which indicated a leakage at some point. When I talked to AOS rep, she said they do not replace heaters because of rust. She gave the excuse of high humidity area the unit is kept in. I live in Las Vegas, averages year around 12-15 percent humidity, and the heater is installed in the garage. I do not see the point of arguing about it, they will not do anything to replace their inferior, defective product. All I can do is to advise good citizens to stay away from a o Smith products.

Alex Barton

Las Vegas, NV

Other ProMax Reviews

Based on online comments, it sounds as though professionals and consumers like the ProMax and think that A.O. Smith has a good warranty. Members on several sites ranked the ProMax favorably against other models, although it was not an overwhelming choise. For those with problems, faulty installation appeared to be a common cause. A consumer on had a problem with a ProMax gas water heater, and it turned out to be a combination of a bad pressure switch and faulty installation.

Question and Answer


How do you adjust the water temperature on an A.O. Smith ProMax water heater?


On 2016-01-25 Gary wrote:

The thermostats are located behind the access panels. To adjust the water temperature you have to remove the top and bottom access panels and fold aside the insulation. Turning the thermostats clockwise will increase water temperature while counterclockwise will decrease temperature. Some models may have only one thermostat, located behind the bottom panel. Be sure to turn off electricity to the water heater before adjusting the temperature because of the risk of electric shock.

ProMax Warranty

A.O. Smith provides a 6-year and a 10-year warranty on the ProMax water heater, depending on which model is purchased.


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