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AO Smith Pro Max Direct Vent Water Heater

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You may recognize the name AO Smith from boilers or maybe motors but they are most recognized for are water heaters. They have an extensive line of water heaters; one of their premier models is the ProMax Direct Vent Residential Gas Water Heater. The direct vent design features a single pipe with a two channel closed combustion system. The air comes from the outside rather than the inside. AO Smith Pro Max Direct Vent Water Heater

The outside air works best with the direct vent system because the outside air won’t have the same problems that indoor air does. The best part of the direct vent system is that the air intake is a horizontal intake design. The installation works on all models that are up to 80 inches from the outside wall and there is no electrical use at all. You will save money on that feature right away. The ProMax Direct Vent Water Heater has 4 different models, the gallon capacity ranges from 40 to 75 gallons. The ProMax is a high efficiency water heater that is called the Green Choice Gas Burner.
AO Smith ProMax Direct Vent Water Heater
It is designed with AO Smith’s patented eco-friendly design that includes a reduction up to 33% in NOx emissions. Some other features that contribute to the energy efficient water heater are the Heat Trap Nipples, these nipples come factory installed and they are designed to keep all water in the system as well as protect against any heat loss.

The ProMax System is equipped with a Push Button Piezo Igniter. Unlike other water heater systems that can be annoying to light, the ProMax makes the lighting of the pilot quick and easy. The Push Button system is easy, simply push the button and it will spark up the boiler. No other boiler can make it any easier than that. The AO Smith ProMax is coated with their own coating called Permaglas, not only does this help seal the water heater but it is rust and corrosion proof, thereby prolonging the life of the water heater. The water heater has the company’s DYNACLEAN Diffuser Tip, this works to help stop the amount of sediment that may build up on the water heater over a period of time. Plus it works to help maximize the hot water output.

Before buying this or any water heater, you should read the requirements for installation. Here are just a few of these requirements for the ProMax water heater. You must have a maximum horizontal vent distance of 80 inches from the outside of the exterior wall. You must have at least 30″ of room in order to install the unit. AO Smith recommends a height installation for the heater vent pipe to be 68 inches for the 40-gallon models and 76 inches for the 50 gallon and 75 gallon models. You can read all about the requirements and all other information on the AO Smith website. Do as much research as you can on any water heater that you are thinking of buying. It will be a huge investment and you want to get the most for your money.

20 Comments

  1. After my previous water heater failed after 31 years, I had a 30-gallon A. O. Smith Promax gas water heater installed on October 30, 2007. On November 17, after 19 days, the pilot light went out. For the next seven months, the pilot light continued to fail and had to be relit.
    The pilot failed sometimes every few days, sometimes every day, sometimes four times a day or more.

    Eventually, I had to relight the pilot light every time we needed hot water. The plumber who installed the Promax returned five separate times to try and fix it, without success. An A. O. Smith Authorized Technician tried and also failed to fix it. To help find the problem, I installed a camera at the heater viewing window, and videotaped the pilot failing four times. No one looked at the tapes.

    I began to think that this water heater must be pretty bad if an experienced plumber couldn’t fix it after five tries, and an A. O. Smith Authorized Technician, who works on nothing but A. O. Smith products, also could not get it to work.

    Over seven months, I had to relight the pilot 63 times. At 10-15 minutes per relight (according to A. O. Smith instructions), this comes to a total of between 10-16 hours I spent lighting this heater. I can assure you that having to lay on your stomach at all hours of the day and night, in a cold and dark cellar, is not a pleasant job for an old man.

    A. O. Smith, and the Factory Authorized Service Technician (who is paid by A. O. Smith) blame me for the Promax failure and refuse to refund my money. They say (without any tests or proof) that water vapor coming through the dirt floor in my cellar causes excess humidity which clogs the heater’s flame arrestor, disrupts the air flow to the heater, and puts out the pilot flame.

    In 2003, the Government got into the water heater business. It required all water heater manufacturers to fit a ’flame arrestor’ into water heaters. A flame arrestor prevents the burner flame inside the heater from igniting flammable vapors outside of the heater. All heater manufacturers were allowed to come up with their own design of flame arrestor.

    I learned from some plumbing websites that the real problem with the Promax may not be
    my cellar, but the design of its flame arrestor. All incoming air for the heater’s operation must pass through the flame arrestor. The Promax uses a flame arrestor made from a Corderite ceramic disc. This ceramic disc is about the size of a saucer, so limits the air coming into the heater. In addition, the openings in the disc itself are small, further restricting air flow.

    Aside from any design problem with the Promax, there are several reasons why A. O. Smith blaming me for the Promax failure is nonsense.

    I was given no warning before purchasing the Promax, either from the plumber or A. O. Smith, that humidity was a limiting factor for the operation of this heater. No one told me that this heater needed a certain humidity range in order to work, much less what the humidity range was supposed to be. If I had known beforehand of a potential problem,
    I would not have bought the Promax heater.

    The excess humidity conclusion is not supported by statements in A. O. Smith’s own Instruction Manual (#184165-003) and Service Handbook (#TC-049RC). In these manuals, the word ‘humid’ is mentioned only once in 93 pages, and then only as an indication of tank leakage, not as a cause of pilot flame failure. These manuals are available on A. O. Smith’s website http://www.hotwater.com/lit.html.

    Saying that my cellar is too humid, does not make it so. During December 2008-January 2009, I tested the relative humidity in my cellar using a Honeywell hygrometer. For these two months, the relative humidity was in a range from 51%-65%, staying mostly in the mid-50s.

    A 30%-65% range for occupied areas is recommended by The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE thermal comfort standard for Human Occupancy, Standard 62.1-2004). Their chart can be seen at http://www.ccohs.ca/oshanswers/phys_agents/thermal_comfort.html.

    This means that even though my family doesn’t actually ‘occupy’ our cellar, the relative humidity there is within ASHRAE standards. This normal reading is more significant in that during January 2009 we had four times as much snow (i.e. more moisture thus more humidity) than during the same period in 2008 when the Promax was installed. In other words, during January 2008, the humidity level in my cellar was probably even lower.

    I also tested the wooden beams in my cellar with an Extech moisture meter. All the wood tested normal at 20% or less moisture. My home was built in 1924, so these normal readings are after 85 years of supposedly excess humidity.

    These tests show that my cellar is not ‘too humid’ as A. O. Smith maintains and therefore is not likely to be the cause of their product’s failure.

    My films of the Promax pilot light failure show that the pilot fails in several ways; it goes out by itself, or when the burner tries to go on, or when the burner is lit and then turns off. A. O. Smith’s lack of air explanation for the pilot failure seems suspect considering that the burner itself, which must require thousands of times the air the pilot does, had no trouble staying lit (once the pilot was lit) during a heating cycle.

    The solution for pilot flame outages, A. O. Smith’s Legal Department says, is to clean (vacuum) their ceramic disc flame arrestor top and bottom routinely. To do this the burner must be removed, not a job the average customer can or would want to do.

    Some plumbers state (see links below) that it is impossible to properly clean the bottom of this ceramic disc at all, as that part is nearly inaccessible. In any case, calling a plumber ‘routinely’ (every three months? every month?) is expensive and irritating, considering that your old heater may have lasted for decades without any attention at all.

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    I believe that most people would consider it intolerable if a brand-new car failed to start 63 times in seven months. After experiencing similar inconvenience, not to mention cold water, I replaced the Promax with a Bradford-White heater (my choice and in spite of the plumber‘s objections) on May 24, 2008.

    The Bradford-White has a stainless steel flame arrestor, the full diameter of the heater, and lets in plenty of air. The Bradford-White has now been installed for a much longer time than the Promax, and has worked perfectly in the exact same location, in the exact same ‘humid’ conditions.

    I am out almost $1,000 for A. O. Smith’s measly 30-gallon gas water heater.

    • I have experinced similar problems. I would like to institute a class action law suit and CPSC investigation for AO Smith knowingly marketing a defective and highly dangerous product. Would you be interested in joining. PS I am a lawyer and believe we have a case.

      • We puchased this water heater 3 yrs old. This is the second time in two months that our pilot light went out. The first time we replaced the flame sensor. Do we have to replace again. Once again it is 9:30 at night, so we can”t get any help right now, and we have to work tomorrow…so no hot water for two days? We would like to join your law suit.

  2. Question I recently had a Pro Max power vent installed…the light has been going out. Normally after turning it on and off a few times it will just stay on but recently I have been having problems. I now need to find a person who services AO Smith (since the contractor who was doing the work on my home took off, left us in a huge mess one year later and I do not know the licensed plumber who installed the damm thing) thats another story,,,anyway do I have something to worry about? Are AO SMith water heaters safe? I have five children in this home along with an alzhemired mother in law….What do I do?

    • In days of old I would have instantly said change out a thermocouple.
      Give it a shot and cross your fingers, clean the flame arrestor under the water heater as well.

  3. I just had A Bailey Plumbing here and he is saying the gas value needs to be replaced…He just had the same thing with another customer. Cost $750.00 plus tax,,,,what do I do?

  4. We r having the same problem with our so smith pro max water heater. Having to re light several times a day. I emailed the customer service. No response. Does anyone know a phone number. Also to the lawyer please advise regarding the class action suit. We’ve had it and can’t keep running to the basement for hot water. We got. Brand new tank installed November 2007. Please help!

  5. Having the same problem with AO Smith Pro Max, stays lit some times for days other days have to relight over and over. no regular pattern. replace TC last year and everything was fine for about a year. seem to be seasonal? keeping finding more of the same stories on the web… unacceptable. Installed in new house 4 years old. any help appreciated

  6. HAVING THE SAME PROBLEM WE ARE LAID OFF AND DONT HAVE ANY MONEY TO PAY PEOPLE WHO CANNOT REPAIR THEIR OWN PRODUCT!!! THIS PROMAX HEATER IS ONLY 4 YRS OLD THATS ALL!!! THIS CRAP IS UNACCEPTABLE!!!! THIS COMPANY SHOULD NOT BE ALLOWED TO SELL JUNK!!! WONDER WHY PEOPLE DONT WANT TO BUT AMERICAN!!!

  7. Hi,
    I have a similar problem with a pair of promax WH. the little trouble shooting lights are on indicating a system lock out. If I turn it off and on again the blower will come on then the igniter will glow and finally the flame will light, but will shut off after 3 or so sec. I repeats this pattern 3 times then goes into lock out. Any ideas. they are both less than 3 years old.

  8. We also have the same problem. If there is a lawsuit, I’d be interested in more information. Ours was installed brand new in December 2004. We have five kids and not a lot of money so I just end up restarting the pilot light every time. Has anyone had any luck having the problem fixed?

  9. Same problem on our Promax, The plumber finally punched o hole in the ceramic flame arrestor! if there is a suit, count me in!

  10. Same problem here. I have had the water heater for two years, and now I have to relight it several times a day.

    • Oh forgot to say that the water heater is an A O Smith Promax, 40 gallon. I see reviews similar to this one all over the internet. This is very frustrating.

  11. Hello!
    To all participating in this subject I too have been experiencing the same $%^&* with my ProMax AO Smith water heater for the last year and a half. It started when the pilot began to shut off every 3 months or so until it became a more frequent event up to every day, several time a day. I finally called the plumber that installed it and he called the place where he bought it from and he was told that AO Smith basically said I was screwed because they did not cover it. Long story short this the plmuber cleaned out the bottom plate twice now at $175 a pop for his time. He takes apart the control and gets limited access to the burner area and blasts it with the air can used to clean off keyboards while at the same time sticking the skinny attachment part of the vacum cleaner to collect the dust and other debris that is cloggin up the tine pin needle holes of the plate. Quite frankly this shouldnt have to be!!!
    Thank you!!
    Miguel

  12. Bought a new house with the AO Smith hot water heater. After one year having the same problems. wont stay lit. Just purchased a new thermal coupler unit which took 3 days to get. Installed and same problem

    If there is a law suit I’m in no warrenty thats crazy. How can a company not back their product???

    David

  13. the manuel says to clean the filters once a year/the manufacturers are required to make “explosion proof water heaters”now. I am a plumbing contractor,i knew this would happen when they passed that law,talk to your congressman that passed it,it supposedly disperses gasoline fumes and burns them off or shuts down the burner before it can explode when some genius sets a gas can next to it

  14. just read what hotchkiss wrote/we install alot of bradford whites,they breakdown less often,especiall the new low nox with smart valve version

  15. I’m also having the same problems as everyone else here. If there is a class action law suit count me in. Mine’s only 3.5 years old and I need to restart it every time I need hot water.

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