Water Heater Air Intake Screen?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by socalgeo, Mar 13, 2008.

  1. socalgeo

    socalgeo New Member

    Mar 13, 2008
    Hi everybody. Just wondering if somebody could help with what I'm guessing might be a fairly simple question. The pilot light has been going out fairly regularly on my water heater (A.O. Smith, ProMax). I get it to light right back up again, but it's annoying nonetheless.

    Anyhow, a notice on the water heater tells me that the "air intake screen" should be cleaned every six months. I'm not sure, but I'm wondering if this might be related to the pilot light going out on my water heater. Problem is, I have no idea where the air intake screen is to clean it.

    Would anyone out there possibly know? Any help would be much appreciated. If there's another theory as to why the pilot light keeps going out, I'd sure appreciate hearing that, too.

  2. krow

    krow Plumber

    Feb 11, 2008
    Ontario, Canada
    You may see it outside of the house with a rodent gaurd on it. The same place the exhaust is going out. Which one does it look like?

    Attached Files:

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  4. socalgeo

    socalgeo New Member

    Mar 13, 2008
    Thanks. I think it's the second from the left.
  5. krow

    krow Plumber

    Feb 11, 2008
    Ontario, Canada
    Its always a good idea to check your thermocouple. They can do some strange things when starting to burn out.
  6. socalgeo

    socalgeo New Member

    Mar 13, 2008
    Thanks a lot. I see where the vent comes out through the roof, too. I'll definitely give that a look in the morning.
  7. Cass

    Cass Plumber

    Nov 12, 2005
    The air intake will be on the heater its self if it is a standard vent heater and not a power vent, sounds like it is if the vent is on the roof.

    Look and see if there is a plastic screen below the burner area near the floor, if yes remove it and the air intake is in there.
    Last edited: Mar 14, 2008
  8. jimbo

    jimbo Plumber

    Aug 31, 2004
    San Diego, CA

    This lawsuit involved Whirlpool Brand sold at Lowes. However, they are made by American Craftmaster, division of A.O. Smith. Some of the issues may be similar. Contact A.O. Smith or the installing contractor. You need the maintenance manual, and I would like to see more specific instructions than just "clean the screen".

    You might be able to get the maintenance manual for you model online at the A.O. Smith website.
  9. socalgeo

    socalgeo New Member

    Mar 13, 2008
    Thanks for the great input, everybody. I'm gonna check everything out today. Much appreciated!
  10. Redwood

    Redwood Master Plumber

    Dec 15, 2007
    Service Plumber
    They are IMO powerfully close to being a whirlpool water heater....

    MASTERPLUMB777 In the Trades

    Aug 6, 2007
    Retired Master Plumber
    A. O. Smith

    The A. O. Smith Web Site Is Hotwater.com
    Their Tech. Support Ph. # 800-527-1953

    Macplumb 777

    Masterplumber & Master Drainman

    Ph. D. Water Heaterolgy :d
  12. Master Plumber Mark

    Master Plumber Mark Master Plumber

    Feb 6, 2005
    Sensitivity trainer.. plumber of mens souls
    indianapolis indiana - land of the free, home of

    I agree with REDWOOD...thay are real close to a whhirlpool

    if it is a newer than o3 heater ....they are talking about
    the air intake screen under the heater.............
    look at this pic...

    you need an air compressor and an air hose to blow out the lint
    you need to blow it out from underneath the unit and from inslde the chamber

    like the first pic shows lint

    .[​IMG] [​IMG] [​IMG]

    look at the dirt and scale that falls down on that inner air screen.....
    and this heater is only 1 year old..

    Smiths are bascally a pretty crappy heater all in all..

    they have about the same stupid design as the shitty whirlpool---
    but they do use a better gas valve and thermo couplings.

    IHMO ..the better quality parts are the only
    reason they have not had a law suit fiasco like whirlpool

    you could try to blow all this out if you wish, I have done that before
    but finally found that after all the work ....it usually still boils down to a
    defective gas valve and or thermocoupling.....

    Last edited: Mar 15, 2008
  13. Russell Guillette

    Russell Guillette New Member

    Mar 14, 2008
    There is a place at the bottom of the water heater where you can stick a vacum cleaner in and also put one of those wire rat tail brush in and clean the little holes at the bottom of the tank. I had the same problem and changed every thing out but this fixed the problem.My tank is a little over one year old when this happened.
  14. haste502

    haste502 New Member

    Oct 29, 2008
    Stay away from A. O. Smith

    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.



    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.
  15. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    The second from the left heater looks like it is a sealed combustion chamber with a co-axial intake/exhaust pipe going to the exterior. But, if so, it would normally have an electronic ignition system.
  16. dargo

    dargo New Member

    Jan 9, 2010
    Funny, all out city installs is AO smith and they love them. If they were this bad with issues they would drop them like a rock. I have also not had a standing pilot light on anything NG product in over 15 years too so maybe that is half the battle.

    What bothers me is certain people whine about a little intake and plate cleaning on the bottom. Oh my god people, do you think it is install and forget? Have we gotten this lazy? It take about 15 minutes max to clean it IF you need to and that is removing the plate (sight glass) and blowing out both sides. It is like HVAC systems you do a once a year inspect. Or do you drive you car and never do anything after? I have to run a clean phase a a $1400 dishwasher once a month, on a $1600 clothes washer, clean the vent on the dryer every 4 to 6 months since it is a fire hazard and clogs...Even my furnace I take apart to CLEAN the flame sensor, clean the orifice and lube fan once a year. THis take about 20 minutes max and 5 of this is moving everything out of the way!

    Sorry I am new and will get nailed for this but certain people are making issues about brands that do not mean anything. And I visit lots of HVAC, plumbing etc forums and most times the same posts.

    To me most tanks are the same and not made in USA. Some last and some do not. It is like autos.

    Since I am one my #2 AO smith (last one was way old and worked great) is you do not have the dial to turn up/down water temp. You have the LED and it is too pre-set temps.
    Last edited: Jan 9, 2010
  17. spwill01

    spwill01 New Member

    Feb 4, 2010
    Louisville, KY
    I am having trouble with the pilot on my Reliance 606 water heater. I have cleaned the air vents at the bottom of the unit, checked the exhaust vent out the top and replaced the thermocouple with one from the company. This was a TC assembly that I got from Reliance. I still have trouble with the pilot going out. I can relight it after a few minutes but it still goes out. I watched it this morning and when the gas valve sensed correct temp and shut down the burner the pilot went out also.
    I this a bad gas valve and do I have to purchase it from Reliance?
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