AO Smith ProMax Water Heater Troubleshooting
By 
If you own an AOSmith ProMax GPST-40L Water Heater and are having problems with the way it is performing I’m sure the last thing you want to do is spend your hard earned money hiring a technician to repair it. Thanks to this constantly evolving, technology oriented world you have access to this very handy troubleshooting and repair guide. This guide covers many possible problems that could occur, such as: Temperature problems, noises, odors, leaks etc. If for any reason you feel as though you cannot safely perform these (or any other) repairs, please contact a professional technician.
PROBLEM: Water leaks.
SOLUTION: One of the causes of leaks in hot water heaters is when the hot or cold water valves, thermostat threads or other fixtures are not connected or sealed properly. You should always make sure that any threaded connections are secured and functional. Sometimes there might be leaks from other surrounding appliances or water paths so check to see if that is the case. One other cause could be condensation of the flue products, in order to correct this you should use some sort of cloth material to absorb the condensation coming from the exhaust vent (near the blower assembly).
PROBLEM: Water odors.
SOLUTION: Most of the time any odors in the water are due to high sulfate or mineral deposits in the water or increased bacteria counts. Too solve this problem it is recommended that you completely drain and flush the hot water heater and then refill it. Don’t forget to chlorinate the water as well.
PROBLEM: Vent pipe too hot.
SOLUTION: Commonly this is caused because the dilution air is too hot to mix with the flue gases or because there is not enough of it to mix with the flue gases. You should make sure that there are no obstructions internally or surrounding the air intake at the draft hood.
PROBLEM: Yellow flame
SOLUTION: The correct color of a flame for a water heater should be blue-ish, if your flame is yellow you should try cleaning the burner heads or ensure that there are no blockages in the air intake or exhaust venting in the bottom base pan.
PROBLEM: Not enough hot water
SOLUTION: First make sure the unit is plugged in and that the switch is turned to the “ON” position. If you can’t turn the unit on, make sure the electrical outlet you are using is working properly. Sometimes when the water is not heating up it could be a problem with the thermostat, in which case you will need to either check that it is wired correctly or replace the thermostat. Before you go to that extreme though, check that the temperature control knob is at the appropriate level. Another possibility is that the control harness or the blower motor might need to be replaced. Check to see if there are any leaks in the hot water connections as well as the external fixtures. Also be sure that the gas pressure is at the correct level, if it is too low it can cause the water to become cold too quickly.
PROBLEM: Reverberation or sizzling noises.
SOLUTION: Generally the reverberating type noise could possibly be caused by excess dirt at the bottom of the water heater tank. If this is the case you should try completely draining and flushing the unit and refilling it with chlorinated water. If you hear a sizzling noise it could be because of condensation dripping on the burner heads. Refer to the section on “water leaks” for instructions on how to fix the condensation.
I have an AO Smith hot water heater, electric, and we have terrible odor with the hot water. We have a well and a water treatment system provided by Culligan. This only occurs with the hot water. We have repeatedly drained the heater and that works for about 24-48 hours. Anyone have any suggestions?
Have had 2 water htrs at this home; 2nd is A O Smith. When it became necessary for 2nd, hoped prob was more w/old h2o htr — while it’d get far worse w/old, have read may be due to sediment that doesn’t flush out of bottom. Have learned if well water has high minerals, mine does, there is a bacteria created especially if set at typical 120F; when bacteria builds within the h2o htr it creates the odor. Raising the temp (have read 140F +) has helped, after flushing, add 2 pints hydrogen peroxide via either cold water intake or hot water out-take. If the out-take is a combo–connected to anode rod, creates some difficulty. Also funnel helps. Raising temp for brief time alone, helps, however resolution is short lived. Some a 2 gallon bleach & flush, though peroxide causes far less grief to people. Also problem can stagnate in pipes or drain — so flush the pipes either way. Bleach down drains may help that source. This all helps for about 3-4 mos. Have lived w/wells for 40+ yrs; this prop is 1st have known of this problem. It’s worse if you’re away for days and/or aren’t in rather constant use of hot water. Some say changing the anode rod to alum-zinc helps, if there’s no water softener; however, aluminum isn’t healthy good in water.
i have an A O SMITH HOT WATER HEATER NEW IN 2007
model GCV 30 100
problem = run out of hot water , checked it out ,, no polit
lite , turned everything off , turn baqck on turned polit to pushdown area hit stricker it lite , let burn for about 2 minutes then released polit button turn it to on then turn theom tate to lite burnner ,, it lite ,, burned maybe 15 seconds then went out
so tryed to lite agin nothing ,, turn everthing to off wait a few
min, would not lite at al ,, spark is working , but there is no gas for polit ,, so long as i dont turn the thermostate up the polit will burn ,, went ever i get it lite ..with that working
seems that the thermocoupling would be ok .. toke burner
out everthing seems ok ,, but odd to me there is a break
in the thormmo cupleing with a disk of some sort ,,never seen this set up before help tregg towery
I have a AO Smith ProMax M#GCV 40 160 Water Heater
Unit wont stay online. Pilot continues to go out. I can relite it and get main flame to fire. As soon as the tank satisfies on temp main flame turns off along with the piolit. Any suggestions?
Worst water heater in the world. Three years old has been repaired 8 times. LAst week again and one week later it’s out again. DO NOT BUY THIS PRODUCT!
we have a a o smith pro max gas water heater that is only 4 years old. When the fan kicks on it runs for a while but when the pilot kicks in it shuts off and no hot water. For a 4 year old unit we feel this should not be happening.
we have a 6 yr old GEV50-100 pro max. the flame under the hot water tank will not stay lit and you have to constantly relight the pilot flame. It is random issue. It may work for days or have to be relit 3 to 5 times a day.
we have reached in there with a broom head and vacuum to try and clean the pilot and ceramic piece up but that didn’t help.
I have a 50 gal PROMax
Model Number GPVH 50 100
System has a four pin Molex plug, I have a trouble shooting manual and it show a 5 pin Molex plug
contrfol show a error code 5, per manual
Water heater would start three times then lock out
I followed the instructions and cleaned the flame sensor
Now it will not even attemp to ignite, but starts then goes right to error 5, does not do the three failed ignition attemps
Why does my heater keep going on to vacation mode? How do I correct it?
ProMax GCV 40 100; burner won’t stay on. I reset the pilot, turn up the burner, goes on and heats the water (mostly) but that’s it. Have to keep resetting pilot to keep producing hot water.
Anyone?
the pilot assembly is bad when you take the 2 screws off remove the burner turn it up side down there is a small round looks like a watch battery there is an apoxy on it that drys out and becomes brittle.will not let it stay lit due to concact.pilot assembly need to be replaced.beware it will only last about a year or 2 its a bad design
I have this same water heater. There are 2 things that cause this problem. One is the filter on the fron and then the filter under the burner. The burner does not get enough air, so it turns the gas down until it gets little air and shuts itself off.
My water heater will not stay lit.
I have an A O Smith water heater and it was installed by a licensed Plumber that I always thought was the best plumber there is,and he could not lite the pilot lite and we had to have someone from the place we bought it from.They sent a guy out to lite the pilot and commented didn’t the guy know to make sure there was no dust in the combustion chamber.Charged 150.00dollars and in 10 minutes he was gone.Doesn’t seem very fair to me.
Can anyone call me and tell me how to fix this problem or do I have to pay a plumber to come out to spend 10 minutes to lite it and walk away with 150.00.My home phone is 773-267-5511.Please help me,Thank you
I installed a pro max 40 gallon gas hot water heater my customer complains always has to relate pilot. I changed thermocoupling and gas valve and still have problem. Cleaned filter screen also gas pressure is between 7.5 and 8 inches,I’m lost
I had an A.O.Smith Pro Max 40 installed Aug,2010. After a few months only the hot water smelled very bad. The plumbing co removed a completely destroyed anode and replaced it with another of a different alloy which lasted only a few months before it was wasted. A third anode was installed more than twice the length and of yet another alloy. Each time the tank was drained flushed and chlorinated. Today after over 700 dollars in parts and labor our hot water still stinks. Our water is from a private water company that serves over one hundred homes. Stinking hot water not typical for other homes served by this water company. We also use a water softening system. Is there a solution???
Heater keeps going out. I relight it and it comes on for about 30 seconds. We have not hot water, does anyone know what I should check. It’s a gas heater and the gas is ok. I turn it to off and in 30 minutes I go through the steps for lighting it and it will come on and about 30 seconds later it goes out
You should do the research to comprehend the services that are provided by these companies.
She graduated with a dual major in both English and Secondary Education. This is less
likely in the case of Indiana because of the lack of a statewide requirement.
The company is ISO 9001 and 14001 accredited that provide requirements for wholesale batteries.
As a brand they push the concept of the 3 R’s of preserving resources and
sustaining the environment: reduce – reuse – recycle.
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Many thanks for providing this info.