Water Heater making loud gas explosions in bottom of pan

[Bob from accounting]

Just got done draining and swapping out an anode rod.
Turned on the gas and main burner and massive booms at the bottom of the tank thundered out.
Like gas being trapped or gas air bubbles. Boom booom. Freaked me out, turned off the gas and the water heater.
I will call a plumber but wanted to get a since of what is going on here.

 

[Sarg]

I assume you fully filled the water tank ? Opened the hot water faucets and let them run until all air expelled ?

 

[Sponsor]

 

[WorthFlorida]

If you turned on the gas first and little or no water in the tank, the little water turned to steam very fast OR when you turned on the water it hit very a hot surface and instantly turned to steam. It's what Sarg was suggesting.

 

[Bob from accounting]

The water tank is full. The explosions are at the bottom near the main burner. I can hear the main burner on, and then with in 10 sec there is a loud boom and you can see a gas explosion underneath. Feel and sounds like a pocket of gas that ignites? Or there is pressure below, three year old tank, hard to believe there is too much scale or debris smothering the burner?

 

[Bob from accounting]

If the homes lines had not been fully bleed of air, but the tank was full, would that really cause these small mini explosions under the burner? I am questioning if the entire house was bleed of air, which I am not sure was the case? Again, the tank was full one utility sink bled the air and the upstairs did have air in the lines. Could that have something to do with it?

 

[WorthFlorida]

Something is going on outside the tank in the burner area, nothing to do with water. You first want to open the access panel, with the gas off, and inspect the area that there are no critters or obstructions. Here is a short video on gas water heaters on how the ignition process operate. I'm assuming you have an ignition type burner, the gas turns on but the igniter spark is delayed causing gas to build up them boom. There could be other reasons.
Does it continuously happen while heating or only once per heat cycle?
What is the model number? If you have a video, upload it to YouTube or another site and then link it from here. Pictures you just drag and drop.

 

[Reach4]

Sounds like a gas leak. I am not a pro.

I suspect the diagnosis will be that you need a new WH, but it is possible that your plumber will change the burner assembly.

 

[Bob from accounting]

We asked Rheem to ship out a new burner assemble. The plumber lit the burner and as it burned. wait for it wait for it, then boom, loud big combustion near the burner, boom. He was like yea something is wrong with the burner. He said lets get one here in hand before we open this all up and pull it out. So we are waiting now for a burner and the hope is that solves this. We did not open anything up yet. He has not really seen this before in 35 years, seen something similar in ground boilers once or twice but not in a Rheem water heater like this.
If anyone had this happen years from now, here is the model number PROG40-38U RH62 EC1.
New burner is on its way will be a few days with out hot water. Wife if not happy with me.
All I did was, swap out an anode rode, heat trap nipple, 3/4" inlet ball valve and a new supply line, everything went perfectly and now the burner has a gas issue. Go figure? Hard to believe this is not related, I must have done something and I am taking the blame but still hard to see the connection between what I did up-top and now we don't have hot water. Grrrrrr!!!

 

[Reach4]

Vibration from the impact wrench may have triggered something ready to go anyway.

If you did not use an impact wrench, maybe you turned the entire WH, and that stressed the gas pipe.

 

[Bob from accounting]

I used an impact wrench. It worked pretty seamlessly , once I broke the nut, I used a breaker bar from there, so the impact wrench only spun the nut about a quarter turn. Not a ton of time with the wrench, but yes, that is a good suggestion as to how that vibration could have be the culprit. Probably the case.
Three year old tank, such a bummer that the burner has to be replaced. We will see how this goes, fingers crossed.

 

[Master Plumber Mark]

I used an impact wrench. It worked pretty seamlessly , once I broke the nut, I used a breaker bar from there, so the impact wrench only spun the nut about a quarter turn. Not a ton of time with the wrench, but yes, that is a good suggestion as to how that vibration could have be the culprit. Probably the case.
Three year old tank, such a bummer that the burner has to be replaced. We will see how this goes, fingers crossed.

So you now got your wife on the war path for screwing around with an anode rod that you probably
could have been left alone....
you are lucky that the booming thing did not really flare up and take out the fire safety glass vial under the burner assembly ---- I assume that the plumber did look to see if the glass vial has not broken and tripped the air chamber shut???

if this happens then you are seriously boned....and you will need a new heater...

good luck

 

[Bob from accounting]

you are lucky that the booming thing did not really flare up and take out the fire safety glass vial under the burner assembly

From what I can tell about the Thermal Release device, the "glass vial" and looking to see that the burner does still ignite and turns on and stays on during the booms. If that TRD was popped due to excessive high heat, the main burner would not work. I think that device is still intact. Thanks for the heads up on that.
The anode rod had corrosion but like you said may have lasted longer? But now I have a segmented rod in there and the hex nut is not factory tight for future replacements, it is just human tight with a breaker bar, another words I hope to not to use an impact wrench ever again. I have the tools needed to maintain this in the future. I was dreading having to cut the rod in half to pull it out, but that is now done and I will never had to do that again. Doing all this work while my warranty is still good, nice to get all this labor and parts replaced. Kinda like if I am going to break something do it now before you gotta pay for it all. So yes I am lucky.
Learning comes with a cost, but the hope is I keep getting better troubleshooting and working through these things and minimize my mistakes.

 

[Sarg]

I suggest you should plan on checking the anode rod about every four years. If you maintain the heater with a good anode rod the tank will last decades.
I just installed a new electric unit and have already got a couple anode rods ready on stand-by. The biggest improvement over factory was I replaced the plastic compression drain valve on the Rheem unit before installation with a 3/4 ball valve designed for flushing the tank. Historically ... when we serviced our old heater every year we would replace the elements and use a wet vac through the bottom element hole to get the sediment out. With this new valve I hope just a flush may get most of it out.

 

[Bob from accounting]

Rheem model number PROG40-38U RH62 EC1
SP21022 burner replacement

For any future inquires, I had a water heater installed 3 years ago, they hooked it up to the old 3/4" existing cold hot water valves. This valve had a small leak that started to rust the 3 year old heat rap nipples.
So I figured if I was going to replace the ball valve, I should also replace the rusted heat trap nipple, and after three years should check the anode rod while I was there, do it all in one go.
Went seamless, I used an impact gun for 20- 30 sec off and on to loosen the nut about a quarter turn, then I used a break bar from there to slowly turned it and wheel it off. Hacked sawed it out, replaced it with a segmented anode rod, and got the heat trap nipple replaced as well as new ball valve.
Padded myself on the back and the turned it on.
The burner fired up, no ignition delay, burner is on and roaring, with in 10 sec boom, combustion chamber filled with gas and combusted.
So we ordered a new burner under warranty, swapped it in and it has been working for a day.
No one really knows what happen, other than some extra gas was filling the combustion chamber while the burner was lit, and then once it got close to the open flame it would explode. We never found a hole or anything, the burner looked pretty good shape. The impact gun must have scared the burner so bad it formed a hole somewhere. We will never know. Thanks for all your help.

 

[Master Plumber Mark]

That’s simply not true.

Rheem will ship out a TRD ( thermal release device ) as they have for me several times.

Of course Rheem will send you any parts you want...
it might take up to a week to arrive and then you got to
stand on your head and hope to reach in there and install it
correctly......

it is probably just wiser to install a new unit and forgo any other issues
that might be going on with the heater....
.

 

[Master Plumber Mark]

I have attempted to save the customer the expence of a new water
heater by fooling with those peanut vials,
but I found it to be nothing but trouble... Their is always a
reason the unit over heated and it shut down for safety reasons..
I have seen one where the baffle up the center of the heate melted and was all warped

the liability issues bothered me trying to do someone a favor that might
come back and bite me down the road....

I got a picture somewhere....