Loud bang from toilet

Hi everyone New poster!

I would consider myself below a newbie in the plumbing world. This is my story any and all help needed.


So last night my wife and I are watching the Packers/Bears game and all the sudden we hear a loud bang. I look at my wife we think some one is breaking in. I run up stairs and hear water running in the guest toilet. We never use this toilet and what do I see? Out tank lid is almost completely knocked off the tank?? What looks to be the fill valve has "exploded" Or just shot up and kicked the tank off. Does this happen? If so any reason?

I shut the water off and drained the toilet. I pushed the valve back down in its rightful position turned the water back on and flushed with no problem. I drained the toilet again and shut the water off. Any thoughts would be wonderful.

The toilet is stamped and dated from 1990 in the tank. I'm not sure who made the tank but that's all I got.

At this point I will be replacing the toilet 4GPF -->1.28GPF

Now im just very curious with what happened. Is it from pressure because I never use it? Is my water pressure high? We have been in the house for 5 months now and it just happened 20 minuets after my wife got out of the shower. Any help would be awesome!

The water pressure might be high. Also, what toilets are you looking for to replace this toilet from 1990?

I would love to see a picture of that.
I have heard of cases like yours. Not often, but it happens.

I haven't really started looking for a replacement yet but I will look at Toto.

If the water pressure is high how do I find out? And what should it be. And if it is high what do I do?

Not to play devils advocate but it the pressure was high would I be getting the same problems all over? Everyone in a while after a shower/dishwasher I will turn on the faucet and get a big burst of water for a brief second.

I wish I would have taken a picture but in the panicked state that I was in I just started doing things.....Not thinking.

Terry, when you say it happens do you know of any reason for this? Is it a problem with the toilet or the plumbing in general?

Any hardware store will carry a pressure gauge that uses hose threads. Put that on the outside hosebib and get reading.
You can also use a washer valve inside, which is more accuraet if you already have a PRV on the incoming cold.

Anything more than 80 PSI needs reducing. Between 50-70 is nice.

I'm thinking POSSIBLY a fill valve failure, was that fill valve old in that toilet??

Not really sure how old the filler is. I just moved in the house about 5 months ago. The toilet is from july of 1990.

Does it make any sense that this would just happen. I mean we haven't touched the toilet in 2-3weeks?

Without knowing brand and model, it's just a guess.

There are quite a few fill valves that could be in your tank twenty three years later.

Is the fill valve yellow?

Looks like a Fluidmaster 400 series ant siphon

toilet is Crane plumbing

must be a crane radcliffe if it's from 1990. I like those toilets...

If you didn't catch my reply on the other forum, I'll just repeat it here too. Aside from a defective fill valve and the high pressure, check your meter or water service for an existing pressure regulator that may have gone bad and also for a back flow preventer. High pressure can be made worse by thermal expansion and do exactly what you have described. You may also already have a thermal expansion tank near your water heater and it may have failed as well. But as the others have stated, check your pressure first. If you have a regulator already installed there are a few tests we could walk you through to see if it has failed or needs some adjustment. First is an example of a pressure regulator and second is an example of a backflow preventer if you are not familiar with what to look for. They are typically located where the water meter is and where the water enters your home.

Adding attachments. These are reversed picture taken on laptop.

Is the thicket piping right above the blue tank the regulator? This is where the black plate with the info was.

ok now I feel like a idiot..You caught me on two forums with the same question.

im looking at my hot water heater now. looking dead straight at the water heater about 3 feet up the copper pipe on the right is a blue tank"proflow" water heater saftey tank model PT-5 pre charged pressure 40psi.

above the tank i see plate that says
water dual watts check water regulator asse 1024 size 3/4 x 3/4 mod 7112-2

i dont see any adjustment for this at the tank.

so above the tank is the back flow preventer?

Here's the deal. That's definitely a check valve above the blue tank, but not a pressure regulator. The pressure regulator would usually be right near where the pipe from the street comes into the house. If your meter is inside, it would be near that.

As you may have picked up from reading here, you may have a "closed" system. That is one where there is either a backflow preventer or a check valve or a pressure reduction valve with a designed-in backflow preventer or a water meter with a backflow preventer. The idea is that if water gets contaminated in your house (i.e. by dropping an outdoor hose in some pesticide and then draining your system, sucking the pesticide into the house water), it won't flow back into the water main on the street and contaminate other people's water. So it's "closed". Water can come in but can't go out. (An "open" system has no such restriction.) In an open system, if the water expands due to heating, the expanded water will just flow back to the street main without raising your house pressure. In a closed system, it can't do that, so if the water expands due to heating, it has noplace to go and the pressure builds.

You likely have a closed system. To compensate for the expansion of the water when your water heater is running, you have an expansion tank (the blue thing). If that's functioning properly, it will absorb the expanded water and maintain the pressure. If it is waterlogged or worn out or needs to be recharged, it won't. Terry is right to check your pressure with a gauge, but you want to do it when your water heater is running to make up for hot water used in, say, a shower or the dishwasher or the clothes washer. A gauge that you can leave attached for 24 hours and will register the high mark with a little needle will also do the trick.

My guess is that your pressure is probably decent most of the time, but climbs after you have taken a shower or run the dishwasher. Maybe it was enough to pop that valve up. Or maybe the valve wasn't locked at whatever height it was set and it just twisted loose and shot up in the higher pressure (or standard pressure).

I would certainly make sure that that expansion tank is working.

Good luck and let us know.

In the photo to the right of the blue tank (thermal expansion tank) looks like the backflow dual check. But remember, as stated before by terry and starwarsith, it is important to check the incoming pressure with a gauge. Is your water meter in the house? I don't see it in the photo. If it is outside in a pit, that may be where the pressure regulator is located, if you have one.
Since it is obvious that you do have a check valve and thermal expansion tank (from the photo) you could also check to see if your thermal expansion tank has failed and it's easy to test the bladder inside.
The little blue screw cap on the top of the thermal expansion tank has a schrader valve under the cap. It the same as on a bike or car tire. Remove the cap and press on the middle of the valve as if you were letting some air out, for only about two seconds. The only thing you should get out of it is air. If water comes out of it, the thermal expansion tank bladder has gone bad. Replace the cap after testing. If you get only air, testing the air pressure left inside is another matter for another day. It's still priority to get a water pressure gauge that can screw onto a hose connection and test the pressure in the house with no water being used.
Let us know what you find out. The other members in this forum really know their stuff when it comes to toilets and problems like this and the more info you have the more they can help.
Edit:
Sorry, wjcandee. I must have been typing when you posted and didn't see you already responded.

Ok you guys are awesome! My meter is outside embedded in my driveway. I opened it up saw some things again i have no clue what im looking at but learning. Yes after shower/laundry I get a burst of water from my faucet just for a second... Do you see this as a major problem? Will most plumbing companies be able to fix this?

So when I test the pressure at my hose do I leave it on for a few seconds or longer? If it is over 80PSI I assume thats another problem.

Another question relating on another toilet. I opened the tank and noticed a kink in my bowl refill line. No water was being put in the overflow. So I moved the hose around and now the water flows free. Is this important? I was told it is to keep the bowl clean? That sounds like a lie.

And with the original problem toilet right now I have no water in the tank and very little in the bowl. I have the water shutoff to the toilet via the emergency shutoff valve. Is this ok?

Thank you all so much.

24 hours would be good. Get one like this what remembers the peak: http://www.homedepot.com/p/Watts-3-4-in-Plastic-Water-Pressure-Test-Gauge-DP-IWTG/100175467

A classic symptom of thermal expansion is a sudden rush of higher pressure for a moment, especially in the mornings when water is first used. Some people don't notice it because the first use in the morning is a toilet flush, but try opening a faucet first and see. This can be verified by checking the expansion tank as described before. The tube that fills the bowl is to prime or pre-fill the bowl before the next flush so that there is a good siphon of the bowl water from the tank water that enters it. What cleans the walls of the bowl is the regular flush to get rid of the waste.
So, I think we are confident that you are having thermal expansion issues, but there may be more. Keep following the testing advice and if you can get a good picture of the inside of the meter pit, we may be able to determine if you have a regulator and if adjusting it will help solve one of your problems.
Leaving the toilet off should be fine. Hope you have others you can use. With a fill valve already blown, I wouldn't want the same one to blow off again when you're not home since it already has been damaged.
Any plumbing company should be able to fix all of this for you easily. It's usually more a matter of money and trust. To your benefit you also will have plenty of information from this forum should you choose to go that route.

Caduceus, enjoyed your excellent, concise explanations of everything!!