Water Heaters - Electric Water Heater Leak

The top of our electric water heater has three pipes coming out of it: two that is connected to our water line throughout the house and one that is connected to nothing. It's an open pipe that goes away from the tank and down to the ground.

Two years ago, this open pipe would spit out a little water occasionally when the water is in use. Therefore, my plumber connected a small expansion tank on one of the pipes above connected to the water heater. This stopped the spitting of the water from the open pipe.

Currently, the open pipe is spitting again when the water heater is in use. What is wrong? I placed a bucket undernet that open pipe so water doesnt collect all over the ground.

Is my tank shot? I know the tank was installed in 2005 and I believe there is still a manufacturers warranty.

Please help!

Not a plumber, but until they get here....
2 things come to mind. Your expansion tank may no longer be doing its job. I believe they can become waterlogged over time. The air in the tank disolves into the water and it can no longer compress the way it is supposed to. If you have any model numbers of the expansion tank, it would help the experts. It MAY be able to be drained and repressurized. If not, they are relatively cheap and simple to replace.

The other thing is your temperature and pressure release valve (commonly called a T&P valve) may be bad. It is what the open ended pipe is connected to on the WH. It seems to be doing what its supposed to, since it is not leaking all the time, only when the WH is running.

I'll get the expansion tank model number when I get home later.

How do I know if the T&P valve is bad? Is that usually covered under a manufacturer's warranty?

Hmm well, like I said, the bad ones I've seen leak all the time. I'd have to let someone else answer that. As to warranty...I don't have a clue, but I doubt it.

I've seen a few relief valves only leak when the heater is calling. You get some expansion when the water is heated and although unlikely, the relief may be getting weak enough to let some water pass by during this time. But as stated before, they usually leak all the time once they've gone bad. The good thing is that they don't cost very much and are easy to replace if that is the problem.
The tank could be the problem. You could check it by valving it off and draing the system, then check it with a tire pressure guage to see if it's in fact holding any or enough air.
I've seen a few where the tank/bladder is still good but the "cup" ,as I call it, gets caught sideways in the bottle neck of the tank and causes the tank to not operate properly.

I'll have my plumber take a look at the expansion tank.

In the meantime, would it be OK to connect a hose to the T&P valve to a floor drainage instead of a bucket?

Don't see why not. Make sure it doesn't slip off or anything.

btw...looked at a few places, you might try moving the lever on the T&P valve side to side a bit. You can lift it part way, wiggle it a bit, then let it "snap" back down. Turn the water supply off first. Keep a bucket under it, you'll prob get some water.

Still think its prob the expansion tank though, since it was ok for 2 yrs.

Does expansion tanks really go bad after two years? How can it go bad?

I think it depends on what type of tank, whether it had a bladder separating the airspace from the water, quality brand, etc.

Heck, you never had a brand new car, lawnmower, electronic item break down? lol

The manufacturer pf the expansion tank is a Watts Regulator and the model number is DET-5.

Does anybody know anything about this expansion tank...life-cycle, etc?

I'm a 1st time homeowner so please forgive me for some dumb questons:

1) Do all water heaters come with an expansion tank?

2) If the WH does not have an expansion tank, is it normal for the T&P release valve to spit out water?

3) If yes to #2, then is installing an expansion tank the solution?

4) In my situation, if there is a problem with my expansion tank and instead of replacing it, I just connect a hose to the T&P pipe and let it drain somewhere can I make this a permanent solution? Will I be hurting the WH if I leave it this way?

Ok, remember, not a plumber here. But lemme try to answer as best I can.

Many places require expansion tanks now, I believe. Not sure why. Both the places I've lived in DID NOT have them, and never had any issues. May have something to do with type or pressure of water supply.

I don't know whether its NORMAL, but it can happen in some situations (see above). I have seen posts on here about people curing that type of problem by installing a tank. I have also seen it recommended that they be installed during the replacement process, to avoid such issues.

You could probably do the replacement yourself if its necessary. You may only need to recharge the air, again, not a plumber.

No, I don't think leaving the hose on, and letting the spitting continue is a good idea.

I don't know why any of the plumbing guys haven't responded. I'll PM a couple and ask them to take a look at the thread.

Hi all, Sorry I am not here as often as I should be right now.

I did not read all the posts here but I think I can help you out here.

If the relief valve is blowing off, (spitting) only while the water heater is reheating, it is most likely caused by a bad thermal expansion tank. Unfortunately some of these tanks do not last very long. To test the tank pressure, using a air pressure gauge, check the schraeder valve on the tank. If water comes out or there is 0 pressure the tank is bad.
To further test this, get a water pressure gauge that hooks to a hose connection, and sold at most big box stores for about $10.00. Hook it up to a hose connection someplace in the house, (sillcock, laundry sink, water heater drain, etc.).
Once the relief valve starts to spit, open the faucet and read the water pressure. If you are reading around 150psi, there is something wrong with the Thermal Expansion Tank and it most likely needs replacement.

If the valve leaks all the time, or if the water pressure only reads less than 80psi, the problem is most likely the relief valve.

All homes need thermal expansion tanks, or protection as the code states. If you have a well and no Pressure Reducing Valve after the water tank, you will not need a TET because the water tank will do the job. If you have city water and have no PRV or check valves between you water heater and the water main, you should not need one either. All other instances will most likely require a TET. In my city it is a requirement for all water heaters.

If I buy a new expansion tank, is it easy to install rather than troubleshooting my existing one?

My current one seems to just be twisted on.

Shut off the water and open a drain or faucet to release the pressure. Then remove the old tank by un-threading it, (careful, it may be quite heavy), before removal, have the new tank ready with thread sealant, (teflon tape or pipe dope), and have an extra person with you. Once you loosen the old tank, have the extra person remove that tank, while you are ready to install the new tank. Quickly install the new tank and minimal water should be lost. Turn the water back on.

When I remove the old tank, will water be coming out of that pipe?

Will the new tank already be pressurized correctly?

Some water will most likely come out unless you drain the whole house down, and even then you can get wet. Just have a bucket close by.

The pressure should be checked, but if you cannot, it will come with an average precharge.
To set the proper pressure on the tank, you need to know the static water pressure first, then adjust the tank pressure to 3 lbs under that pressure

I have not replaced the expansion tank yet because I am now realizing the T&P valve is dripping water even when nobody is using hot water. How long should I wait or how long will the T&P valve stop dripping after someone uses the hot water. I want to make sure it is not the T&P valve that is wrong before I replace the expansion tank? How can I make sure?

Someone told me to knock on the expansion tank when hot water is not in use and if you hear a solid knock then the problem is the expansion tank. If the tank sounds hollow when you knock, the expansion tank is fine. Is this true?

I replaced the expansion tank but the overflow pipe still drips. The expansion tank was filled with water. I noticed there was sediment buildup in the pipes when removing the expansion tank. After removing as much sediment in the pipe and manually flushing the t&p valve hoping to flush more sediments out.

Do I need to replace the T&P valve?

Will the new expansion tank fill up with water again if the t&p valve needs to be replaced?

Quite often once the relief valve releases water, it will have a tendency to drip from dirt getting into the valve, especially if the valve has not been used for a long time. Most often this will cause the relief valve to need replacement. On occasion, you may be able to flush the valve out by blowing it of a few times, but be prepared to replace the valve.

DO NOT JUST CAP OFF THE VALVE until you get it repaired.

This is a safety device and should be fixed immediately.

Get what repaired? I have a new t&p valve that I plan put in. Will that solve the problem?

Probably so....here's the basics.

Do the same as when you replaced the expansion tank to relieve pressure.

What kind of connection is the pipe to the T&P? If its soldered you may have to cut it to turn the valve.

Use tape on the valve threads, but don't let them overlap into the opening. Leave 1 thread at the end clear.

Have someone hold the WH as you take the valve off, you don't want the whole thing twisting and moving. The valves can be real tight sometimes.

It's the connector that I can use a plumber wrench to take it off from the t&p valve?

Is my new expansion tank getting damaged because of the damagaed t&p valve?

Should I remove the new expansion tank and pour out any water if any in there since installing it?

Good, threaded fittings are easier than soldering.

No, it shouldn't be hurting your new tank.

No, tanks will always have some water in them, it's the way they function.

Keep your receipt for your new tank in case it fails again in warranty.

I'm sorry MikeyBoy if I confused you with my response. By "repaired", I meant, either blow off the existing valve or replace it.

Gunguy45 has explained all your other questions as I would have.

I have now changed the expansion tank and t&p valve and water is steal leaking. It's definitely a lot lot less than before but it still leaks. I emptied the bucket before we left the house today and came back 6 hours later and there was little water in the bucket.

Since nobody was in the house using the hot water while we were out, is it now the water heater that is the problem?

Was I supposed to flush out all the water after installing the new t&p valve?

What should I do next?

I guess at this point we need to know the highest incoming water pressure. The best way to do this is purchase a hose thread mounted pressure test gauge. The big orange stores carry one from Watts for around $10.00. It has a high point needle that you set to zero when starting. Hook the gauge to a hose connection,, eg: washing machine hook-up, water heater drain valve after flushing it out first, outside sillcock (only if warm enough climate), etc.
It needs to be a place that you can leave this on for 24 hours.
Once the water is turned on, read the static pressure reading, then check it again in 24 hours. Check for the highest recorded pressure gauge reading

Please get back with that info to continue

I installed the new t&p valve last Friday and I noticed little water dripped on Saturday, none on Sunday, very very little on Monday and nothing yet today. Does it take a while for the t&p valve to get situated? Is this normal?

No, that is not normal. You need to do as I asked in the last post. I am assuming by now that you are on city water. I am wondering if the water pressure has gone up in the mains. Also, do you have a pressure reducing valve on your main line near your meter?

If the city water is at 125 psi, it will be very hard to stop the RV from leaking when running without reducing the incoming pressure. If you already have a PRV, we will need to find out if it is working properly.

Just in case I need to add more air pressure on the expansion tank, how do I do that? Do I have to shut water and electric off first? Can I add more air pressure while it is connected or do I have to remove the exansion tank? Is it OK to use my air compressor that I use for my car tires?

I worked for a meter and backflow services company. My job was for six months, was to install thermal expansion tanks. We always set the tank pressure before installation. I feel it will give you your most accurate reading. Tank pressure should be 3 psi under the static water pressure of the home

If you were to shut off the power and the water to the tank, then draw off water so the pressure drops to zero, there will no need to remove the tank for adjustment. Let me know what happens and I am still waiting for the water pressure readings.

I plan to buy a water pressure reading the next time I go to Home Depot.

After I shut off the power and the water to the tank, how much water should I drain out?

I noticed that my previous expansion tank came pre-charged at 40psi and this new one came pre-charged at 25psi. When I installed the previous expansion tank, the leak stopped. With this new tank, the leak is not completely gone. Does this lower pre-charge on the new tank play a factor here or it does not matter what the pre-charge psi is?

Just drain out enough water so nothing comes out of the kitchen faucet. Then you know the pressure is down. If the new tank came precharged at 225psi and should be set at 70 psi, that will make a huge difference. To properly set the tank pressure and size the thermal expansion tank, you need the water heater capacity in gallons, and the incoming(static) water pressure

Then if you go to amtrol.com you will find a chart to use for sizing the proper tank.

I followed your advice. I shut off the power and water to the tank. I released the pressure in the t&p valve until no more water came out. I took a tire gauge and checked the pressure of the tank and it said 10psi. I added enough air to make it 40psi to make it similar to my previous pre-charge expansion tank. I turned the power and water back on. If I shut everything off and release all the pressure in the t&p valve again, will the expansion tank pressure drop to 10psi or 40psi?

Is there anything wrong with what I did?

I know the water heater is 50 gallons. I will get one of those water pressure gauges from Home Depot to determine the incoming water pressure.

Lowes only has two expansion tanks: under 52 gallons and over 52 gallons. Is that not correct?

What you did sounds fine, but I would have waited until you had your pressure reading as you may need to do this again. 40psi is just a default setting (average), set by manufacturers.

If you go by a real plumbing outlet, you will find there are quite a few more sizes available, with 3 of them for most residential systems.

Read this chart

http://www.amtrol.com/pdf/TXT%20Sizing%20ChartsMC8520.pdf

Totally understandable. I'm just curious why the one I bought from Lowes is pre-charged much lower than the one in Home Depot.

If I shut everything off and release all the pressure in the t&p valve again, will the expansion tank pressure drop to 10psi or 40psi? This is just a learning thing for me.

I just connected the water pressure gauge on the cold laundry side and here are the results:

1) When I turned on the water, the gauge jumped to about 90 psi. When I open the faucet, the pressure drops but when I close the faucet the pressure steadies between 80psi - 90psi.

2) When I turned off the water and released all the pressure, the gauge read almost 140psi. This is with the tank connected.

3) When all the pressure was released, I added more air to the expansion tank to approx 55psi where initially it had about 40psi. When I turned on the water again, the gauge went back to approx 90 psi.

So, what is wrong? Is my expansion tank not working? Is it too small? I called the town and they did not increase any water pressure. Please keep in mind, this was all working fine with no drips a few months ago. The only thing we did within that time is winterize and blow our irrigation system but we do that at the end of every summer.

I also I have a pressure reducing valve after the water meter that looks old. Should I try loosening the check nut on the prv counter clockwise to lower pressure?

I checked the water pressure this morning and it is back to 140 psi. What is wrong and what needs to be fixed?

I'd let one of the plumbing experts reply before doing anything.

Your pressure is way too high. I'm not sure why you have 140 PSI, thats just not right. I didn't even think city systems ran that high.


Ahhh I see Mark is on...I'll shut up now

The expansion tank should have a pressure charge of at least the lowest reading you saw which was between 80 and 90psi. I would charge the tank to 80psi.

If your water pressure coming into the home is more than 80psi, you should be installing a pressure reducing valve. This way you can lower the water pressure to about 60 psi, which will assist in the water heater problem and will definitely stop future plumbing problems from arising, such as fittings blowing apart, or toilet valves as well as dishwashers from breaking down.

Make sure you do not already have one of these that is just not working..

If you do install a PRV, remember to adjust the pressure tank to 2-3 psi below the set pressure of the regulator.

Hey Gunguy, keep talking like that and I will get a swelled head:eek:

:):):):coffee:

Hey MikeyBoy,

Now that you have the info supplied, have you checked the chart I sent you for sizing your pressure tank yet? If the pressure tank is to small or improperly charged, that would be the reason for the 140psi readings. But the 90 psi reading is still very high and should be controlled with a PRV as per plumbing code.

OK, Mark...yer head can unswell now. He said he has a PRV installed, but wants to know about adjusting it. (last line of post #37)

See, even the gods are not perfect. I must have missed that one, but I can use the medication or pain card to get me out of it. :rolleyes:

Just kidding.

and thanks for pointing that out to me.

Mark

P>S> after re re-reading post 37, which I read hours ago. It seems he has edited the post and that info was not in the original post. ..... or at least I think that is what happened. Its my story and I am sticking to it.

MikeyBoy,

After re-readong post # 37, it seems that the PRV is not working properly, and if it is as old as you claim, should be replaced, as it will take longer in labor to repair the old one if the parts are even available. A watts U5-B is a 3/4" PRV and is only about $100.00, and there are cheaper ones out there.

Here is what I would do if I were at your home, given the information we have at this time.

I would replace the PRV.
Then set the pressure to not more than 65psi. To do this, make sure there is nothing in the house running and the water heater is electrically turned off. Open a faucet to relase any excess pressure in the lines, then close faucet and take pressure reading. Adjust until you get to 65 psi.

Charge the expansion tank to 63psi

Turn the electric power to the water heater back on. Open all faucets to bleed out any air and check the pressure setting. Should be at 65psi. Leave gauge on and use the hot water until the tank starts to reheat then shut off the water. Let the tank go until it re-heats to normal storage temp. Check pressure gaige. It should have only gone up a few degrees. If it has gone back up to 140degrees, I would replace the expansion tank to a larger size.

Sorry, I did not see all the new posts. Thank you!

Since I need to replace the prv, do I have to put it in the same place right after the water meter? I had an irrigation system put in a few years ago and I was wondering if the new prv can be put in after the outgoing pipeline for the irrigation system so I can have increased water pressure for my sprinkler system?

Well, if you are starting with pressures over 80psi, I would say it is not doing its job.

You can try the adjusting screw on the top to see if the valve even works, but it appears to me the valve is leaking by, and will be hard to find replacement parts.

MB....don't know if there are any kind of rules about where the PRV goes, but if you really have 140 PSI you might be asking for trouble with your sprinkler system if you relocate the valve.

Oh, and no kind of sprinkler expert either, just bringing it up.

Yes, you can move the PRV to after the irrigation system, but you will want to know the exact pressure coming in, without the interference of the water heater, and you may want to check with your Irrigation installer or service center, as changing the pressure will also change the operation of the heads. And as Gunguy said, there may be a maximum pressure for the irrigation parts, piping, valves, heads etc.

Is it normal for the check nut on the prv to be completely tight like it was closed all the way? I have never touched this since we moved in over 2 years ago.

I loosened it a lot, then closed the cold laundry faucet and waited for water pressure gauge to drop to zero. Once it hit zero, I turned on the laundry faucet and the pressure jumped to 60 psi instead of 140psi when the check nut was completely tight.

Is this normal? Is the prv OK? What else can I check?

When I open the cold water in a regular faucet, the pressure gauge drops to 30 - 40 psi.

I will now wait to see if the gauge will go higher than 60 when no faucet is in use.

Let this sit overnight and check the gauge in the morning. The problem here is we are trying to diagnose two possible problems at the same time. I still feel the 140psi is caused by the expansion tank and the high intake water pressure. If you could shut off the water heater electricity for an evening, and check the gauge in the morning, we would be able to get an accurate high pressure reading (static pressure). This is the best way to individualize and test the PRV aside from the pressure tank. If the Electricity to the H/W tank is off, and the highest pressure we get is 60psi (aprox), then you power up the water heater and wait a half hour, if the pressure rises, the problem is with the tank. If you have a pressure reading before turning the water heater back on, of anything above the original static pressure once adjusted this afternoon, the expansion tank is either not doing its job or the PRV is leaking by, or a combination of both.

I woke up this morning with the pressure gauge at 70psi so will we assume that the prv is doing its job? The only problem I see is that when I was taking a shower and my wife was using the faucet in the kitchen, you can feel the pressure in the shower dropped. I will have to test the pressure with two showers running at the same time.

I examined my pipes in the basement and they are on the smaller side so is that why I need more pressure to compensate for the small pipes. What psi should I keep the water pressure at to keep the people in the house happy and still prevent any damage on the water heater, expansion tank, pipes and yeah prevent the t&p from spitting?

what is the static water pressure now? 70psi is about as far as I would go. When the hot water is heating, do you see any large differences in the pressure? If not, this is fine.


The problem of a lower water pressure could actually be another problem entirely. I was at a job recently that had a static pressure of 110psi and would drop to 10psi when running a faucet. The third floor was getting no pressure as it takes pressure to produce altitude.

It is common for the pressure to drop some when opening the faucet, so unless it is a noticeable difference, do not worry about it.

A high noticeable drop in pressure could be caused by a restriction in the piping someplace. In my case it was in the street main which cost the homeowner thousands to prove it was the cities fault. I hope they recouped that money from the city.

When you open the cold water faucet, the psi drops 20psi -30psi very quickly.

When you open the hot water faucet, the psi drops at a slower rate.

Is static water pressure and water pressure the same thing?

What should the pressure be if two showers are running at the same time?

Is it OK to pre-charge the expansion tank to 70psi?

Static pressure is when you rub the water against the carpeted floor and create st.... Just kidding:)

Static pressure is the water pressure when all faucets are closed and you are reading your normal standing water inlet pressure.
As apposed to running pressure, such as when you open a faucet while reading the gauge.

Unfortunately, I am not an engineer so I cannot tell you what the pressures should be, but if you have a static pressure of 70psi, I would think you should be able to keep a 50psi average when running one or two items. The more you run, the more it will go down depending on the inlet size of the pipe and distribution piping within the home.

For instance, in the example I gave in the last post, I had 110-115psi static pressure before the PRV.and my test gauge connected without the PRV in place. When we ran the hose, it went from 110 to 20psi and the water came out of the hose about 3 feet. If I had full port in the piping and had a static pressure of 110psi, I should have been able to go 15-20' with the spray from the hose. That was when I called in the water works and they agreed with me, but still said it was in our piping, which we replaced and still had the same problem. They eventually dug up their end of the line and found the problem.

If I keep the static pressure at 70psi, is it OK to pre-charge the expansion tank to 70psi?

Why does the water gauge drop about 25 - 30 psi when opening a cold faucet? Is that normal?

Why does it drop slowly when you open the hot side of the faucet?

Based on all the stats I have given, is everything OK with my prv?

OK, if you would have checked out that chart for sizing the expansion tanks as I posted back in post # 19, you would see that the maximum working pressure is 150psi and the tanks come normally pre-charged at 40psi, but are adjustable to job specifications. So, my answer to your question about pre-charging to 70psi is. yes you can. If the pressure is staying at 70psi constant now, adjust the tank pressure accordingly and all should be fine.

Piping designs and sizing will affect the way the water pressure will fluctuate in your pipes. So without me being present on the job I cannot give you an exact answer as to how low the water pressure should get when opening a hot or cold faucet.

Good luck

Now that I know what my pressure is and if I keep my pressure at 70psi, it seems that I am almost at the borderline for the ST-5 expansion tank based on the amtrol website you provided. My current expansion tank has similar characteristics as the ST-5. What are the benefits for me upgrading to the ST-8 under my conditions?

Will the ST-8 last longer than the ST-5 under my conditions?

Will my current ST-5 like expansion tank last longer when I change the pre-charge to 70psi as oppose to the default 40psi?

How much does the pre-charge psi play a factor under my conditions?