Hot Water Heater is Leaking

FredoSP

Hello Forum!

I’m back to ask a series of questions about my gas hot water heater.

I currently have a 40 gallon, GAS fired, GE “Smart Water” heater, manufactured in August of 2007.

Everything has been fine until one afternoon I started to hear that annoying beep from my Zircon Leak Alert/Water Leak Detector. I go downstairs and notice a small amount of water underneath the long copper pipe that is used for the temperature and pressure relief value discharge.

I searched around on Google/YouTube and came across lots of information that told me to start by changing the T & P value. No need (yet) to call a plumber for a $17.00 part, easy swap in, swap out, just put pipe dope on the threads and make sure to bleed the air out of the system – easy enough. I purchased the same P & T value, Watts ¾” 100XL-4 M7 150 psi/ 210 F, 105,000 BTU/hr.
I will include pictures of my old nasty T & P valve that has a lot of calcium deposits on it. Based upon the age of the T & P valve I thought that was the issue.

Things were good (dry) for a couple of days and just today I notice water in the bottom “trough” that the hot water heater sits in. Going back to the Internet (again) some suggested the Thermal Expansion tank also be need to be changed because that could have been the original issue.

I plan on changing the Thermal Expansion tank this weekend, under $50.00. I guess I have to wait and see if that does the trick, but here are some of my questions going forward:

1. I used a tire pressure gauge on the Thermal Expansion tank (next to the hot water heater) and it was 75 psi. I thought that was a bit high – thoughts? I know they come pre-charged from the factory and you need to “match” your cold water pressure to that of the tank.

2. I purchased a Watts water pressure tester from Home Depot and tested the domestic cold water in three spots in the basement (I had gate valves to screw onto). All three read 80 psi, again that seemed a bit high to me – Is that too high?

3. Maybe the real issue in the incoming water pressure and I need a pressure regulator on the cold line for the potable water? I believe I already have a pressure regulator on the pipes just before the oil burner.

Any help is appreciated. I’m lucky that I can always shut off the ball valves and by pass the hot water heater in the event the tank really gives me an issue and I would still have hot water and heat.

Thank you in advance!
Fred
Long Island, NY

mattmia2

Are you sure the water is coming out of the relief valve? you could put a cup or pan under it to confirm.

The expansion tank should be set to 80 psig with no pressure on the system, with the gas to the water heater on pilot, the cold water off and a hot water faucet open to relieve pressure. If it holds pressure like that it is probably ok.

That tank is pretty old, are you sure it isn't leaking somewhere else?

FredoSP

mattmia2 said:

Are you sure the water is coming out of the relief valve? you could put a cup or pan under it to confirm.

It's funny that you mentioned that. After I wrote the post I went downstairs and put something directly underneath the copper pipe. I will respond to the post tomorrow morning and will let you know. I guess it's not uncommon for older water heaters to leak from the bottom?

mattmia2

they leak in all sorts of places but because of the outer jacket it usually comes out the bottom

12 years is pretty close to end of life, I wouldn't get too excited about trying to find some other leak at a connection rather than replace it if it isn't the expansion tank.

rick in Alaska

I will stick my finger in to the pipe to see if it is wet, and also stick a piece of toilet paper in it to see if it gets wet.
When you check your pressure tank, shut the valve off to it and open up the drain valve to relieve the pressure. If you need to add air to it, leave the drain valve open until you are done adding water.
Rick

SuperTech

Have you ever replaced the anode rod(s)? If not I would think that your tank is just about at the end of its expected lifespan.

Jamie Hall

And to go back to your 80 psi question, that is a bit high for domestic water, but I wouldn't be too concerned about it. Now, anyway...

FredoSP

Hi All,

Morning update: I just checked the hot water heater and there is no water at the bottom of the drain pan. I do have roughly 4-5 oz of water in the small pan that I put underneath the vertical copper pipe from the T & P valve. So I can say it's definitely leaking from the T & P valve.

I guess my next step is to change the thermal expansion tank this weekend. I will report back and let you know.

I have not replaced the anode rod(s) within the last 5-8 years. I have no idea if they were ever done. Would you suggest I do that after I sort out the leaking? I'm sure it's a fairly straightforward process to swap the rods in and out.

Thank you all for your help thus far. Give me a couple of days to get the expansion tank installed and I will report back.

pecmsg

FredoSP said:

Thank you all for your help thus far. Give me a couple of days to get the expansion tank installed and I will report back.

I highly recommend getting a hanger on that x-tank. that's a lot of weight on the T.

hot_rod

80 psi is on the high side of acceptable pressure, most toilets suggest 80 as the max, here is the plumbing code.
Most PRV you buy are preset to 45 psi.

Could be the incoming water spikes over 80 psi? Add a gauge that can capture high spikes for a few days.

The rods can be a bugger to get out. I used a 3 foot cheater on a 1" drive breaker bar to change mine out recently. There are some special torque multipliers the work

Gsmith

I've found using an impact wrench with a correct size impact socket is a good way to remove the anode rod.

mattmia2

It may do more harm than good at this point if the anode has never been changed. There is another thread that discusses this.

Is there already a pressure reducing valve? Why does the water heater need an expansion tank? The 80 psig could be a result of the failed or mi-adjusted expansion tank. What is the pressure if you let some water out and measure again?

STEVEusaPA

Water heater needs an expansion tank, especially if there is a PRV and/or backflow preventer on the domestic water supply.
Flowing water then shutting off a faucet causes pressure spikes, measured with a gauge with a dead hand (pictured by @hot_rod).
Also you get spikes from rapid closes devices as seen on dishwashers, washing machines, and sprinkler systems.

hot_rod

Plumbing codes do require a means to handle thermal expansion, under these conditions, could be a tank or relief device.

If it has a tank now, it's possible that a BFD is installed somewhere in the supply, could be in a meter yoke, out in a pit, at the incoming line, or a check in the PRV.

I think all tanks should include one, as the water provider could add a BFD someday.

FredoSP

hot_rod: That's the same pressure tester I purchased at Home Depot. I will hook it up and will watch the red needle to see if it records spikes past 80 psi.

The PRV I purchased said it was rated to 150 psi or 210 degrees F. I assumed that's the threshold of the spring to open and vent?
Watts 3/4" 100XL-4, that has the 4" probe.

mattmia2: Good suggestion, I will hold off and touching the anode rod.
The only pressure reducing valve I can see is on the set of copper pipes the go to the boiler, but I don't think these are for potable water and are for the hydronic heat (hot water baseboard). Here's a picture of it.



STEVEusaPA: I do have a backflow preventer on the cold water line, just after the supply enters the basement. I think it's been installed for over 4 years and is required by my local water district (also the annual inspection of $60.00).



I think my next step is to change the thermal expansion tank that's next to the hot water heater. I will report back.

FredoSP

pecmsg said:

I highly recommend getting a hanger on that x-tank. that's a lot of weight on the T.

I thought the tank was mounted incorrectly because on every picture I see, the 3/4" tank fitting is at the top and you can easily take a pressure reading from the bottom. Unfortunately mine is in the opposite direction. I don't know if that was from my grandfather or the plumber.

I did take a reading on the tank and it showed 75 psi. I guess that's measuring the air pressure in the tank behind the rubber diaphragm? If the diaphragm failed would't it fill up with water and then the air pressure read 0 psi?

Jamie Hall

No, if the diaphragm failed it would indeed fill up with water -- at full system pressure. That said, it is most likely that it has failed and is at least partly waterlogged. With the backflow preventer on the house supplym like you have, you must have a functioning expansion tank or you will get exactly what you are seeing.

Larry Weingarten

Hello, Two things: Get a pressure gauge that has a red pointer in it that shows maximum pressure seen. Screw it onto the heater's drain and come back and have a look after the heater has fired. That will let you know what thermal expansion has been up to. About the anode, having a look at it is the only sure way to know the internal condition of the tank, so I'd have a look.As long as some metal is left on the core wire, the anode rod is worth replacing with a magnesium one. It uses a 1-1/16" socket. Use a six point type.

Yours, Larry

FredoSP

Larry Weingarten said:

Hello, Two things: Get a pressure gauge that has a red pointer in it that shows maximum pressure seen. Screw it onto the heater's drain and come back and have a look after the heater has fired. That will let you know what thermal expansion has been up to. About the anode, having a look at it is the only sure way to know the internal condition of the tank, so I'd have a look.As long as some metal is left on the core wire, the anode rod is worth replacing with a magnesium one. It uses a 1-1/16" socket. Use a six point type.

Yours, Larry

Hi Larry,

I hooked up my Watts pressure tester last night. Static was pressure was 80 psi at 9:00 PM. When I checked the gauge this morning it looks like it peaked to 140 psi and, just like yesterday morning, there was water in the small pan I put underneath the T&P relief value.

I'm supposed to get the new thermal expansion tank this evening from UPS. I will install it and see if I have water tomorrow morning. I will report back.

STEVEusaPA

I would definitely put a pressure reducing valve on the incoming cold water line.

mattmia2

did you check the charge in the tank with the pressure relieved from the hot water system? It should be set to 80 psig with no pressure on the water side. It can leak out through the schrader or even through the membrane over time.

FredoSP

mattmia2 said:

did you check the charge in the tank with the pressure relieved from the hot water system? It should be set to 80 psig with no pressure on the water side. It can leak out through the schrader or even through the membrane over time.

Before I install the new tank I will charge it to the static water pressure of the house, 80 psi.

JUGHNE

If you add a pressure reducing valve for the entire house, (and you probably should as that 80+ PSI beats up the washer, dishwasher, ice maker and toilet valves) you should readjust accordingly.

FredoSP

Hi All,

Just an update: I installed the new tank and charged it to the water pressure of the house. I wrote the date of installation and psi charge on the back of the tank. I'll give it a good 48 hours to make sure I don't have any leaks from my T &P valve.

Edit: I forgot to add that I put pipe dope on the threads.

Thank you all for your help and I learned a lot too!

FredoSP

Silly question: Any special way to dispose of the old expansion tank or just toss it in the garbage. I can tell its probably half full of water.

SuperTech

Drill a hole in it or bust it open with a hammer and that will help it drain the remaining water. Then it's scrap metal.

STEVEusaPA

Wished the exp tank wasn't upside down and was supported to the ceiling joists.
Your flue pipe is wrong/doesn't meet code.

delta T

Adding to what @STEVEusaPA said, code (I'm going by the IPC 2018) dictates that you cannot have a valve between the thermal expansion tank and the water heater. Code also mandates supporting expansion tanks by means other than the piping, and installing pressure reducing valve for any water supply greater than 80 PSI to regulate to a max of 80 PSI.

hot_rod

At his point that 140 spike could be from the thermal expansion, or the incoming line pressure spikes.

It seems high for thermal expansion from 80- 140, especially if someone opened a tap along the way.

A good PRV would be a wise investment for pressure spikes and the reasons above. Everything in the piping path will be happier at 45- 60 psi.

rick in Alaska

delta T said:

Adding to what @STEVEusaPA said, code (I'm going by the IPC 2018) dictates that you cannot have a valve between the thermal expansion tank and the water heater. Code also mandates supporting expansion tanks by means other than the piping, and installing pressure reducing valve for any water supply greater than 80 PSI to regulate to a max of 80 PSI.

Just checking about the code there. I know you can't put a valve in front of a relief valve, but I think you can have one in front of an expansion tank. I know Watts makes an isolation, purge valve for these. So, is it wrong? Might have to make some future changes if so.
Rick

Shane_2

Just out of curiosity, what was the model number of the new expansion tank?

I am probably mistaken, but it looks like a hydronic tank to me in the picture. I thought the st-12 was tan.

FredoSP

STEVEusaPA said:

Wished the exp tank wasn't upside down and was supported to the ceiling joists.
Your flue pipe is wrong/doesn't meet code.

I understand what you're saying, but I've never had any issues with the it is, and it's probably been like that for 30 years plus.

Care to inform me what's wrong with the flue pipe?

FredoSP

rick in Alaska said:

delta T said:

Adding to what @STEVEusaPA said, code (I'm going by the IPC 2018) dictates that you cannot have a valve between the thermal expansion tank and the water heater. Code also mandates supporting expansion tanks by means other than the piping, and installing pressure reducing valve for any water supply greater than 80 PSI to regulate to a max of 80 PSI.

Just checking about the code there. I know you can't put a valve in front of a relief valve, but I think you can have one in front of an expansion tank. I know Watts makes an isolation, purge valve for these. So, is it wrong? Might have to make some future changes if so.
Rick

I understand it's probably bad practice. Someone could accidentally close the ball valve and yield the expansion tank useless.

FredoSP

Shane_2 said:

Just out of curiosity, what was the model number of the new expansion tank?

I am probably mistaken, but it looks like a hydronic tank to me in the picture. I thought the st-12 was tan.

I purchased the same exact tank that was previously there. A THERM-X-SPAN T-5 Expansion Tank, 2 gallon.

On the site where I purchased the tank from, someone asked the same question as you. My Therm-A-Span said it's made in the USA on the black lettering. I guess the longer warranty and a slightly higher price for the Therm-X-Trol. Both (Therm-X-Span and Therm-X-Trol) can be used for potable water. Here's what it said about my T-5

Designed for use in closed, potable hot water systems, Therm-X-Span accepts expanded water as system temperature rises. This hot water is returned to the system when demand occurs. A thermal expansion tank, like Therm-X-Span, is essential in a closed system to protect your water heater.


Q: What's the difference between Therm-X-Span and Therm-X-Trol?

A: Therm-X-Trol valves have a longer warranty (five years rather than one year) and are made in the United States.

FredoSP

hot_rod said:

At his point that 140 spike could be from the thermal expansion, or the incoming line pressure spikes.

It seems high for thermal expansion from 80- 140, especially if someone opened a tap along the way.

A good PRV would be a wise investment for pressure spikes and the reasons above. Everything in the piping path will be happier at 45- 60 psi.

No more spikes with the new tank. The red needle on my Watts pressure gauge has been reading 88-90 psi MAX. Static pressure is still 80 psi, unless we are using the shower, dishwasher, laundry machine, etc.

STEVEusaPA

FredoSP said:

...Care to inform me what's wrong with the flue pipe?...

You need straight flue pipe off the draft hood (12” min I think). You can’t have an elbow on the draft hood.

SuperTech

> @STEVEusaPA said:
> (Quote)
> You need straight flue pipe off the draft hood (12” min I think). You can’t have an elbow on the draft hood.

I would also suggest adding some spill switches to the draft hood. Code requirements in my area call for them. They may not be necessary, but additional safety devices never hurt.

STEVEusaPA

I wouldn't even use the draft hood. Just dual acting baro, and spill switch.

SuperTech

I like the idea of just using a dual acting barometric damper. Better control on the draft. I almost never see any gas water heaters installed like that, only boilers.

FredoSP

Thank you all for your suggestions. I will keep a running list so when the 13 year old hot water heater finally goes, I can mention it to the plumber upon install of the new water heater.

I had another question. I've always wondered what this was on my cold water pipe that goes to my sprinkler system. I believe it to be a check valve, but I'm not sure.



Wider view for reference

pecmsg

You need a back flow protector on sprinkler line!