Water Heaters and Expansion Tanks

[caryamark]

Hello,

I am a DIYer and had a couple plumbing questions that are probably easy for you guys. First offf I have a 16 year old water heater and I don’t have any problems at all with it, but should there really be an expansion tank on it to be set up properly as well as to meet code if required. I have read that they are necessary for “closed systems” but I am not sure how to identify this based on the pipes entering my home, but I do completely understand what is meant by a “closed system”. I have attached a pic of what is entering my home in the basement The house was built in 1990 and never had an expansion tank on the first water heater.

Second, is it just wise to just replace a 16 year old water heater since I consider that old and isn’t it basically to the end of its life where there is a potential for a leak as well as I am sure it’s not as efficient as it once was with some sediment buildup. Thanks in advance for your help!!

 

[Reach4]

To determine if you have a closed system, connect a garden hose thread pressure gauge. Take a hot shower, turn off the water, and do not use more water. Immediately go to the gauge, and see how high it rises. Alternatively, take a time lapse movie of the gauge during the shower. It the water pressure goes up lets say 30 psi while the WH recovers, your system is closed. The water meter may have an internal check valve.

You can connect the gauge to a laundry tap or the drain valve of the WH.

Using no water includes not flushing the toilet.

 

[Sponsor]

 

[caryamark]

To determine if you have a closed system, connect a garden hose thread pressure gauge. Take a hot shower, turn off the water, and do not use more water. Immediately go to the gauge, and see how high it rises. Alternatively, take a time lapse movie of the gauge during the shower. It the water pressure goes up lets say 30 psi while the WH recovers, your system is closed. The water meter may have an internal check valve.

You can connect the gauge to a laundry tap or the drain valve of the WH.

Using no water includes not flushing the toilet.

Thanks for your help! Not that that sounds difficult, but isn’t there a way to just look at the incoming pipes I posted and tell?

 

[Sarg]

The picture of the water meter indicates you are on a municipal system and there very likely could be a one way "check valve" at the street connection. That would be a closed system.
Reach4 provides good guidance because you need to know what pressure is in your home system to know if there are "issues" causing the need for an expansion tank. If the heater has been functioning for 16 years without any system leaks I'd guess you do not have pressure issues. You could ask your DPW crew if there are check valves.
( With a well system the pressure tank acts as an expansion tank )

 

[LLigetfa]

Thanks for your help! Not that that sounds difficult, but isn’t there a way to just look at the incoming pipes I posted and tell?

No. A check valve could be built into a water meter with no visible clues. A tattle-tale pressure gauge would save having to constantly watch or record it. I am on a well and have a camera constantly recording the pressure.

There can be expansion with no obvious clues. A humidifier, RO filter, or even a toilet fill valve can bleed off excess pressure.

 

[Fitter30]

Relief valve trips at either 150 lbs / 210°
Expansion pressure in your case backs up thru the meter.
Even though the relief valve on the water heater isn't dripping or flowing water pressure over 80 lbs is considered hi normal is 60 lbs. A prv (pressure reducing valve) and expansion tank) would be the fix.

 

[caryamark]

The picture of the water meter indicates you are on a municipal system and there very likely could be a one way "check valve" at the street connection. That would be a closed system.
Reach4 provides good guidance because you need to know what pressure is in your home system to know if there are "issues" causing the need for an expansion tank. If the heater has been functioning for 16 years without any system leaks I'd guess you do not have pressure issues. You could ask your DPW crew if there are check valves.
( With a well system the pressure tank acts as an expansion tank )

View attachment 102350

 

[caryamark]

Thanks for your help also! Is is a good idea to just replace a 16 year old water heater before it leaks. I have drained it a lot over the years, but never put in a new rod that my understanding gets eaten away as a sacrificial metal.

 

[Reach4]

Thanks for your help! Not that that sounds difficult, but isn’t there a way to just look at the incoming pipes I posted and tell?

See the cut-away picture of https://www.neoperl.com/global/en/home/products/backflow-prevention/for-water-meters

Could you tell by looking if that meter has the check valve (white thing to the right)?

 

[caryamark]

The picture of the water meter indicates you are on a municipal system and there very likely could be a one way "check valve" at the street connection. That would be a closed system.
Reach4 provides good guidance because you need to know what pressure is in your home system to know if there are "issues" causing the need for an expansion tank. If the heater has been functioning for 16 years without any system leaks I'd guess you do not have pressure issues. You could ask your DPW crew if there are check valves.
( With a well system the pressure tank acts as an expansion tank )

View attachment 102350

See the cut-away picture of https://www.neoperl.com/global/en/home/products/backflow-prevention/for-water-meters

Could you tell by looking if that meter has the check valve (white thing to the right)?

 

[caryamark]

Well the “white” is internal, but here are closeup pics of both sides of it. Also, let’s say I have an “open system” as is, does plumbing code still require an expansion tank or does the code vary by area? Again, I know when the house was built there was no expansion tank on the original water heater, but would someone add a check valve or do something to make it a closed system without adding an expansion tank or indicating it needed to be added. I know that the white unit was added and the device on my exterior siding was disconnected where they use to read the meter and replaced a few years back.

 

[caryamark]

 

[caryamark]

Well I did the pressure check after taking a long shower and then watching the pressure gauge and no one was using any water to release any pressure and it looks good to me! The lower pressure readings in the pics were when I first got out of the shower and the other pic was after a long time where it stayed consistently the same. I did position the “tattle-tale” red indicator to record the highest pressure as it went up.

So can I absolutely assume this is an open system or are there just systems where they leak down to make you think they are?

Also I asked about whether it’s a good idea to replace a water heater that is 16 plus years old and no one answered. I guess maybe a better question is when they do leak are they usually small leaks? That is what I am concerned about. What do you guys usually see?

Thanks so much for all your help!!

Have a great holiday!

Cary

 

[Reach4]

So can I absolutely assume this is an open system or are there just systems where they leak down to make you think they are?

I think so.

Also I asked about whether it’s a good idea to replace a water heater that is 16 plus years old and no one answered.

While I think no for myself, professionals would say yes. Homeowner associations, especially in multi-unit buildings would stay yes.

Leaks are usually small for a while.

 

[Sarg]

Just my opinions > Your pressure tests demonstrate you do not have high pressure issues.

Most municipal systems are indeed "One way or closed". Call your town and get the phone number for your water department and ask them.

I would be making plans for a replacement heater if mine was 16 years in service. ( Actually I will be buying an exact replacement electric Rheem after the holidays for the unit I installed 4 years ago. WE like hot showers. )

But also know we are unusual in that we service our system every six months ... i.e. flush the pressure tank ... check the switch contacts ( we have a well ) replace the heater elements .... wet vac the sediment from the tank and inspect the anode rod ( which we have already replaced once after three years )

 

[caryamark]

Just my opinions > Your pressure tests demonstrate you do not have high pressure issues.

Most municipal systems are indeed "One way or closed". Call your town and get the phone number for your water department and ask them.

I would be making plans for a replacement heater if mine was 16 years in service. ( Actually I will be buying an exact replacement Rheem after the holidays for the unit I installed 4 years ago. WE like hot showers. )

I was thinking for some reason most municipalities might be closed, but I never had any problems at all. I know the city worked in my basement a while back when they changed the meter to one they can read remotely. Maybe when they saw NO expansion tank they didn’t convert it to “closed” as they would do to others. ???

 

[caryamark]

I think so.

While I think no for myself, professionals would say yes. Homeowner associations, especially in multi-unit buildings would stay yes.

Leaks are usually small for a while.

Thanks so much for your help! Aiways wondered if I needed a tank when I sweated in my new water heater myself, but of course there was not one there before, but I guess thinking like that can get you in trouble sometimes……

 

[Sarg]

I was thinking for some reason most municipalities might be closed, but I never had any problems at all. I know the city worked in my basement a while back when they changed the meter to one they can read remotely. Maybe when they saw NO expansion tank they didn’t convert it to “closed” as they would do to others. ???

Not likely at all. Their responsibility is to protect their system from contamination.
I recall that my father had no expansion tank for decades until the village upgraded their water system and caused higher pressures that then generated leaks. The cure was an expansion tank.

 

[Reach4]

I would be making plans for a replacement heater if mine was 16 years in service. ( Actually I will be buying an exact replacement electric Rheem after the holidays for the unit I installed 4 years ago. WE like hot showers. )

But also know we are unusual in that we service our system every six months ... i.e. flush the pressure tank ... check the switch contacts ( we have a well ) replace the heater elements .... wet vac the sediment from the tank and inspect the anode rod ( which we have already replaced once after three years )

Replacing WHs after 4 years is unusual. Is there a leak that triggers your replacing? Your well water must be corrosive.

 

[Sarg]

Replacing WHs after 4 years is unusual. Is there a leak that triggers your replacing? Your well water must be corrosive.

Our well water is indeed crappy. We have had occasions where the calcium deposits were actually up over the lower element rod. Hopefully our existing heater will last awhile ... but I will be getting the exact replacement ( $379 ) before they modify anything and just keep it available. We have a large pole barn for storage.