Electric water heater installation - certain code requirements

[Stephen Tashiro]

I'm curious about why plumbing codes (in locations different than mine) have some of the following requirements.

1. Accordion type flexible water line connections are not allowed. (As Steve Lavimoniere says in https://www.youtube.com/watch?v=UoMzdqO5AZU ) I don't know if this also applies to the pressure relief drain.

2. A vacuum breaker must be installed on the cold water line. (He says it keeps the tank from collapsing should the fire department start using a lot of water from the main iine - only a concern in big cities?)

3. A top-mounted factory installed "short stem" pressure relief valve must be replaced by a "long stem" pressure relief valve.

From other videos:

4. A service disconnect box is required. Romex cannot be used to connect the disconnect box to the heater. (In my location, the pros use a cable that resembles an appliance cord for a dryer or stove.)

[Jim Koepke]

What is your source for the specifications of these codes?

The code may be the pressure relief valve needs to reach in to the top 6" of the water heater. Is that what you mean by "long stem" versus "short stem"?

Vacuum breakers are usually required on irrigation lines.

Accordion lines may be subject to failure.

jtk

[Bill Dufour]

In California accordian gas lines are required. Not sure about water lines but they sell a lot of them at the Borgs in town.
The service disconnect viable from the tool itself is required in a shop. Romex has to be supported within 12" of the box so a service whip seems logical.
California requires water heater to be strapped down so they do not fall over and break off gas, electric and water lines in a quake. That should be required in NM?
Bil lD

[Edward Dyas]

I'm curious about why plumbing codes (in locations different than mine) have some of the following requirements.

1. Accordion type flexible water line connections are not allowed. (As Steve Lavimoniere says in https://www.youtube.com/watch?v=UoMzdqO5AZU ) I don't know if this also applies to the pressure relief drain.

2. A vacuum breaker must be installed on the cold water line. (He says it keeps the tank from collapsing should the fire department start using a lot of water from the main iine - only a concern in big cities?)

3. A top-mounted factory installed "short stem" pressure relief valve must be replaced by a "long stem" pressure relief valve.

From other videos:

4. A service disconnect box is required. Romex cannot be used to connect the disconnect box to the heater. (In my location, the pros use a cable that resembles an appliance cord for a dryer or stove.)Codes are just someone's opinion. You will find some of them that don't make any sense. It's also why every town has different codes. Lots of different opinions.

[Tom M King]

It's been a long time since I remember seeing a water heater with a top-mounted pressure relief valve. They are easily converted to a "long stem" by soldering in copper pipe.

[Tom M King]

Thinking about the "accordian" type flex hoses, I'm not even sure the ones they're talking about are even still on the market. The first ones they came out with had built-in compression washers in the ends. If you tightened them too tight they would leak, but not right away, and were very critical to have just the right torque.

I've had nothing but good luck with the newer stainless steel braid covered hoses with ends that look like stainless female garden hose ends. Those have some sort of high temperature washers (guessing), that look like regular garden hose washers, that are very forgiving with tightening pressure.

[Mark Bolton]

The vacuum breaker applies to more than just a city water line issue. Technically depending on the location of your water heater and a myriad of other factors in your plumbing system, just draining the lines could pull enough vacuum to cause a tank issue but it would be EXTREMELY rare. But thats what the code is for. Its to cover the extreme rare instance. No different than vacuum breaker requirements on outside silcocks for the issues of cross contamination. You toss your garden hose in your kiddie pool and your 1 year old is splashing around in their peeing and crapping in their diaper and the watersupply (city or otherwise) has an issue and you wind up in a back flow/siphon situation and you contaminate your potable water supply lines with urine and fecal kiddie pool water. Same issue with drain loops on dishwashers, air gaps on washing machine drains. When I apprenticed in the 80's you were not allowed to use a hooked washing machine drain that sat in the drain line. There was a metal clamp that held an air gap between the washing machine hose and the drain line so there was zero chance of waste water getting into the washer and somehow getting into the potable water supply. How that could ever happen I do not know.

Filling your dishwasher with a filthy load of sink water is easy if you didnt install a high loop on the drain line though most dishwashers now incorporate that loop into the side of the machine from the factory.

6" Temp and pressure relief valves not being allowed an must be swapped for 8" has been common in many places for 40 years because the thought is the edge of the tank can be cool enough to not cause the relief to trip. If you want to learn about the nightmare of an exploding water heater start doing some research. The latent energy in a water heater with super heated water and no relief valve or one that was plugged because it is weeping is mind blowing. Imagine 40 gallons of water (9240cu" or 5.34cu') instantly expanding 1728 times its volume in an instant when that super heated water flashed to steam when the tank bursts. That 5.34 cu' of water instantly becomes 9240cu' of steam. Its a bomb. In trade school incidents were commonly referenced where entre wings of schools and commercial buildings were blown off the face of the earth by a water heater with no, or a plugged, relief.

Relief valve drain lines being rigidly extended to within 6" of the floor is so that if anyone is working on or servicing the heater, or anyone is close to the heater, when the relief trips they cant be under it.

It goes on and on, pressure balanced/anti scald shower valves, and so on.

The code can seem a little kooky at times but at its core it is simply a minimum standard and based on some crazy stuff happening that no one ever thought possible.

[Tom M King]

Great post Mark!

[Jim Koepke]

Imagine 40 gallons of water (9240cu" or 5.34cu') instantly expanding 1728 times its volume in an instant when that super heated water flashed to steam when the tank bursts. That 5.34 cu' of water instantly becomes 9240cu' of steam. Its a bomb. In trade school incidents were commonly referenced where entre wings of schools and commercial buildings were blown off the face of the earth by a water heater with no, or a plugged, relief.

That must be the inspiration for the insurance commercial with the flying water heater.

jtk

[Mark Bolton]

That must be the inspiration for the insurance commercial with the flying water heater.

jtk

Itd be nice if they flew through the roof like a rocket lol. But it's more like an improvised explosive device that goes in all directions coupled with superheated scalding steam.

[Derek Meyer]

There was a Mythbusters episode years ago that explored the myth of the exploding water heater. Adam and Jamie built a small minimum code-compliant house and placed the water heater inside, disabled the safety mechanisms on the water heater and then let the pressure build. When it burst, the water shot through the roof of the house like a rocket, flying several hundred feet in the air, and the house collapsed into a pile. It was one of my favorite viewing moments ever on the show. And I immediately went down and checked my water heater to verify the pressure relief valve and drain were in good working order.

[Andrew Seemann]

A couple dozen years ago in one of the St Paul suburbs a water heater exploded. I remember it from the news story. It shot through the roof and knocked the house of its foundation. They reference the incident in the Mythbusters episode.

https://www.upi.com/Archives/1993/06/02/Water-heater-rockets-through-roof/4054738993600/

[John Goodin]

According to the IRC an electrical disconnect is required. This is usually a simple switch mounted nearby. From what I understand it is required so the power can be disconnected easily for any maintenance and repairs.

I have not heard the corrugated lines are prohibited so it may be a local or statewide issue. While the home improvement centers sell them I would opt for the woven stainless steel hoses, similar to ones used for washers, for a few extra dollars. I once helped a friend’s dad rebuild his place after a corrugated copper line developed a pin hole leak. There was so much water that his walnut floors popped up and the side yard flooded.

[Mark Bolton]

When it burst, the water shot through the roof of the house like a rocket, flying several hundred feet in the air, and the house collapsed into a pile.

Id imagine most light residential tanks would fail at top or bottom where the pressed ends are welded on for the rocket effect. If I remember correctly the school incident was in TX and was a large commercial stone lined heater. Either way, its a bad day.

[Ole Anderson]

I replaced a water heater using the stainless flex hoses with garden hose type connections on the hot water side galvanized steel pipe connection. I had a terrible time getting it to seal. The cold water side was fed by a copper pipe so I used a shark bite (on one end) style stainless flex hose. Worked much better. By the way, they aren't really that flexible, they need to be almost the exact length.

[Mark Bolton]

I have now been involved in three failures of those SS water heater flex connectors one of which was at my SO's house and didnt flood the basement but made quite a mess and literally soaked a 200 amp main panel as luck would have it the leak happened with a pretty much direct shot at the panel 15' away.

I personally would never install any of those flex lines in my home anywhere. When one fails you will see that the inner poly tube is not very substantial (hence the outer s.s. braid) and all three of these the inner tube had pretty much turned to a soft gooey plastic. My guess is chlorine in the city water supply but who knows.

Ive said it before, I dont even use the flex connectors on toilets and sinks. Soft copper is the only way to go for me.

[Perry Hilbert Jr]

I have replaced 4 water heaters in 25 years in buildings we owned. Always used the copper accordian connectors. Except the last two when we connected pex tubing to 8 inch metal extensions on top the tanks. Never had a leak there. Had leaks in old copper pipes from hard water corroding the pipes after 40 years. Every one of those buildings had a wall switch within two feet. The last unit came with an elbow and three foot pipe that directed water from the relief valve onto the floor.

[Mark Bolton]

Had leaks in old copper pipes from hard water corroding the pipes after 40 years

There's your money shot.

[Stephen Tashiro]

In the typical installation diagram for a Rheem electric water heater, I find another unfamiliar recommendation - the 6 inch "heat trap". What's the idea behind a heat trap?420467

[Bill Dufour]

Heat trap prevents thermosyphoning since hot water rises, it does not go down unless there is pressure pushing it out. My last water heater I installed check valves on top of the tank to eliminate thermosyphon effects.
Old Yanmar tractors had no water pumps just let the hot water flow to the top of the tall radiator and fall down the radiator as it cooled to be drawn into the bottom of the engine.
Bil lD.

[Stephen Tashiro]

Looking at the Rheem water heater I have, it appears to have "heat trap nipples" already installed. https://www.homedepot.com/p/Everbilt-Dielectric-Nipple-Heat-Trap-15009/205680991 Those plastic inserts could easily be mistaken for temporary caps to keep debris out of the pipes.

[Bill Dufour]

There may also be dielectric unions on the heater. Not sure how but they are supposed to prevent water pipe electrolytic corrosion. They do mean the water pipe is no longer connected to ground. Some people put jumper wires around them which defeats the purpose.
Bil lD

[Stephen Tashiro]

There may also be dielectric unions on the heater.

On this particular water heater, there are only the nipples. No union fittings were included. However, it's interesting to hear about dielectric unions. The accessory plumbing for water heaters is turning out to be a complicated topic!

Another technicality is that some places require that there be at least 18 inches of metal pipe between the cold and hot water heater connections and any plastic pipe.

[Jim Koepke]

The accessory plumbing for water heaters is turning out to be a complicated topic!

In my previous residence, in a different state, a water heater installation required an inspection. This is only one of the reasons we decided to have it done by a professional.

jtk

[Rollie Meyers]

I'm curious about why plumbing codes (in locations different than mine) have some of the following requirements.

1. Accordion type flexible water line connections are not allowed. (As Steve Lavimoniere says in https://www.youtube.com/watch?v=UoMzdqO5AZU ) I don't know if this also applies to the pressure relief drain.

2. A vacuum breaker must be installed on the cold water line. (He says it keeps the tank from collapsing should the fire department start using a lot of water from the main iine - only a concern in big cities?)

3. A top-mounted factory installed "short stem" pressure relief valve must be replaced by a "long stem" pressure relief valve.

From other videos:

4. A service disconnect box is required. Romex cannot be used to connect the disconnect box to the heater. (In my location, the pros use a cable that resembles an appliance cord for a dryer or stove.)

A "service disconnect" is what disconnects the service entrance conductors , a appliance requires a disconnect, and it would a very rare situation that they are service entrance conductors.

[Mike Cutler]

I have now been involved in three failures of those SS water heater flex connectors one of which was at my SO's house and didnt flood the basement but made quite a mess and literally soaked a 200 amp main panel as luck would have it the leak happened with a pretty much direct shot at the panel 15' away.

I personally would never install any of those flex lines in my home anywhere. When one fails you will see that the inner poly tube is not very substantial (hence the outer s.s. braid) and all three of these the inner tube had pretty much turned to a soft gooey plastic. My guess is chlorine in the city water supply but who knows.

Ive said it before, I dont even use the flex connectors on toilets and sinks. Soft copper is the only way to go for me.

Mark
Do you happen to remember which brand you used, and what the time interval to failure was? I installed two of them over a decade ago on our water heater, and to date they have been fine. Of course, everything is fine, until it isn't.:eek:
Every sink in my house, and both toilets have flexible, braided, stainless hose going to it. I did have one failure, but it was an OEM, Grohe hose. Luckily it came after the valve. It had gotten kinked somehow or the other.

Stephen
Don't drive your self crazy installing an electric water heater. Mimic what was there, and you should be fine unless you're going to a different style system.
The difference for the codes is geographic location.
Mine has all the check valves, shutoffs, and anti siphon devices installed, and I don't need any of them, except for the check valves. I'm on a well, not city water. It is impossible for me to back pressure, and contaminate the city water system. The closest city water pipe to me is 3 miles away. But, my water heater had to have all of those features. I also have anti siphon hose bibs installed, which I don't need.

[Mark Bolton]

Do you happen to remember which brand you used, and what the time interval to failure was?

No idea on either as I never installed the original flex lines and never bothered to check the brand on the failed connectors. As you say, they are fine til' they are not which is another of my big problems with these flex lines. Unlike copper, or even threaded, they give you virtually no warning of pending failure. A copper or threaded connection will be tapping you on the shoulder regularly for a long period of time before it ever completely lets loose. A drip, a bit of corrosion visible, and so on. Not so with these. Your lucky if they fail with a drip or two prior to a hole big enough for a steady spray/stream of a leak.

I too have lamented the move by the manufacturers to install them factory connected to valve bodies all in an attempt to ease the DIY movement. I have less of an issue with them on the low pressure side (valve body to a spout) but under constant pressure they are a bad choice for me but you have no option with the factory installed stuff.

The odd part is that all of them state clearly that they are not to be installed in concealed locations where they can not be regularly inspected. #1 this makes no sense because they will rarely show signs of imminent failure visually, and #2 they are selling them for dishwasher and sink connection that are impossible to see, or rarely seen.


I'm on a well, not city water. It is impossible for me to back pressure, and contaminate the city water system. The closest city water pipe to me is 3 miles away. But, my water heater had to have all of those features. I also have anti siphon hose bibs installed, which I don't need.

This isnt actually true. While you of course cant contaminate a city water supply, the potential is most definitely there (although its about as good as a lottery ticket) to contaminate your own. The back flow/vacuum breaker/anti-siphon devices apply to public and private water supplies equally. Any number of issues could cause you a back flow situation. The check/foot valve on your well could fail and the column of water in the well would drop back into the well pulling a siphon on your entire home. The line between the well and the home, or the drop in the casing could fail and cause the same condition. The same could happen with maintenance. Ive done many homes with wells hundreds of feet deep and that are far over a hillside well below the elevation of the home. If any of those happened there would be a column of water easily capable of creating a siphon or collapsing a tank and worse siphoning nasty water back into your potable water piping.

Would it kill you? Who knows. Put you on the pot for a few days? Who knows. Ever actually happen? Who knows. But all this stuff just like car insurance, is there for the rare occasion or hopefully never.