Does anything look wrong with the way the flues are installed below? Previously, the "horizontal" pipe was on a downward slope before the installer made it have more of an upward slope, but there's still a change in the slope to go back down before it connects to the other pipe. I heard that this made cause a CO leak.

Not a plumber, but I think you're basically asking for some back-draft in this configuration.

Not only do you not want the left water heater to vent into a downward slope, you don't want the right water heater to vent into an upward slope at the Y connection. I think you really want a Y connector like this:



My $.02, the workmanship is pretty shoddy, too.

I appreciate the response. Other than the flues, does anything else look shoddy?

The expansion tank plumbing looks clean enough, but I'm surprised they used galvanized iron instead of copper like literally every other water heater I've seen - even in homes with PEX. I think it technically OK to use galvanized plumbing for water supply, but not recommended depending on water chemistry.

Personally, I see that and wonder if the installer was an inexperienced plumber. Normally, they've have no problem sweating up some copper, but that seems to be an art that is disappearing.

At a minimum, I'd want brass or copper.

So is the risk that the galvanized steel could rust? Is it an issue with hard water? There is a water softener installed.

Do you have any references for how the flues should be installed?

XXXVII said:

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So is the risk that the galvanized steel could rust? Is it an issue with hard water? There is a water softener installed.

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Just a guess, but it's probably a bigger issue with a softener. Softeners usually add salt, which typically accelerate the corrosion relationship between water and iron in the pipe. Galvanized pipe just has a layer of zinc that sacrifices itself in this galvanic relationship. If it's accelerated, the zinc is depleted faster.

XXXVII said:

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Do you have any references for how the flues should be installed?

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Usually there is a lot of good information in the manual for your water heater. I bet you can find it on the Lowe's website for that model if you don't have a copy handy. Ultimately, this is informed by the National Fuel Gas Code (NFPA 54).

I pulled up the manual and found this.





I definitely don't have the proper slope on the left exhaust pipe, and the flue that exits the roof is not perfectly vertical. F me this is horrible.

Sorry man. You're probably OK if it's not perfectly vertical, but that's just another workmanship issue for me when I see it. Shoddy workmanship to me is always a good indicator of other issues.

One other thing you might look for - is there a shutoff valve on the supply side of each the water heaters? It's not a hard requirement, but definitely recommended. It doesn't look like there is in the pic.

I don't remember seeing any shut off valves. For additional context, this is a new construction home and the closing is supposed to be about a week away. Trying to determine my options for getting the builder to fix this using a plumber that actually knows what they're doing. Not sure the best path forward because I also have an interest rate lock in place that costs money every day the closing date gets delayed.

BenTheGoodAg said:

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I'm sorry you're dealing with that.

But geez that is a crap job for a new build - there's no reason for any of the above-mentioned issues. I'd be pissed if I was a builder and this guy was on my job.

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I am beyond pissed. I looked into your comment about galvanized steel being used for a water heater. This article explains all the issues with it.

https://homeapricot.com/can-i-use-galvanized-pipe-for-water-heater/

Dang. I meant water supply more generally speaking. I don't use any galv piping myself and wasn't aware there was a code issue with it on water heaters specifically, but it makes sense why it's not allowed.

Seems like you have multiple code issues to take back to your builder.

Out of curiosity, how do you know galvanized steel was used and not stainless steel? I read that stainless steel can be used in hot water applications.

Something to confirm with a plumber inspection?

XXXVII said:

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Out of curiosity, how do you know galvanized steel was used and not stainless steel? I read that stainless steel can be used in hot water applications.

Something to confirm with a plumber inspection?

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Well to be fair... I assumed. But go take a look at a big box store and try to buy stainless steel fittings (3/4" nipples, elbows, tees) - they don't carry them. You might find them at a plumbing supply house, but I bet the inventory is pretty slim. It's just not something that's typically used in residential - brass is the usual alternative for copper when you need threaded fittings for potable water.

You can tell the difference in SS and galv fittings in person pretty easily, but it may help to take a fitting with you for reference if you're not familiar with the finish.

I could totally be wrong, but I'd be shocked if it was stainless.

ETA - what you are probably reading about are the stainless steel flexible supply lines. Those are becoming more and more common over the old flexible copper supply lines.

Looking at some pics from our inspection, it looks like the supply lines are stainless steel flex hoses like this one.

https://www.lowes.com/pd/EASTMAN-24-in-1-In-in-FIP-Inlet-x-1-In-in-FIP-Outlet-Corrugated-Stainless-Steel-Water-Heater-Connector/1002939784

I think the only parts that could be galvanized steel are the pipes/fittings connecting the expansion tanks. These are on the cold water side, so I don't think it's necessarily a concern?

XXXVII said:

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I think the only parts that could be galvanized steel are the pipes/fittings connecting the expansion tanks. These are on the cold water side, so I don't think it's necessarily a concern?

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I didn't find an explicit code issue with it. I didn't look hard, but it could exist. Here's what the AO Smith manual says:



I'm sure they don't like the galvanic relationship that the iron will have with the water heater internals.

Galvanized steel is not iron though, right?

Here's a close up pic of how one of the expansion tanks was connected as well as one of the pressure release drain lines. Does that look like galvanized steel or stainless?



ETA: The manual says not to use anything other than copper or cpvc for the pressure relief drain. Also, it get's smaller in diameter when it connects to that stainless hose. So that's definitely two mistakes with the install of that drain line, right?

XXXVII said:

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Galvanized steel is not iron though, right?

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Technically, galvanized fittings (tees, elbows) are iron, and galvanized nipples are steel, but practically, they're the same in this application. Chemically, steel is basically iron with carbon added for strength, but they corrode similarly in galvanic relationships. I'm guessing they're different because of the manufacturing techniques (casting vs extrusion)?

Stainless steel also has iron, but it has chromium, which dramatically improves the corrosion performance

XXXVII said:

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Here's a close up pic of how one of the expansion tanks was connected as well as one of the pressure release drain lines. Does that look like galvanized steel or stainless?

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That sure looks like galvanized to me. Stainless has more of a luster. Could be the camera, but I don't think so.

XXXVII said:

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ETA: The manual says not to use anything other than copper or cpvc for the pressure relief drain. Also, it get's smaller in diameter when it connects to that stainless hose. So that's definitely two mistakes with the install of that drain line, right?

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I think you're right on the material, and it's probably for the same galvanic reasons. But I would say they're using the same trade size on the stainless line, so it's probably within the spirit of the requirement. Subjectively, you might get a different opinion from an inspector.

Talked with the builder's plumber and they said all those fittings on the expansion tank and T&P drain are galvanized steel. Said they use this for all their installations all over the neighborhood. Trying to figure out how much of an issue this really is. The builder is checking with their VP and plumber on the issue.

To me the galvanized pipe does not raise big issues but the vent stack looks like it was completed by Vandals. Also it looks like they may transition to pvc at the ceiling line which makes that spacer a joke. And if this POS is acceptable I would bet they don't meet the through roof specifications also.

How do you know the galvanized fittings are iron?

I do not think it is PVC at the roof termination. It continues as a metal chimney through the roof. That must be some type of white sleeve at that point.

You may have missed the response a few lines up about the difference in iron vs steel, but just check out the spec sheet for a few fittings online - they're called out as malleable iron (Home Depot - Elbow, Grainger - Elbow, Lowes - Tee). They even have some discussion in the Q&A on that link to the HD elbow. There are a few on Lowe's website that use the terms steel and iron interchangeably on the same part, but they're iron.

I see, thanks. I actually talked with their plumber, and he said the nipples where the water lines connect are galvanized steel which I'm not sure about, and that those fittings are not a concern.

At this point, I will probably close on the house and get an independent plumber to check things later. Too much uncertainty with everything and no time to figure it out. Their plumber is of course going to say it's fine.

According to eveyone I've talked to, the installation is up to code with the city, but they will work to get the flues installation corrected.

Here's a good reddit thread on the topic where someone brought up a similar issue.

https://reddit.com/r/Plumbing/s/RFOnGE6DWk

It's pretty mixed as far as it being ok, but several are saying brass should be used. There's also the question on whether or not that pipe should be the main support for the expansion tank.

ETA: Apparently it is up to code to use that galvanized pipe in my area, but it is a cost cutting measure from the builder. I can't say I can fight them on this before closing. I'll probably have to get my own plumber to replace the pipes with brass and also add support for the expansion tanks.