Plumber left me with no hot water!

[Clag]

Please help! I am in quite the conundrum. I was supposed to get a new gas tankless water heater installed today. The plumber came today and after removing my old tankless heater realized that the previous owners were venting heater and furnace through the same pipe, through the roof, like a “y”. I see online that this is not uncommon, but the plumber says that my issue is that the current setup is with a category 1 vent pipe, while the new heater requires a category 3 a d said it shouldn’t be vented with other appliances. He can’t vent it somewhere else because it’s in the crawl space and the only options would end up being near a door or window. So, I’m stuck trying to find a solution, while also now being without hot water because he couldn’t reinstall the old heater after breaking it apart to uninstall. He said this was due to difficulty removing it because of age. Now he says my options are getting an electric tankless heater, but that requires hiring an electrician to run conduit, etc., which also isn’t easy because of the way the crawl space is designed and will be costly. Especially with it being the weekend. As a last resort, I even looked around for a regular water heater, but there are none available locally to fit the crawl space and absolutely no where outside of the crawl space to put it. He also mentioned having the HVAC venting system restructured, which requires tearing down a wall, etc., and even more money. I want to believe that there has to be a way to install this thing with the current venting setup. Any suggestions or advice will be greatly appreciated. Thanks, Maria

 

[Jeff Handy]

Sounds fishy, get quotes or paid advice and suggestions from several other plumbers.
Meanwhile, wash in the sink with hot water from the stove, or at a friend’s or neighbor’s house, do laundry at a laundromat.

 

[Mitchell-DIY-Guy]

Unless I’m mistaken can’t you get a high efficiency condensing unit that vents with PVC? Surely that venting is pretty easy.

 

[Duckbutter]

The problem is that you absolutely cannot vent a natural (draft, gravity) vent with a positive pressure direct vent or power vent.

Fault for this falls on whomever installed it that way to begin with.

When the blower kicks on from the tankless it will overwhelm the heater's draft vent and push CO back into your home.

What you found online is likely connecting two natural vent fixtures to a single common vent, that's fine as long as the common vent is sized correctly.

If the tankless is in a crawlspace, he can potentially run it to the outside of the house depending on mfg specs for max vent length.

 

[Duckbutter]

Unless I’m mistaken can’t you get a high efficiency condensing unit that vents with PVC? Surely that venting is pretty easy.

Yeah, my state won't allow homeowners to install water heaters, it's true.

 

[Mitchell-DIY-Guy]

Yeah, my state won't allow homeowners to install water heaters, it's true.

Right. The homeowner wasn’t looking to do it herself. She had already hired a plumber. The standard vent on the old tankless was done wrong, we get that, and the old tankless was destroyed removing it. That’s weird but whatever. Replacing with a high efficiency unit gives more venting options as you don’t involve other appliances and you use inexpensive PVC.

 

[Duckbutter]

... Replacing with a high efficiency unit gives more venting options as you don’t involve other appliances and you use inexpensive PVC.

STD sched 40 PVC is no longer allowed for exhaust, intake only.

 

[Mitchell-DIY-Guy]

Depends on local code that would [stupidly might I add] take precedence over manufacturers guidelines. The attached are excerpts from the current Rheem condensing tankless, 95% efficient. You have under normal circumstances a lot more options with a through wall installation than a separate through roof or wall termination dealing with hot gas. Something like this would solve her problem.

Sometimes people don’t want to spend the money for a high efficiency unit. Venting a conventional unit with SS flue pipe can get costly. I spent over $500 on SS vent parts for an $1100 tankless some years back.

 

[JG plumbing]

He's right you can't use pvc on exhaust anymore. They do have a plastic that works though. It's a long story about why you can't and why everyone is afraid to put into the code and instructions that pvc doesn't work. Basically they messed up years ago, now they don't know how to fix it.

Your can walk to to a boiler or water heater that used pvc on the exhaust and tap it with channel locks and it cracks like an egg shell. It turns nasty yellow and crumbles.

Is what happens when you let companies police themselves. They say "oh yeah we've tested it, it works". Then it takes years before the results of a I'll thought it technique realizes itself.

 

[Twowaxhack]

That’s hilarious......” everyone is afraid to put it in the code “

Seriously, that’s hilarious.

 

[JG plumbing]

Basically the pvc was never rated for it. If you read the pvc limitations it can't take more than 140, but the boiler/water heater manufacturers somehow tried to say you can. People (who are dumb) took that to mean you can. Pvc manufacturers said no, we never said you could we don't know why you thought you could. The code shrugs and says, what do you want from me?

 

[JG plumbing]

That’s hilarious......” everyone is afraid to put it in the code “

Seriously, that’s hilarious.

Actually the code doesn't allow it. They hedge and say go with the manufacturer, but which one?

 

[Duckbutter]

....... Is what happens when you let companies police themselves. They say "oh yeah we've tested it, it works". Then it takes years before the results of a I'll thought it technique realizes itself.

Couldn't agree more, also seeing "refer to manufacturer" more and more often in code is scary.

My guess is corporate manufacturers making campaign donations to influence local regulation.

I had a situation where, despite a plumbing fixture being listed as an "approved product" with my state, turns out it was in violation, a minor detail was missed.

The local inspector wouldn't allow it, I appealed to the state board and they gave the homeowner an exemption, but they warned me to avoid the product (provided by the GC) until it was modified.

The head of the state board explained to me that manufacturers apply for approval, they sign a statement that they've checked for code compliance and the board takes them at their word....liability falls on the mfg at that point.

He told me the state doesn't have the resources to review hundreds of thousands of products.

Scary.

 

[Mitchell-DIY-Guy]

Nonsense! I had the same Schedule 40 PVC as a vent on my furnace (two of the actually) for 27 years. Ditto for the power vent water heaters; three of those in 27 years. Exposed to Michigan winters and summers. Was absolutely OK. 27 years old. NOT BRITTLE. If the manufacturer says OK, and local code adaption allows, it’s fine. Exhaust temp nowhere near 140 btw. Warm not hot, mostly water vapor.

Which manufacturer? The one whose appliance you’re installing!

 

[JG plumbing]

Furnace/ power vent are different things. They have a fan diluting the hot gas a lot more than a boiler /tankless.

Now you see some of the manufacturers switching to only allowing cpvc for the first 5 feet of the exhaust.

 

[JG plumbing]

Nonsense! I had the same Schedule 40 PVC as a vent on my furnace (two of the actually) for 27 years. Ditto for the power vent water heaters; three of those in 27 years. Exposed to Michigan winters and summers. Was absolutely OK. 27 years old. NOT BRITTLE. If the manufacturer says OK, and local code adaption allows, it’s fine. Exhaust temp nowhere near 140 btw. Warm not hot, mostly water vapor.

Which manufacturer? The one whose appliance you’re installing!

The post was not for a power vent or a furnace. We aren't taking about those. You can read about it or just make stuff up. You choose.

 

[JG plumbing]

Here's one of many things online and in books addressing this.

 

[RS]

I sure am glad that I don't have to depend on incompetent plumbers to do my plumbing! How big an electric water heater could you get in your crawl space? You could put a 15 or 20 gallon electric in the crawl space and probably get along just fine, tankless water heaters aren't all their cracked up to be! Small tank type can even be run on a heavy extension cord until proper wiring can be installed. You could even put 2 small tank type in series if you can't get a bigger one into the crawl space.

 

[Duckbutter]

Furnace/ power vent are different things. They have a fan diluting the hot gas a lot more than a boiler /tankless.

Now you see some of the manufacturers switching to only allowing cpvc for the first 5 feet of the exhaust.

True, this is why power-vented heaters have plastic blower housings, direct vented condensing units do not dilute exhaust.

 

[Twowaxhack]

Actually the code doesn't allow it. They hedge and say go with the manufacturer, but which one?

Dont ask me.....I’m not the code book thumper here...