Dunebilly Dave

The new house heater was installed by a relatively large, local, family company that's been in business since 1947 and one of the two brothers (in his late 50s, so a seasoned vet) who currently own/operate the company, and three other guys came in and took the old behemoth out and installed it in one day. Yeah, the Rheem won't fit where it's got to go.

Neither of the water heaters are fan-assisted. That's what I had originally wanted because of it's high efficiency and the fact that it would vent right out the side wall, so no duct work at all. That Rheem sounds great! How do they do that; how can it recover so fast and still have lower operating cost than a 50gal? Or are they just comparing it with a really outdated 50gal? Reading the specs though, it's 9" taller than the 40gal we're going with now, so it might be a tad too tall. The 17" diameter would be great for using in the same spot as the house heater, though. But if it's a shorter horizontal run, I mean, it would practically be going right into the chimney if we put it in the same room with the house heater, we might be able to get away with that height. I'll have to take some measurements. Still think it may be just a bit too tall. Plummen, I haven't forgotten you. I'm having a technical issue with a photo, but I'm workin' on it. I can't thank all of you enough for your time & input.

Well, I really didn't come here to talk about demeanor, but, since it keeps coming up . . . I'm here because I'm taking it seriously. I'm in the process of making decisions. Y'all can't have known this, but, I've spent LITERALLY months trying to understand what forces are in play. I think it's almost as bad to throw money at something and blindly trust an unknown quantity with a truck and some tools as it is to DIY uninformed. So, whichever road I choose, I have no intention of traveling that path in ignorance. As far as my "proud" proclamation of ignorance, I remember a sensei once telling a student he knew "less than nothing;" he could not be taught because he didn't know that he didn't know. You have to recognize your ignorance before you can seek the tutelage of a master - it comes from a place of humility and respect, not pride. Someone asking for help is putting themselves in a vulnerable position, so there's no need to smack them down. As Mike's signature says "One Team, One Fight," we're (hopefully) all on the same side here. I have no interest in being cheap or cutting corners at the expense of ruining my home, or worse, killing my family. On the other hand, I'm also putting a child through college, so I'm not going to blindly write checks for unnecessary expenses. And IF I can DIY some portion of the job and save some portion of that $100/hr, I most certainly will. At the same time, I understand that, like a doctor, you often are not paying for what he does, but what he knows. And just for the record, Mike, I never asked for an apology, and none was ever necessary. My comments where simply meant as a little friendly chiding, as I hoped the use of the silly emoticons would demonstrate. WHEW! Now to the actual issue at hand. I'm psyched that appliances are more efficient now. Our house heater is just two years old, and professionally installed. The heater we're replacing is only six years old. In fact, our original replacement choice was a 50gal tall, but, it was too tall to give us the necessary run:rise ratio. So we had to settle for a much less efficient, more old-school 40gal short. So the replacement is almost identical to the model it's replacing. By my reading of G2427.10.14, G2427.7.4, and G2427.10.15 this thing never should have been where it is. It's funny, but my original instinct was to put it in the same room as the house heater. The chimney is in that room, so it would be an extremely short run. Space is kinda tight, though.

Bill, Hearthman, Marc, and Mike, THANK YOU! THANK YOU! THANK YOU! I'm very grateful for your valuable insights into this issue. I've been all over the web with these questions and all the answers have been bumbling and useless. It's refreshing to listen to folks who have accurate information and solid training. You guys are the best! You've given me a lot to digest. So, just to clear up a couple of issues, the entire run of both the house heater and the hot water heater are inside the envelope. The chimney is in the middle of the house. Just as Bill guessed, it's all in our conditioned downstairs (not a basement, as my late Father-in-Law always insisted). It's finished, with drop ceilings and flooring, heat and air con, etc. The system has been in place with both house heater and hot water heater sharing the masonry chimney for just shy of fifty years (my wife corrected me). Again, in all that time, there has been no corrosion of any of the single-wall vent. The house heater was just replaced two years ago by a company that's been in business since 1947, and they inspected the chimney and installed the new 6" single-wall from the heater and a new Y joint, as well as the mortared seal to the masonry chimney. I apologize for troubling all of you since I was told by no less than three "pros" (as well as the folks that sold me an assortment of type B) that the requirement was 10" beyond the walls of single-wall vent, which would be a total of 24". It makes much more sense that 6" all around, plus the 4" vent is correct, since it adds up to 16" spacing of the studs (though they're 16" on center so there's ostensibly 7/8" of pine stud on either side impinging on that space ... just thinking out loud). Thank you all again. I really wish there was some way I could repay you all. I guess the best way I can repay you is to make sure the job's done right and to code. You guys really are the best. Thanks!

Yup, you're right. I've actually "lurked" around this site and read some of Mike's posts. I was both amazed and very happy that it was hausdok who answered my post first. That's why I opened my reply with "thank you," and said that I appreciate the input and again offered my whole-hearted thanks. But in answering someone who's seeking advice, maybe not so much of the "stop complaining" and the "lame-brained." The student is already in a subordinate position; no need to rap him on the knuckles for being inquisitive.

First off, thank you for taking the time to read and respond to this post. I really do appreciate your input! Having said that: DAMN! [:-bigeyes That was harsh! NO MORE COFFEE FOR YOU - ONE YEAR!!! [] I'm not complaining about the cost, I'm just not made of money. If buying the B vent is pricey, then (with all due respect to the profession) hiring a skilled plumber to connect some Tinker-Toy snap-together B vent system at $100/hr, plus markup on the parts, is pricey-ER. Maybe to an HVAC pro making that $100/hr it's no big deal, but it's a small fortune for me. I'm only pulling down $17/hr, so it would cost me about two weeks' pay to get a pro to do it. It's not that it's beyond my abilities to do it - far from it. I'm just trying to understand the how and why of the situation so I don't screw it up - so to that end, I offer my whole-hearted thanks! Why is venting into a masonry chimney a bad idea? It's the way the home was built - professionally. Just for the record, it was a professional plumber and a professional city construction inspector who installed and passed the current run of 3" single-wall that only has about 4" of clearance on one side and 8" on the other side. Until I cut out the sheet rock all around it, it was passing through a hole in the sheet rock that only had about a half inch of clearance. So much for THOSE pros doing a better job. But the current run (that's been in place for thirty years) is single-wall all the way from both the house heater and the hot water heater. The gasses have never lost buoyancy in all that time - that is to say, there's been no condensation, corrosion, nor CO backing up into the house. I'm just trying to understand how adding a single 1' section of double-wall would screw up the buoyancy of the entire run? If Type B double-wall is a bad idea the way I was suggesting it be used, then what kind of solution (staying with single-wall vent all the way) would there be to protect the wood studs and sheet rock wall? I'm asking for a little insight, that's all. (Please be gentle)

I am replacing an existing run of 3" single-wall vent from my old gas water heater with 4" required by the new gas water heater. The old run passes thru a sheet rock wall, but somehow does not have the 10" of clearance required by code. Now that I'm replacing it, I need it to conform to code. I would like to use Type B where it runs thru the 6" deep sheet rock wall, since it only requires 1" of clearance. I should mention that the hot water heater's output joins up in a Y connection with the house heater's (gas/hot water) 6" single-wall vent about a foot before the whole thing enters the chimney. I don't want to do any major construction on the wall to create the desired clearance. I don't want to blow $200 on Type B for the whole run, including a really pricey 6"x4"x6" joint. I also would like to avoid having to pull out the existing mortared chimney joint, and the subsequent widening of the opening using double-wall would require, and then re-mortaring the joint. I only want to use the B vent where it passes thru the sheet rock. Trouble is, while it's OK to go FROM single-wall TO double-wall, it's not OK to go BACK INTO single-wall FROM B vent pipe. WHY? It makes no sense to me. I understand it's code. I understand it's easier to inspect. I understand that for some reason no one makes a transitional adapter FROM double-wall TO single-wall. I just don't understand the logic of it - the physics of it - the thermodynamics of it. What's the underlying reason for the code?