Venting requirements for gas HWH?

[Barrybpdx]

Can someone point me to a website or something that explains in relatively simple terms the requirements for venting a gas HWH? or does it vary somewhat from unit to unit?
I'm just trying to figure out if I can replace my electric unit with gas. it's right on a basement wall perp to the joists so up-and-out would work great. but I do have a window and door that are possibly too close.
I read a few posts here that were pretty down on power venting. Is that how the pros here feel, like power venting should be avoided? To the extent of sticking w/ electric?

 

[GoTanklessToday]

You don't want a power vent unless that's the only option. We prefer direct vents, (State/AOSmith), but if you are below grade that won't work. If you are going to use a standard vent heater and you can get the vent pipe up and through the roof, then that's the way to go. B-vent (double wall) can be ran out and up the exterior of the home, but it too needs to penetrate the roofline or eave. If you go that route, you should install a tee at the lowest exterior joint to allow the condensation to drip out and not corrode the pipe.

Of course, tankless may be the best option yet, but that depends on other things. If you are in Portland, you can call Stan The Hot Water Man. Their crew is top notch. Ask for Brent.

 

[Sponsor]

 

[Randyj]

What kind of angle does code require when exiting a HW vent thru a wall? I've seldom dealt with gas HW heaters and was just wondering the proper method(s) of running exhaust venting. It is something that I really need to know.

 

[GoTanklessToday]

The best method is to use a direct vent heater when you have to vent through a wall. But if you are running B vent through a outside wall, just make sure you have a 1 inch clearance to any combustible surface, and at least a 1/4 inch per ft rise. The first fitting outside should be a tee with a bird screen on the bottom (I usually put a 1 foot section of b vent into that tee pointing down). Im not sure if that would be required in Phoenix or areas where it doesnt get cold, but here in Seattle, it has to be done or the condensation will eat the pipe up in no time. Once you are on the exterior, then you use unistrut or some type of clamps that will secure the venting to the exterior and maintain the clearance you desire.

I say again though that this is not the ideal method. The best approach is to go up and through the roof, or use the proper style heater for the situation.

 

[Master Plumber Mark]

what's the matter with a power vent???

I know that this will start a huge debate.....

but what is the matter with a Brad White Power vent??

They are by far superior to the Smith and State brands....


If you can get a 4 inch double wall metal vent out through your roof
from the basement ...all the better....

just put in a normal gas water heater.....

If you cant swing it install a Brad white power vent....
and just stub it out of the house somewhere up to 60 feet away in 3 inch PVC pipe
as long as it is not under a bedroom window it will work fine
for many years to come....




with either one you will save money over the electric heater



but either way

stay away from the tankless heaters..

(there , now I said it).

 

[Randyj]

Tankless... I don't think just condensation is a concern. I'm in Alabama and have seen oodles of rusted out elbows on gas vents. I think the big problem is that rain water gets in them and usually that's because the hat rusts out and blows off allowing rain water to get in.

 

[Gary Swart]

Yeah, just what do you see as being wrong with a power vent. My research shows for a direct vent you need an 8" hole while a power vent only need 3". I've been using a Richmond power vent for years and find it quite satisfactory. When mine was new, the require a 4" PVC or ABS vent and had a few more restrictions on distance and elbows than the new ones. I'd sure be interested to know why you think direct vent is superior to power vent.

 

[Randyj]

Gary... I know there's pro's and con's to virtually everything. One thing I can think of as a possible negative for power vents is that it carries away heat that is being paid for and also consumes power ...both robbing a little of the efficiency. HOWEVER, power vents get rid of spill over carbon monoxide and other gases and byproducts of burned fuel and to me is a big time safety feature. I think power vents are great in certain applications and in other applications they're just an unnecessary add on expense. I did have one guy to tell me that I needed a power vented (tankless) HW heater for my radiant floor heat and that a (tankless) ventless system was not acceptable.... I don't have a clue why he came to this conclusion.

 

[Master Plumber Mark]

power vent --pros and cons

I have not even seen a direct vent heater in years.....

I would not even know what one looks like anymore....

That usually tells you something about their popularity ...

Where are they still popular anyway?????

The only down side I see on the power vents is future
breakdowns... but I have not had any with theBrad White units in years.

----------------------------------------------------------------------------
I had a call today from a lady with a 1995 SMITH power shot....

Told her that even though it was not leaking she was in the market

for a new heater..... for $1175.00

It had worked flawlessley since 1995......they never touched it.

I think the Brad White 50 gal power vent is going in on Monday...



as far as future break downs......the POWER VENT for $1200

is much much cheaper than an Tankless heater for 2500-4500

and I can guarantee that it will breakdown long before the power vent will...

 

[Gary Swart]

I found information about direct vent with a Google search, but about all I could really glean from it was that the direct vent requires an 8" hole with a short distance from the tank to the outlet and it requires no electricity (BFD) The power vent can have up to 60 feet of 3" PVC so it is not nearly so critically on installation location, and it does require a 120 VAC power outlet for the fan. I would not even consider a tankless unit, but I think they have the same vent options.

 

[Molo]

Gary... I know there's pro's and con's to virtually everything. One thing I can think of as a possible negative for power vents is that it carries away heat that is being paid for and also consumes power ...both robbing a little of the efficiency. HOWEVER, power vents get rid of spill over carbon monoxide and other gases and byproducts of burned fuel and to me is a big time safety feature. I think power vents are great in certain applications and in other applications they're just an unnecessary add on expense. I did have one guy to tell me that I needed a power vented (tankless) HW heater for my radiant floor heat and that a (tankless) ventless system was not acceptable.... I don't have a clue why he came to this conclusion.

Do you have a tankless ventless gas hot water heater? I didn't even know they made these...

Molo

 

[Molo]

I know that this will start a huge debate.....

but what is the matter with a Brad White Power vent??

They are by far superior to the Smith and State brands....


If you can get a 4 inch double wall metal vent out through your roof
from the basement ...all the better....

just put in a normal gas water heater.....

If you cant swing it install a Brad white power vent....
and just stub it out of the house somewhere up to 60 feet away in 3 inch PVC pipe
as long as it is not under a bedroom window it will work fine
for many years to come....




with either one you will save money over the electric heater



but either way

stay away from the tankless heaters..

(there , now I said it).

I preface my statement by professing nearly compete ignorance on venting methods. Why 4" double wall Mark? Is that required? I ask because the gas tanks I have seen take a 3" pipe off the tank. Is 3" double wall an actual 4" measurement?

Just learning
Molo

 

[GoTanklessToday]

Here in Seattle, direct vents are VERY popular. So are tankless systems, which are far superior to tanks in 99% of the cases. We install 40+ tankless heaters a month. I can concede that they may not be the best choice in all parts of the counrty due to the quality of the water. We have good water here in Washington. We don't need to flush our water heaters here (as a rule) like you need to in other areas of the country. For those customers who aren't into tankless systems here, we would always use a DV before a power vent. The power vent replacement parts are expensive. There are few parts on a DV, and those that can fail are common.

Sure, we use power vents too. They are always our last resort though. We like the Rheem power vent, and it is the most widely used in the Seattle area. BW is great too, just not used as much here. And I don't mean to imply that if you don't do it our way, you are doing it wrong. Different areas of the country do things differently. Heck, different companies do it differently, as do different plumbers.

 

[Cass]

The only benifit I can see using a DV heater over a standard is the heater not using heated or cooled air from the home to heat the water with and what ever energy savings that would amount to..

 

[Master Plumber Mark]

4 inch double wall over 3

the 4 inch double wall is the best way if you got to run one

reasons are if you ever want to ever increase the size of the heater to 75 gal you can.....

it is less restrictive and will get all of the carbon monoxide....

the cost is really not that much more to go a little bigger

and In this city they want to see 4 inch vent if a permit is taken out to do this work....



a question for the GO TANKLESS guy

what kind of tankless heaters are you installig in Seattle???

I just went to a RHEEM school for tankless and was not impressed
with the "glorified rice cookers " that they were selling...

the copper heat exchangers looked pretty scarey to me.....it was not L copper
it was not K copper...it was something of an odd ball configuration ...

and of course it would not fly too well around here...

So everyone in the class was very leerey of the heat exchangers made in
Japan, and the Technology was far more coplicated than a normal
power vent......


Troubleshooting one of those little jeweles made everyone pretty skeptical......

But I guess it would keep you in business if you were one of the
only fellows in Seattle who could fix it today.......

 

[Dunbar Plumbing]

I've seen only one direct vent in my area. I always ask the "color" of the pipe coming out of the center of the water heater so I don't get called out to a power vent call. (Pratically the only simple knowledge that people understand in relation to their water heater. Some don't even know if it is gas or electric.)


If they say "white pipe" then I know to shoot the call to another company for repair.


When I asked about this particular heater, the customer stated it was gray, meaning galvanized/metal as he explained.


This water heater was sitting in a garage, on the floor, not a FVIR model, direct vented right out of the adjacent wall. The final outcome was there was a control module that was defective that repaired the unit.

On top of this.....the homeowner or some hack tee'd off the 1/2" gas line feeding this unit to install a wall hung gas space heater. The room is significantly small, spray paint/gasoline, lawnmowers are in this same room and all I want to do is get out before the place blows up and I'm to blame for just being there.

I advised him of the numerous potential dangers........he shirked it all off like it was nothing.


One customer I'll definitely say no to in regards to any future work in relation to that garage application.

You know he'd throw caution to the wind about the charges incurred to put a stand in and direct the T&P to the outside. All 1/2" inside that garage with no larger pipe in sight.

 

[Jimbo]

Each unit comes with specific installation instructions, but if you want a reference to read up on, get the National Fuel Gas Code book, from the NFPA. It is not expensive, and has all the info.

Some of the things you have to understand are types of flue ( single wall, double wall, masonry, etc) , combustion air requirements, as pipe size, etc.

 

[GoTanklessToday]

A 75000 btu heater wont always work on a 4 inch vent. It depends on the overall vent height, and the amount of horizontal.


We install all the major brands. Rinnai, Paloma ( the Rheem you saw), Noritz, Takagi, Bosch. We favor Rinnai on inside mounts since they are direct vent models and their vent is zero clearance. We favor Noritz or Paloma for outdoor mounts. Paloma had the best freeze protection of them all, while Noritz has a way nicer pipe cover kit. Is one better than the other? Not really. There are no bad ones in that group. Only ones that will be a better choice for the customer.


Your comments are very typical of plumbers around the USA. 4 years ago, I was right there with you. I was installing tankless heaters in Portland 20 years ago, and I remember how they sucked big time. I put 3 in one week, and took all three back out the next week. So trust me... I was not a proponent of tankless at all. But things changed about 4 years ago. The Japanese companies started marketing their heaters here in the USA. Before then, the models available were the heaters used primarily in Europe, where they tend to use them more "point of use". It wasn't working to try to use one of those modesl "whole house". It's the Japanese who mastered the tankless heater. And as for a glorified rice cooker? You may want to do some research before you jump to that conclusion. These heaters are not new, nor is the technology. Noritz has been making and selling tankless water heaters for over 50 years. They typically last 25 years, plus all the components are replaceable individually. When the heat exchanger leaks, install a new one. The tankless heater is the last heater a home needs. When the tank ruptures, install a new one.

Why don't the Japanese models come with a better warranty? I have asked this question to the Vice President of Noritz. The simple answer is "they dont need it". If they were to factor in reserves for warranty, the prices would be even higher.

I'm personally glad that most of our competitors aren't on the "tankless train" yet. Its good for our company. Some day, you are gonna be telling a customer how you fought it too, just like I do all the time. You can't stop evolution. Tankless is coming, and coming for good.

 

[Master Plumber Mark]

Sometimes It Scares Me

RUGGED STATED

[. (Pratically the only simple knowledge that people understand in relation to their water heater. Some don't even know if it is gas or electric.)


If they say "white pipe" then I know to shoot the call to another company for repair.


It really scares me sometimes when I talk to people
that dont even know wether they have a gas or electric water heater....


I usually ask them if it has a smoke stack on it that looks like
the "tin man " in the movie Wizard of Oz....LOL


Most can pay their bills,
and they Remember to budget for their cigaretts and booze
and lottery tickets...

and most have the technical knowledge to work the remote on the TV
and they can get their VCR to tape every episode of their favorite soap
shows on TV while they are gone on vacation,

they can throw a meal in a microwave oven........

but ask them if they have a gas or electric hot water heater and
they are totally lost.....


I ask....do you pay a gas bill???....



It makes me wonder and scares me too......
If their were ever a natrual disaster like an earth quake
how would they function till the power came back???

you would have to circle the wagons if you had
supplies and wait till the calvary arrived I suppose....

 

[Barrybpdx]

just scanned through the Brad White product pages. a big difference that wasn't really discussed here is that DV pulls in combustion air from outside. granted this requires a bigger or second hole.
Brad White also says they sell an extension kit to allow their DV to vent 8' horizontally and/or vertically. this seems to make DV a very attractive alternative to power vent (less moving parts) when you don't have a chimney handy.
'regular' power vent does not bring in combustion air. when people here have been saying 'power vent', do they actually mean 'power direct vent'? the combustion air issue seems like it should be important to people(?)
then again if you have a radon problem, just smash some holes in your slab, run a power vent, and you've killed two birds with one stone