New Water Heater

[dlpz]

Water tank is on the way out, apparently my wife told me this a week ago, I can't recall. Filled the tub for a bath for the boy and before getting half way full it was cold. I can't say how old it is but definitely 15+. Before I run down to HD/or Blowes and buy a plug in replacement (nat. gas) should I consider any thing else like an on demand water heater? I'm all in for efficiency but not for blowing a beer budget on champagne taste.

 

[velvetfoot]

Not that it's not bad, but how do nat. gas water heaters fail?
Does a lot of mineral get deposited on the heat transfer surfaces?
I've drained out the bottom of my natural gas heater in the past - garden hose connection, run til clear as I recall.

 

[dlpz]

Wish I knew.

Is it at end of life and should I buy a new one, do they make a more efficient water heater at a reasonable pricepoint? I don't mind replacing it vs trying to extend its life. I'm going to have to buy a new one sooner or later. To me it's worth replacing if its an upgrade, and it contributes to using less nat. gas. Call me lazy but I think at the age of it, it should go to the curb.

 

[Czech]

I replaced my NG tank heater last year, the other one was 15+ years also. It failed by leaking, the tank was shot. I looked at the tankless models, but the pay back was 10+ years or more due to the required venting. With the new one, I replaced the plastic drain valve with a full flow 3/4 brass ball valve immediately, I drain it twice a year or so. Not a good idea from what I've heard unless you do it from new, if an old tank is silted up it may cause more problems than anything. I did not spring for the high efficiency models even tanked, again the price didn't seem worth it at the time. I did wrap the new one with a tank blanket, even though it did not call for it, just need to make sure not to impeded the air vents and hot exhaust. As mentioned above, I agree and think that the tanks just fill with silt eventually which cause the heat not to transfer well into the water, but check to be sure everything else is working correctly such as the burner, thermo couple, ignition, etc.

 

[Highbeam]

The gas tank heaters are so simple that it is hard to imagine how it would foul up EXCEPT for the obvious tank filure where water leaks out. The most cost effective thing to do is to perform some maintenance in place to see if you can get it working again. Maybe start researching replacement options a bit later.

Somebody probably walked by and spun your thermostat setting to warm. This would become apparent when you turn your tub's faucet to full hot to fill it and run the tank out right away. Easy to check.

With all plumbing energized, go ahead and relieve a healthy several gallons of water out of the lower drain. It will be muddy at first and then clear up. This is how I filled up my carwash bucket for years.

 

[d.n.f.]

dip tubes can go if you live in a hard water environment. Have had two go in five years. Once I started draining a few gallons out every month it stopped happening.

 

[Czech]

Just don't release the temp/pressure valve, often times you'll never get it to seat fully again on older heaters.

 

[TMonter]

Something else with any water to watch out for is the cathodic protection. The difference between a 12YR warranty and 6YR warranty water heater is one thing: The anode.

http://www.waterheaterrescue.com/pages/WHRpages/English/Longevity/water-heater-anodes.html

Just don’t release the temp/pressure valve, often times you’ll never get it to seat fully again on older heaters.

Actually you want to operate that valve at least once every couple years to make sure it operates. The trick is to flush the tank before testing the valve. If the valve fails your water heater can be very dangerous.

 

[Czech]

One other thing that I thought about, semi-related. Everytime we leave the house more than a day or so, when we return and run hot water, it takes a bit to wake the tank up. Last night after being gone a couple days, the first attempt at bathing the boys was no good, luke warm water. It got hot after a half hour or so, but I think that the newer tanks may 'go to sleep' if not in use after a certain time. This wouldn't apply to your 15+ year old tank, just though it may be of interest to others that get cool water with newer tanks.

 

[Eric Johnson]

Could be a problem with the ignitor or something else wrong with the burner. If it's not leaking, I'd try to fix it. Gas HW heaters cost more than electric, and the code in your area might require that it be connected by a qualified technician. The authorities are funny when it comes to NG. Not that you can't do it yourself (I would), but if you have a problem, the insurance co. might decide to deny the claim. Or so I've heard.

 

[Metal]

I would replace it, being 15 years in it is well past it's lifespan and the new ones are much more efficient (better insulated, igniters instead of pilot lights, etc.). You could dump a hundred bucks in it and then come home to a wet floor in a few months. A new one will cost you ~$300 (if you do the install, which in most locales is okay, check to be sure).

I would forgo the tankless unless you have a huge spa tub you need to fill or multihead showers that suck your tank dry (it is cheaper to get a bigger tank then to go tankless).

 

[nshif]

Just installed a Bosch 2400 Auqa Star ondemand. Suppose to handle 2 major demands no problem. A bit pricey but it did qualify for a 300$ fed tax credit. ( which I beleive ended at the end of 07) New const install so I had to buy vent pipe anyway, but this pipe was more expensive so either way was not going to be cheap cause I have to vent through the wall not the roof. At the cost of Propane I think Ill make up the diff in cost to operate before to long, Plus no tank to worry about rusting out.

 

[James]

before replacing the tank, take the cold water conection off and pull out the plastic tube. If it isn't almost as long as the tank is tall and looks broken then the cold water that comes into the tank is allowed to mix with the hot and then flow imediately out. When you run your hot water it probably used to go from Hot to Cold quickly when it ran out, but now if its the problem I'm describing it would only be Hot for a short time and then luke warm for a long while.
Most tanks fail by leaking, if your tank is on cement and a leak from your tank won't be too much of a mess I'd wait till it leaks before replacing it (save your beer money), the older tanks seem to last longer than the new ones... maybe it'll last until the tankless ones come down in price....

 

[Metal]

I don't foresee the tankless units coming down in price, they are built on technology that has been around for some time (overseas and here at home) and the majority of the venting cost comes from the fact that most of them are condensing appliances and require special Stainless Steel venting (expensive). A new tank unit will save you money due to the better insulation alone. Repairing a 15 year old water heater is like trying to fix a 15 year old TV, probably not worth your time.

 

[dlpz]

Thanks for the advice!

Lot's of options, I'll have to tinker this weekend and see it's something like you guys suggested. Took a shower this morning and had to crank it all the way hot to get a warm shower. My wife took her shower later in the day and said it was fine.

 

[pdboilermaker]

I replaced mine with a tankless and love it. My brand is a Noritz, check out irawoodsandson.com for several brands. When I began looking to rplace my old 40 gal lp unit I was going to have to replace it with a 50 gal plus so everyone could get a shower w/o being cold. For some reason, 3 years back a 40 gal was around $240 but a 50 gal was around $500.

I thought that there had to be something else so I searched the net and found Ira Woods and Sons. I saw that the biggest Noritz that there was (6 gpm) was $1100.00 then I started looking into it. There was a $300.00 dollar tax credit for going tankless (still in effect), and according to the Department of Energy website, if LP was $1.20/gal (Doouble that now) and you used 60gal of hot water a day (there is 6 of us showering daily, not to mention cloths, dishes etc..) you would save $34.00/month.

So I looked at it like this
Tankless = 1100
50 gal = 500
Difference = 600

600 difference /34 savings per month = 17 months to make the difference, then everything after that is my money. This doesnt include the $300 tax credit.

You dont need as much exhaust pipe if you mount on an exterior wall, on my unit, I come out of the unit that has a built in backflow preventer with a 90 degree ellbow, have 6" of pipe to go through my wall, and a termination cap.

Over the life of the unit, you will save so much money that it is easily worth it plus you never run out of hot water. At the same time I can run 3 showers, the dishwasher, and 2 sinks before the unit cant keep up. (I just had to see how much I COULD do when I first installed it)

 

[TMonter]

Over the life of the unit, you will save so much money that it is easily worth it plus you never run out of hot water.

I did an analysis I posted a while back of a tankless versus a tank model and 90% of people will take at least 4-5 years with the price of a tankless.

Tankless have average efficiency of 85-90%

Tank units are about 65%

If you spend $40.00/month on natural gas that's equal to 4 million Btu at $10.00/million.

If you are using a tankless that means you captured 90% or 3.6 MMBtu

If you have a tank model you need 5.54 Million Btu of gas to get the same hot water

That means you save $15.38 per month

Over 1 year that is: $184.61 which means it's going to take 4-5 years to pay off the tankless.

If you give me your current water heater efficiency and your average yearly usage I can tell you what your savings will be.

 

[pdboilermaker]

Tmonter:

Over 1 year that is: $184.61 which means it’s going to take 4-5 years to pay off the tankless.

Dont forget that you only need to determine the DIFFERENCE in the price of the tank type/tankless type because you have to by the water heater anyway. Savings of 184.61/year for 4-5 years = $738.44-923.05. This is way more than the DIFFERENCE between the two types.

The water heater has to go in in new construction the water heater that is ruined has to be replaced.

 

[TMonter]

This is way more than the DIFFERENCE between the two types.

For a tankless you have to include wiring and additional gas piping and likely will have to be done by a professional which adds another 4-500 dollars (for replacing an existing). This cost would not exist with another tank-type heater. If he's not going to stay in the house for at least 5 years, buying a tankless is a waste of money. A natural vent tank type heater (50 Gallon) from home Depot/Lowes is about $300.00 and about $450 for a power vent.

I don't disagree that a tankless can save money under the right conditions but lets make sure we have the facts so he can make the best decision possible.

 

[pdboilermaker]

Sorry, mine was a direct replacement, bought the gas line at Lowe's, I think it was like $4.46. Didnt realize that you must tear your house down by a pro contractor and have it rebuilt to add a couple feet of copper.

 

[velvetfoot]

Let me chime in here and say the power vented gas water heater I had was noisy.

 

[TMonter]

Sorry, mine was a direct replacement, bought the gas line at Lowe’s, I think it was like $4.46. Didnt realize that you must tear your house down by a pro contractor and have it rebuilt to add a couple feet of copper.

But you did it yourself, the question is can he do it himself. Also copper cannot be used for natural gas, that violates code.

The other question is does the line have enough flow for a tankless? What size is the line? Is power available?

We don't know the details and until we do, telling him one type of heater is better than another is not only being unrealistic we could be downright wrong.

We also don't know his budget.

Let me chime in here and say the power vented gas water heater I had was noisy.

Mine is somewhat noisy but because of the location and having to vent out of the side of the house it was the only realistic option.

 

[Czech]

If copper violates code, our city is in big trouble. Just has to be the correct 'type' of copper. What violates code is the single wall flex connectors sold at the big box stores, give me copper any day. Monter, does the price of the NG tankless include the hundreds of dollars in venting? That's when I stopped even considering a tankless.

 

[Metal]

Another problem with tankless is most need electricity to run, so if the power goes out you are SOL.

 

[TMonter]

If copper violates code, our city is in big trouble. Just has to be the correct ‘type’ of copper.

Per our local codes all new gas piping must be black iron un-galvanized. I believe copper corrodes over time in the presence of natural gas and will eventually leak. Another reason the local inspector told me was that it's hard to differentiate copper water pipes from gas pipes and they like to keep them separate.

Monter, does the price of the NG tankless include the hundreds of dollars in venting? That’s when I stopped even considering a tankless.

No, but some tankless units can mount on an outside wall for easy quick venting.

When I replaced my water heater I looked at tankless but the overall cost was an additional $1200-1300 and I was only going to save $9-11 per month. I didn't have an extra $1100+ to spend so I bought another powervent model.

Mine was a GE (Rheem).