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The good ‘ol water heater debate

HarnessedPowerHarnessedPower Member Posts: 8
So...

The time has come to replace my hot water maker - my current unit is a 50 gallon Richmond, natural gas, power-vent unit. It is now 17 years old, and has been making some interesting “crackling” noises from deep inside over the last year. I’m guessing that the glass lining is coming apart. We have had absolutely ZERO problems with this unit - and I mean not a single solitary one. It has been the single best water heater that I have ever had the pleasure of living with.

Between the sounds, the age, and the fact that it doesn’t seem to make as much hot water as it used to (plus it just isn’t as hot, at least according to my wife and two teen daughters), I think it may have lost its dip tube and it’s time to replace it.

I’ve been debating three options: a like-for-like replacement using a Rheem 50 gallon natgas power vent unit, a to-be-determined tankless unit, or an indirect tank to be paired with our Burnham hot water boiler, which is 5 years old, natural gas, and about 90k btu input (we have large cast iron radiators).

All in all, the 50 gal tank is the cheapest option, and seems to be the most logical and requires the least modifications to the plumbing. The current unit vents out the foundation wall 3 feet away, so venting is super simple. The boiler and water heater are the only gas appliances in the house, both within 15 feet of the outside meter.

For some extra info: we live in northern Wisconsin. Our incoming water temp in the winter can be as low as 36°f (I’ve checked). We have one full bath with a “regular size” cast iron tub/shower. A laundry sink/washer in the basement, but all laundry is washed cold. Kitchen sink and dishwasher. And that’s about it, honestly. Not huge demand, but.... a wife and two teens that all love long, hot showers. Also, our water is drawn directly from Lake Superior, and is fantastically clean and barely treated - thus the 17 year life of the current unit, I imagine.

So......Thoughts? Opinions? Experiences?

Thank you all in advance, I’ll check back in a few hours after I fix yet another emissions-related failure on my 3 year old minivan. Sigh.

Comments

  • flat_twinflat_twin Member Posts: 256
    How often did you flush the water heater? Was the anode rod ever replaced? If the answer is never, 17 years is a pretty good run. The crackling sound and not as much hot water capacity could also be a sign of mineral build up so I'm curious about your actual water hardness. A missing dip tube would be much more of a noticeable problem especially with very cold incoming water. I think you're right about 36 degree incoming water being a lot for a tankless unit to overcome.
    It might be useful to have your water tested for hardness and chlorides.
    What model and btu rating is your Burnham boiler?
  • HarnessedPowerHarnessedPower Member Posts: 8
    We bought our house in 2011, and the tank had the original receipt taped to the side (still there, actually), showing it was purchased & installed in September 2003. It was winterized once due to the house being in foreclosure.

    We have never flushed or emptied it, never attempted to change the anode. At this point, it is what it is. Obviously I’ll care for whatever we replace it with quite a bit differently than this one.

    I had budgeted for its replacement right away, figuring it was at the end of its useful life, but it just kept going and we found more important uses for the money (namely, a boiler shortly thereafter).

    The boiler is a Burnham ESC4. 91,000btu input, 78,000 net output, 68,000 DOE I believe. This boiler, like the water heater, is also vented directly out of the adjacent foundation wall.

    I’ll recheck the last water test results, but we have zero issues here with stains, buildup, mineral deposits, taste, odor, etc. The water plant pulls “surface water” as they classify it, out of Lake Superior about a half a mile offshore at a depth of about 120 feet.

    That said, I’d certainly try flushing out the old tank, but I’d just assume have it’s replacement here and ready to go, just in case. My wife doesn’t ask me for much, but hot showers after work are a must, so downtime will need to be minimal. Heh.
  • Jamie HallJamie Hall Member Posts: 12,863
    Go like for like. At least in my opinion. I have always preferred stand alone, although a very high quality indirect job can work almost as well. An oversized for the flow tankless might work, but with your cold incoming water it will be pushing it -- and if it doesn't, whether you are happy or not, the ladies won't be, and that's not good. After all... the setup you have worked for 17 years -- why change?
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
    HarnessedPower
  • HarnessedPowerHarnessedPower Member Posts: 8
    I think that’s the way I’m Starting to lean, Mr. Hall. There are some features on the new ones that concern me a little, but that’s life. I believe the burner on my tank is rated at 50,000 btu input, and all the new ones (at least locally) seem to be universally rated at 42,000 - but I’ll wait until I see the tanks in person to believe that. Local home store websites are notorious for incorrect specs.
  • SteamheadSteamhead Member Posts: 13,822
    Meanwhile, @HarnessedPower , flush out your existing tank. Since any sediment coming in will come to rest on the bottom of the tank- right above where the burner is- it will interfere with heating the water.

    The ESC-4 has a 91,000 BTUH input rating, so it will have plenty of capacity to run an indirect. "First Hour Ratings" of various water heaters will vary based on what you're comparing, but Burnham's 30-gallon Alliance LT indirect has a rating of 225 GPH (with a larger boiler than yours) whereas a Bradford White RG2PV50T6N unit is rated 75 GPH from 40,000 BTUH input.

    Like-for-like is the easiest way to go. But the indirect will have more heat-transfer surface than a standard tank-type unit, and should last a lot longer- though your present unit has done extremely well.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
    mattmia2
  • hot_rodhot_rod Member Posts: 13,318
    Cost wise a tank switch wins. It would take some piping modification to add an indirect probably, if you are hiring out the work take that into account.
    How long you plan on living there?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • flat_twinflat_twin Member Posts: 256
    I like the suggestions above. 17 years with no troubles is hard to argue with. We chose a glass lined indirect three years ago and have been very happy with it.
  • mattmia2mattmia2 Member Posts: 1,318
    edited June 7
    Steamhead said:



    The ESC-4 has a 91,000 BTUH input rating, so it will have plenty of capacity to run an indirect. "First Hour Ratings" of various water heaters will vary based on what you're comparing, but Burnham's 30-gallon Alliance LT indirect has a rating of 225 GPH (with a larger boiler than yours) whereas a Bradford White RG2PV50T6N unit is rated 75 GPH from 40,000 BTUH input.

    EDIT:
    With the smallish size of your boiler and your very cold incoming water, if you go the indirect route you will have to look at this very carefully. You may need a larger tank than you would think to handle a long, hot shower in winter or multiple showers in a row.

    I think the 50,000 btu/hr 50 gallon is somewhat unusual, they are usually 40,000 btu/hr so you are getting more hot water out of that than a typical 50 gallon conventional tank.
  • SteamheadSteamhead Member Posts: 13,822
    mattmia2 said:

    Steamhead said:



    The ESC-4 has a 91,000 BTUH input rating, so it will have plenty of capacity to run an indirect. "First Hour Ratings" of various water heaters will vary based on what you're comparing, but Burnham's 30-gallon Alliance LT indirect has a rating of 225 GPH (with a larger boiler than yours) whereas a Bradford White RG2PV50T6N unit is rated 75 GPH from 40,000 BTUH input.

    With the smallish size of your boiler and your very cold incoming water, if you go the indirect route you will have to look at this very carefully. You may need a larger boiler than you would think to handle a long, hot shower in winter or multiple showers in a row.

    I think the 50,000 btu/hr 50 gallon is somewhat unusual, they are usually 40,000 btu/hr so you are getting more hot water out of that than a typical 50 gallon conventional tank.
    The other way around this would be to use a larger indirect. But with the same size boiler, it would take longer to recover.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
    mattmia2
  • mattmia2mattmia2 Member Posts: 1,318
    Steamhead said:

    mattmia2 said:

    Steamhead said:



    The ESC-4 has a 91,000 BTUH input rating, so it will have plenty of capacity to run an indirect. "First Hour Ratings" of various water heaters will vary based on what you're comparing, but Burnham's 30-gallon Alliance LT indirect has a rating of 225 GPH (with a larger boiler than yours) whereas a Bradford White RG2PV50T6N unit is rated 75 GPH from 40,000 BTUH input.

    With the smallish size of your boiler and your very cold incoming water, if you go the indirect route you will have to look at this very carefully. You may need a larger boiler than you would think to handle a long, hot shower in winter or multiple showers in a row.

    I think the 50,000 btu/hr 50 gallon is somewhat unusual, they are usually 40,000 btu/hr so you are getting more hot water out of that than a typical 50 gallon conventional tank.
    The other way around this would be to use a larger indirect. But with the same size boiler, it would take longer to recover.
    That's what I meant, bigger indirect. Sorry for the confusion.
  • HarnessedPowerHarnessedPower Member Posts: 8
    The indirect is a plan that I’ve been kicking around for quite awhile - ever since we installed the boiler, really. The sizing and all the different varieties give me pause, though... I’ve been reading here on the Wall and all of Dan’s books since we realized a new boiler was on the horizon, but obviously it’s not something I want to get wrong on the first shot.

    I’ll try flushing out the current heater and see what happens - worst case, I need to go pick up a replacement today.

    The ESC can apparently control an indirect circulator using a built-in second set of thermostat terminals, so I should be good in that regard, without any other controls or relay boxes.

    I guess I’ll keep thinking about it - unless the flush doesn’t go so well (ha ha).
  • HarnessedPowerHarnessedPower Member Posts: 8
    Oops, missed Hot Rod’s question: we intend to be here for quite some time, but if forced to estimate the low end, I would suppose another decade at the minimum.
  • mattmia2mattmia2 Member Posts: 1,318
    the most likely problem you will have with flushing is thew drain won't open or won't close or will be clogged with sediment.
  • HVACNUTHVACNUT Member Posts: 3,369
    > @HarnessedPower said:
    >
    > The ESC can apparently control an indirect circulator using a built-in second set of thermostat terminals, so I should be good in that regard, without any other controls or relay boxes.
    >
    >


    Yeah it looks like P1 (Red wire) and P8 are the line and low volt connections for an indirect.

    I'm not too familiar with the ESC but I see it uses full 1 1/4" supply and return manifolds, and the indirect's return comes in below the boiler bypass, if needed. Stay within their specs.
  • hot_rodhot_rod Member Posts: 13,318
    > @HarnessedPower said:
    > Oops, missed Hot Rod’s question: we intend to be here for quite some time, but if forced to estimate the low end, I would suppose another decade at the minimum.

    If you plan on staying it may be worth the $$ upgrade to an indirect. Some brands carry lifetime warranty.

    You original post mentioned cost being a concern so my first thought was a tank replacement. I doubt an indirect powered by a cast boiler will be much if any less to operate, you need to fire and heat the boiler mass in non heat season, and any heat transfer will cost some efficiency loss.

    Try and flush, typically 17 years of mineral deposit would need a wand or muck vac to remove enough sediment to get the tank back to new operating condition.
    Very small amount of heavy calcium sediment will flush from the drain cock with just city pressure.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Larry WeingartenLarry Weingarten Member Posts: 1,803
    Hi, A few thoughts. Seventeen years is a good run as tank-type heaters average 9-12 years. Still, I think it could be useful to have a look at what's left of the existing anode. It's the best clue about the condition of the tank. I'd be surprised if there is any sacrificial metal left on it, but your good water might have slowed the anode down. IF there is even a little sacrificial metal, you could keep the heater going. If you attempt that, I'd replace the dip tube with a curved one, and drain valve with a full port ball valve so you can better flush sediment from the tank. Lastly, have a look at any showerheads and measure flow. You want 2.5 gpm or less. Simply replacing that could let you get a smaller tank. :)

    Yours, Larry
  • Paul PolletsPaul Pollets Member Posts: 3,293
    If you're looking for lifetime performance, try the Viessmann VitoCell 300 indirect tanks. They're made of 316Ti stainless and have the largest (and longest) coils. The resistance to corrosion exceeds other tanks and there's a lifetime warranty to original owner. The specs call out incoming cold water requirements. A 53g tank would easily provide adequate DHW for the residence. If cost is an issue, the replacement gas water heater will always be less.
  • george_42george_42 Member Posts: 85
    just put in a replacement water heater. Cheaper and less trouble and will not have to run hot boiler in warm months
  • Paul PolletsPaul Pollets Member Posts: 3,293
    Boilers using indirect tanks are wired so that the boiler only comes on when the indirect needs recovery, using priority zoning. Water heaters are always less expensive than indirects. So is a Kia. An indirect tank has no moving parts, other than the circulator that recovers the tank coil. Hydronic boilers are well suited to provide DHW with indirects. If the boiler has an integral computer control, the operating costs will usually be less to recover the tank, compared to a separate gas fired tank.
  • flat_twinflat_twin Member Posts: 256
    Not to sideline the discussion but... Any opinion on the benefits of an indirect WH regarding running a boiler (in my case a modcon) daily rather than let the boiler sit idle for five months May-October? I know my vehicles are better off being used on a regular basis instead of sitting around.
  • ChrisJChrisJ Member Posts: 11,004
    Back in 2011 when we bought our house we had a tankless coil in the boiler. Late 2011 I made the decision to ditch it all and do a 50gal power vented Bradford White tank heater. I'd do the same today.

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Paul PolletsPaul Pollets Member Posts: 3,293
    The indirect tank doesn't sit "idle" with a modcon. When there is a draw on the tank, the boiler will usually fire and recharge the tank when there is a 7 degree differential. The boiler also modulates to high fire for the duration of the tank recovery. Some mod cons will even exercise the pumps if they're not used within 72 hrs. Standby loss is also much lower if the tank has adequate insulation and compared to the losses of a flueway in a gas fired heater.
    delta T
  • jumperjumper Member Posts: 1,453
    george_42 said:

    just put in a replacement water heater. Cheaper and less trouble and will not have to run hot boiler in warm months

    I agree. Also efficiency arguments can be misleading. For example look at inefficiency times burner size. While firing a 90% efficient 100,000 btu burner wastes just as much as an 80% 50,000 burner. If your water heater runs a lot then the 90% works less than half as long and saves a lot of gas. But that situation is not so common.

  • mattmia2mattmia2 Member Posts: 1,318
    edited June 12
    If you've sized the tank right, it should also be firing for about half the total comparative time. The thermal efficiency of a standard water heater is probably 50%-60% plus huge standby losses from the inability to insulate the bottom or center of the tank.
    Canucker
  • hot_rodhot_rod Member Posts: 13,318
    That would be an interesting comparison from a fuel consumption standpoint.
    A power vented water heater vs a cast boiler and indirect.

    Power vented do have a bit less flue loss compared to standard tanks. And you need to look at loss from that cast boiler in the summer every time it fires and cools for a DHW call. New DHW tanks are probably better insulated than that boiler. I'd guess they would be fairly close in fuel- water efficiency.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • ChrisJChrisJ Member Posts: 11,004
    hot_rod said:

    That would be an interesting comparison from a fuel consumption standpoint.
    A power vented water heater vs a cast boiler and indirect.

    Power vented do have a bit less flue loss compared to standard tanks. And you need to look at loss from that cast boiler in the summer every time it fires and cools for a DHW call. New DHW tanks are probably better insulated than that boiler. I'd guess they would be fairly close in fuel- water efficiency.

    Back in 2011 when I bought mine you were able to get 2" insulation on a power vent heater, but I think mine is the normal 1".
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • STEAM DOCTORSTEAM DOCTOR Member Posts: 1,164
    > @mattmia2 said:
    > If you've sized the tank right, it should also be firing for about half the total competitive time. The thermal efficiency of a standard water heater is probably 50%-60% plus huge standby losses from the inability to insulate the bottom or center of the tank.

    Standby losses is an interesting discussion. I have been in boiler rooms for 12+ hours strait. The tank water heaters will fire once at most( when not being used). Obviously not a scientific study but food for thought. I remember being quite surprised when it hit me that water heaters really don't fire much if they are not being used.
    ChrisJmattmia2
  • ChrisJChrisJ Member Posts: 11,004

    > @mattmia2 said:

    > If you've sized the tank right, it should also be firing for about half the total competitive time. The thermal efficiency of a standard water heater is probably 50%-60% plus huge standby losses from the inability to insulate the bottom or center of the tank.



    Standby losses is an interesting discussion. I have been in boiler rooms for 12+ hours strait. The tank water heaters will fire once at most( when not being used). Obviously not a scientific study but food for thought. I remember being quite surprised when it hit me that water heaters really don't fire much if they are not being used.

    My PV Bradford White 50 Gal was still very very hot after not having electric for 3 days after Sandy. I was amazed, actually.

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • jumperjumper Member Posts: 1,453
    >>Standby losses is an interesting discussion. I have been in boiler rooms for 12+ hours strait. The tank water heaters will fire once at most( when not being used). Obviously not a scientific study but food for thought. I remember being quite surprised when it hit me that water heaters really don't fire much if they are not being used.<<

    My subjective impression is opposite. As soon as one person in a multi-unit building takes shower or does laundry the heater goes on! So if one cares that much about fuel consumption the heater should have a broad range & then temper output with mixing valve. You can also save some energy with extra insulation. There are other schemes to squeeze energy consumption for DHW. In younger and more enthusiastic days I tried some. Concluded that the pay-off is not worth it. Complications cost $$ and eventually get knuckleheaded. So I recommend simple atmospheric burner storage tank. The one thing I may try for something like a motel is tank heaters in series and maybe a tempering valve. For safety you want two tempering valves. See what I mean about complications?
    mattmia2
  • flat_twinflat_twin Member Posts: 256
    HTP Superstor for example lists standby temp loss at less than 1/2 degree per hour. So with no water draw and a 7 degree aquastat swing the boiler will fire slightly less than twice a day.
  • mattmia2mattmia2 Member Posts: 1,318
    I have thought about using 2 very small modcon boilers, preferably with 10:1 turndown or more for a residential system instead of one large one(maybe one smaller and one larger), the smallest one can run low fire to nearly match a single room calling on a mild day, they can both run high fire to pick up a big indirect water heating load. Of course it would cost more than it ever would save in energy although it might get comparable in cost to a buffer tank for the ability to accommodate microzoning.
  • ethicalpaulethicalpaul Member Posts: 1,610
    edited June 12
    I have been loving my heat pump water heater. Check out the kWh usage per day. It's almost free. Plus it dehumidifies my basement in the summer, a little :) (in the winter it's already dry down there and there's no condensation)


    1 pipe Utica 112 in Cedar Grove, NJ, coal > oil > NG
  • Paul PolletsPaul Pollets Member Posts: 3,293
    Some projects use 2 mod cons, even when loads are small. I've seen a 2 boiler design used in a 4000SF home. Sometimes one of the mod cons is dedicated to DHW production only. Since mod cons have a sweet spot, I prefer to design for the load. If there is a large demand for DHW, I'll size the indirect and boiler accordingly.
    I prefer one mod con, unless a cascade system is needed.
    BTW, here's Viessmann's new commercial water heater station:
    https://www.viessmann-us.com/en/commercial/dhw/on-demand-dhw/vitotrans_300.html
    mattmia2
  • hot_rodhot_rod Member Posts: 13,318
    flat_twin said:

    HTP Superstor for example lists standby temp loss at less than 1/2 degree per hour. So with no water draw and a 7 degree aquastat swing the boiler will fire slightly less than twice a day.

    I think those standby losses on indirects are a bit embellished?
    I have heard some are tested in an 80° ambient room with low tank temperatures. I don't know that there is a standard that they are tested to?

    One tank manufacturer brought a bunch of brands into their lab and tested all at the same condition, results varied.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • hot_rodhot_rod Member Posts: 13,318
    mattmia2 said:

    I have thought about using 2 very small modcon boilers, preferably with 10:1 turndown or more for a residential system instead of one large one(maybe one smaller and one larger), the smallest one can run low fire to nearly match a single room calling on a mild day, they can both run high fire to pick up a big indirect water heating load. Of course it would cost more than it ever would save in energy although it might get comparable in cost to a buffer tank for the ability to accommodate microzoning.

    I think to optimize a mod con firing an indirect you would want an indirect with a large coil or surface area. Generate 120F DHW with 125F supply, maximize condensing operation. A dual coil tank with coils in series for example, I've done that with solar tanks to maximize heat exchange.

    It a tough prediction what a family needs or wants for DHW. Some families do fine with 40 gallon, other burn through 120 and want more.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
    Paul Polletsmattmia2
  • mattmia2mattmia2 Member Posts: 1,318
    edited June 12
    hot_rod said:

    flat_twin said:

    HTP Superstor for example lists standby temp loss at less than 1/2 degree per hour. So with no water draw and a 7 degree aquastat swing the boiler will fire slightly less than twice a day.

    I think those standby losses on indirects are a bit embellished?
    I have heard some are tested in an 80° ambient room with low tank temperatures. I don't know that there is a standard that they are tested to?

    One tank manufacturer brought a bunch of brands into their lab and tested all at the same condition, results varied.
    HTP gives the same loss for like a 20 gallon and a 120 gallon tank in degrees per hour. A 20 gallon and a 120 gallon have a very different ratio of surface area to volume of water so they can't have the same loss if expressed as degrees per hour.
  • jumperjumper Member Posts: 1,453
    >>I have been loving my heat pump water heater. Check out the kWh usage per day. It's almost free. Plus it dehumidifies my basement in the summer, a little :) (in the winter it's already dry down there and there's no condensation)<<

    Reminds me of when I used a lady's A/C to heat her swimming pool. Totally free heat. Summer was only half over when pool got much too warm.
    CLamb
  • ChrisJChrisJ Member Posts: 11,004
    > @jumper said:
    > >>I have been loving my heat pump water heater. Check out the kWh usage per day. It's almost free. Plus it dehumidifies my basement in the summer, a little :) (in the winter it's already dry down there and there's no condensation)<<
    >
    > Reminds me of when I used a lady's A/C to heat her swimming pool. Totally free heat. Summer was only half over when pool got much too warm.

    How did you build that?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • jumperjumper Member Posts: 1,453
    @ChrisJ
    Just recirculated pool water through A/C condenser. No big deal in those days before Montreal Protocol & double walled heat exchanger laws. Probably drove up power consumption on A/C as water warmed up. Still less than air-cooled A/C. Who says there's no free lunch?
    Sometimes I try to calculate if a fountain can cool pool water sufficiently overnight.
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