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Tough Heating Choice in MA

JesseWJesseW Posts: 3Member
edited October 11 in Domestic Hot Water
Hello Heating Folk -

Just bought a house with an older (25 yr) Buderus boiler which clocks in still at 86.5% efficient. It has an internal-to-boiler tankless coil water heater which just doesn't provide enough heat to fill the Jacuzzi tub. I don't know how the previous owners lived with this kind of hot water! (BTW had the boiler checked last week and it's in good working condition - service guy even upped the high temp to see if he could get us more hot water at a go, but it was not enough).

I have read quite a bit, and I am still faced with a tough choice and I hoped some folks here could weigh in. I'm probably making some flawed assumptions but I can't seem to get a straight answer from my plumber who is somewhat old-school and only sees storage water tanks as "real" water heaters. He's offering to (begrudgingly) put in a 80 gal B&W hybrid for $ OR a new storage tank of the same capacity for $ less.

I like the emerging Hybrid water heaters, but I don't see many fantastic reviews online of these units except from pro-tech fanboys that are just wanting to write for the internet. They seem to break a lot and the electronics, although cool, seem like they could be a maintenance pain point, esp since most of the major manufacturers of these seem to have really poor customer service and they get wildly tricky and unhelpful with warantees. Most plumbers seem to dislike them. I like them because they are quite efficient, and reduce the dependence on the fossil fuels, esp because this boiler only has 5-10yr left on it -- I don't want to be forced into replacing the boiler with another oil burner because I bought $ worth of indirect water heater! The Rheem model integrates with my Nest and is SmartHome capable which is kinda cool in a useless kind of way.

Then there's the little known twist that the box stores are selling these hybrid models that are subtly inferior to the professional grade - but to get the professional grade I have to go through a contractor that installs professional models for a particular company, so it's almost like I have to figure out what model I want and THEN find a contractor. I read that the box stores' inventory doesn't go through much QA like the pro models, plus they have plastic fittings where the pro use brass, and getting those box store heaters serviced when they have an issue sounds like a real nightmare.

Indirect water heat is of course the other obvious choice. I already have the boiler and it's reasonably efficient. However most of the articles often note "ultra-efficient" oil furnaces as being ideal with this type of hot water system. They don't mention if they are acceptable with less-than-ultra efficient. But I like them because they are simple, last a long time and are touted as being really efficient for those that have a boiler. My oil co can put in a new HTC for about $. I know I need to get some more quotes.

Other hot-water related facts involved here:
  1. Natural gas is not available in my area (Mendon, MA)
  2. My family is small (just 3) but the house has four bedrooms, 2.5 baths, and when we sell could easily go to a larger family of 4 or 5.
  3. The only largeish hot water demand is the Master b/r jacuzzi tub.
  4. Indirect heat is often touted as ideal for larger families. We all work from home so there's no "morning rush" with showers, etc.
  5. Master bath is just about as far from the boiler area as you can get - basement to second floor MBR and 30-40 ft horizontal distance.
  6. I already spent $ on the electric to get 240v over near the boiler, though much of that was putting in a long-overdue subpanel for $. Only $ was for the power run to the boiler. I hadn't heard about indirect heating in time!
  7. MASSSAVE offers a rebate on new indirect hot water systems that replace another fossil-fuel fired boiler (like the tankless coil I have).
  8. I run a dehumidifier all summer (which leans me towards the hybrid a bit more)
  9. Boiler is in the basement with plenty of air around it.
SO which direction would you experienced heater folk recommend in this situation -- indirect or hybrid? Have a favorite brand you have seen works well? Did I miss any key factors? I am really curious if ANY water heater company has good customer service - all I see is complaints. However it may be that those that are happy just don't have time to write into sites to add a five star review.

Stymied in Massachusetts


  • SteamheadSteamhead Posts: 12,331Member
    @JesseW , we do NOT discuss pricing on this board. Click the word "Here" in the yellow banner above to see this and other FAQs.
    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.
  • Jamie HallJamie Hall Posts: 8,741Member
    I don't care for hybrid water heaters, although one of the properties which I care for has one. Why? Because if you want to keep it in hybrid mode, your demand has to be fairly small and well spaced out. With your Jacuzzi you'll be operating in resistance mode most of the time, and that gets expensive unless you electric rates are really low.

    Indirects are good and relatively inexpensive -- and can pair with any boiler, new or old. Plumbing isn't a big deal on them.

    But... have you considered a direct fire oil burning water heater? They do require an additional flue in most situations, but the recovery is very very fast, which has some real advantages.

    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
  • Erin Holohan HaskellErin Holohan Haskell Posts: 734Member, Moderator, Administrator
    Steamhead said:

    @JesseW , we do NOT discuss pricing on this board. Click the word "Here" in the yellow banner above to see this and other FAQs.

    Thanks, @Steamhead.

    And welcome @JesseW. Please note that we do not discuss pricing here because it could lead to price fixing, which is illegal. Thanks.
  • STEVEusaPASTEVEusaPA Posts: 2,226Member
    edited October 10
    Pretty much nothing you put in unless it's commercial is going to fill a Jacuzzi tub quick and hot.
    I'd say 60 gal indirect, set boiler control to give domestic hot water priority, fill tub slow is probably your only way.
  • ZmanZman Posts: 4,358Member
    Have you tried filling the tub more slowly? Tubs often have very high flow rate valves which tend to overwhelm tankless coils.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • New England SteamWorksNew England SteamWorks Posts: 1,127Member
    You need an indirect. Size it to the jacuzzi and you'll be fine.

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
  • delta Tdelta T Posts: 663Member
    One good way to squeeze more hot water our of an indirect water heater is to store the water in the tank at a higher temperature (typically around 140 ) and using a mixing valve to temper the water with cold and only allow 115 or 120 degree water out the house. This is an easy addition in any indirect water heater replacement and you will likely be able to get away with a smaller tank offsetting the extra cost of adding the mixing valve. Would have to know the actual size of the tub and what the flow out of the tub is to size properly.
  • Larry WeingartenLarry Weingarten Posts: 1,354Member
    Hello, Another approach is to install a tankless heater just for the tub. That way a heat pump water heater should easily be able to meet demand and stay in heat pump mode most of the time. I'd probably install them in series. ;)

    Yours, Larry
  • LeonardLeonard Posts: 470Member
    edited October 11
    As a kid when my furnace was about 15 years old the domestic hot water (DHW)coil in boiler water jacket got "calcified" (mineral deposits on inside walls). This insulated it somewhat and hot water coming out was not as hot as before.

    Heating tech replaced coil and we had hot water again.

    Then in another ~15 years it happened again. Talked to heating tech at large apt complex and found they dissolve the internal calcium deposits in coil with an acid product named Sizzle (sulfuric acid). I only had muric acid (~ 35% hydrochloric acid) , I put that into the coil for ~ 3 hours, while furnace was hot ~ 180 degs. Then rinsed well, some bright copper particles came out , so I guess I left it in there too long. Now had plenty of HOT water.

    More recently I was getting cool water,........ I assumed I need to re-acid the coil. Turns out mixing/tempering valve was bad. Mine only had a manual water valve between hot and cold lines ....... rubber washer seat on valve went bad and allow a leak between the pipes. Takes very little 42 deg cold water to make hot water cooler (I needed HOT ~ 120 deg water for a bug issue in laundry). Feeling hot water line before and after mixing valve will give you a hint if valve is cooling the water.

    Before I figured out mixing valve was bad I added foam insulation to hot water pipe from furnace to bath room, that reduced temp loss while flowing by ~ 10 degs. Previously it was bare 1/2 inch copper pipe in ~ 60 deg cellar, maybe 30-40 foot run.

    My DHW coil has 2 parallel finned tubes, I've noticed sometimes water temp seems to "toggle" between hot and warm. I suspected debris intermittently plugged one of the tubes. I've seen all kinds of junk debris in water pipes , ranging from rubber washer from water meter installation, to parts of broken valves seals at furnace washing downsteam to shower valve and plugging flow of hot water, so I got a cold shower. Also seen a 40 year old steel plug in a water pipe copper Tee so badly rusted that rust extended into the tee choking off water flow.
  • HVACNUTHVACNUT Posts: 1,521Member
    edited October 11

    Can you post some pics because I have never in my 30+ years in the field, seen a Buderus with a tankless coil?
    Did you find the unicorn?

    Seriously post some pics of the boiler and connected piping.
    What model Buderus?
    What oil burner?

    I dont think you could go wrong with a reverse indirect like a Turbo Max "23" and a thermostatic mixing valve.
    The boiler manifolds might have to be re piped to accept the 1 1/4 connections of the Turbo Max but it will give you all the hot water you need.
  • billtheplmbr3845billtheplmbr3845 Posts: 23Member
    Yes, would love to see the Buderus with a tankless. I do not recommend a homeowner trying to clear the tankless with acid. It can be fairly dangerous, and you always have the possibility of burning a hole in the tubing which will lead to more headaches . Put in an indirect, pipe it from the boiler in 1",set the aqustat to 140 or so and install a good quality mixing valve. You'll be glad you did
  • JesseWJesseW Posts: 3Member
    edited October 14
    @HVACNUT you caught me! :* I think I read Burderus somewhere on this forum and confused it with the "B" brand on my boiler plate. I looked again and it's a BURNHAM V-15A T with a Beckett burner (746001). I'll attach a pic anyway to see if you can tell if the manifold will need to be repiped.

    p.s. i am aware of the leak in the tankless coil gasket -- that's gonna have to get replaced as a part of the install of my indirect.

  • JesseWJesseW Posts: 3Member
    edited October 14
    I would like to thank everyone who read my post and responded. Extra kudos to @HVACNUT for the mention of TurboMax I had not heard of reverse indirect heaters. Reviewed it - awesome. The 23 is the smallest unit - would it give enough continuous hot water for a jacuzzi tub? I'm attaching the boiler plate spec.

    There's another old thread on here that goes into using these guys in residential/lower thermal mass situations for those interested.
  • LeonardLeonard Posts: 470Member
    edited October 16
    "Burning a hole in DHW coil" ...... I knew the risks if it made a hole. Acid could blow out, and later my ~12 psi boiler water would get over pressurized by my ~45 psi pottable water.

    Figured I had nothing to lose, coil would other wise have to be replaced as it was.

    I'm a mechanical engineer. I took precautions to handle acid. Full face shield, safty glasses, gloves, thick old winter coat, plastic hat, splash shield in funnel to contain spray if it belched, 5 gal bucket of water, baking soda, garden hose at the ready.

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