Tough Heating Choice in MA

JesseW

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

Steamhead

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

Jamie Hall

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.

Erin Holohan Haskell

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.

STEVEusaPA

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.

Zman

Have you tried filling the tub more slowly? Tubs often have very high flow rate valves which tend to overwhelm tankless coils.

New England SteamWorks

You need an indirect. Size it to the jacuzzi and you'll be fine.

delta T

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 Weingarten

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

Leonard

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.

HVACNUT

@JesseW

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.

billtheplmbr3845

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

JesseW

@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.

JesseW

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.

Leonard

"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.

JesseW

Just thought I'd follow up... we replaced that old boiler with a new Burnham MPO-IQ147 and an HTP SSU-60 indirect water heater and could not be happier. Fills the jacuzzi tub no problem and now showers have consistent, reliable on-demand hot water. Thanks all for your input!

EBEBRATT-Ed

Thanks for the feedback. Glad you got a decent install.

GBart

You may want to consider dumping the whole thing and go with a System 2000, there's about 180 degrees of separation between a Buderus and Burnham, Burnham had a lot of bad blocks, they thinned the cast iron to increase profit, bad move.

You could keep it and go indirect and always change the boiler when it goes.

You need to know the gallons of your tub, as stated, you really should tun the indirect at 140 and install a tempering valve NOT ONLY to increase output but to kill bacteria, 120-125 is a perfect temp for some really nasty bacteria and it causes many respiratory infections.

check this out
https://www.sciencenews.org/blog/science-public/case-very-hot-water

GBart

from the article-- On its website, the Department of Energy notes that, “Although some manufacturers set water heater thermostats at 140 ºF, most households usually only require them set at 120 ºF.” For each 10º drop in temperature, consumers can expect to see a three to five percent savings on energy use. Moreover, DOE points out, setting that thermostat to 120º could extend the heater’s lifetime by slowing the buildup of minerals and corrosion within it.

What DOE and other energy-conservation sites don’t point out is that 140 ºF will kill a number of potentially lethal waterborne organisms, like the ones responsible for Legionnaire’s disease and NTM, short for nontuberculous mycobacterial infections. In contrast, 120º provides a nurturing environment for such toxic microbes

Owing to lead-poisoning concerns, people should never drink hot tap water. That’s why the primary route to respiratory disease from these germs comes through inhalation of the steam associated with showering or hot tubs. Infections due to these home-grown germs are estimated to kill 3,000 to 12,000 Americans annually, Edwards says.

GBart

Personally I like the HTP Ultra Indirects, they put out more hot water for a given size, a 30 gallon can easily do 200GPH.

http://www.htproducts.com/superstor-ultra-waterheater.html

JesseW

Thanks ,@GBart for your contribution. Maybe you didn't catch my last update... the Burnham is in with an HTP SSU60 Indirect. I asked installer to raise the temp (but didn't mention the tempering) and he refused.. seen too many scalding injuries and its outside of code. But I hadn't thought about the tempering valve but even with that, doubt if he'd put it in.

He was even kind enough to push for new circ motors (he pointed out they aren't true pumps) instead of passive valves, which means they can take out one of the heating circuits without taking them all down if there is a problem.

Only issue is that the house seems to warm a good deal slower... have him coming out later in the week to look at that.

DZoro

It's code in most areas to have a mixing valve in the system. Then the temp can properly be set to 140 and mixed down to 120 to prevent scalding.
D

SuperTech

The house warms slower? Why is it cooling off? You should avoid setbacks with hydronic heating. Set it to what you are comfortable with and leave it. A properly sized and installed boiler works best when operated like this.

JesseW

Thanks guys. Yeah, @SuperTech, I got the same message from the heating guy when he came to check it out and do the system baseline measurements after week or two of burn-in. I'm not using a nightly setback anymore. Nest doesn't show it's firing dramatically less total hour-wise but I suppose it's more efficient as you don't keep heating furniture and walls every day!

pecmsg

GBart said:

from the article-- On its website, the Department of Energy notes that, “Although some manufacturers set water heater thermostats at 140 ºF, most households usually only require them set at 120 ºF.” For each 10º drop in temperature, consumers can expect to see a three to five percent savings on energy use. Moreover, DOE points out, setting that thermostat to 120º could extend the heater’s lifetime by slowing the buildup of minerals and corrosion within it.

What DOE and other energy-conservation sites don’t point out is that 140 ºF will kill a number of potentially lethal waterborne organisms, like the ones responsible for Legionnaire’s disease and NTM, short for nontuberculous mycobacterial infections. In contrast, 120º provides a nurturing environment for such toxic microbes

Owing to lead-poisoning concerns, people should never drink hot tap water. That’s why the primary route to respiratory disease from these germs comes through inhalation of the steam associated with showering or hot tubs. Infections due to these home-grown germs are estimated to kill 3,000 to 12,000 Americans annually, Edwards says.

Pay close attention to this. It is correct. Minimum domestic hot water temperatures now are 140°f then tempered down. A few manufactures wont allow there newer controls to be set lower!

Have the installing contractor double check his source of information!

Henry

Legionella survives to 139F. The storage tanks must be at140F. you can put a tempering valve after the tank.

ratio

It's quite believable that something like Legionella will die at right about 139°, but given what I know about consumer-grade temperature control, wouldn't a 5° (or 10. Or more?) safety factor be indicated? What is the dead band of a common water heater thermostat? Is the set point the bottom, middle, or top of the dead band?

JesseW

Question: is Legionella or NTM possible with well water? Or is it a feature of public water supplies?

Ironman

Legionella is in all fresh water. It actually comes from the ground.

pecmsg

Ironman said:

Legionella is in all fresh water. It actually comes from the ground.

https://www.cdc.gov/legionella/about/causes-transmission.html

ethicalpaul

This is coming from a position of ignorance, but:

- I don't want my potable water anywhere near my boiler, let alone running inside it separated by a copper tube!
- I don't want my inefficient boiler running all summer long

But having said that, did your plumber try turning down the flow rate through the coil to give the water some chance to pick up the heat from the boiler?