NJ Boiler replacement decision points...

dgoldstein

My 21 year old HTP Munchie 80M (Nat Gas) is running fine, but if the HX breaks in the middle of winter I'll be up a creek due to no more part availability. The PRV port on the HX is showing corrosion and I'm worried that if I try to open it up to seal it, something may break.

My 7 year old Bradford White power-vent 50 HWH is running fine despite only one flush since new. Yes, I'll do one soon!

I've had three contractors in to give quotes within the last 3 months. All pitched a combi, some boiler only, some boiler+indirect or boilter+htp crossover. Brands: HTP, Velocity, Navien, Lochnivar

We made it a point to tell them that we do not want to run out of DHW if we're going to replace/integrate the HWW with the boiler. They all claim that "we'll have more hot water than we could ever need". We have 2 full baths, 1.75gpm shower heads, washing machine, dishwasher (almost never use), and my partner does take 30+ minute hot showers sometimes after we do a bleach/color job on her hair. We had a 40gal electric HWH and constantly ran out of hot water - so, we still have some PTSD from that, but our 50gal BW unit hasn't really let us down.

I think the key to the Munchie lasting this long is that I've performed service on it, replaced worn parts and have pro comb. analysis done after services. As the homeowner, I don't like not being able to get parts or being mitigated from "right to repair" my own stuff.

The house is a leaky combination of 1950's single-story 2x4 framed beach bungalow over vented sand crawl with ancient R13 in the walls and mostly compressed batts in the attic all attached to a ~2010 2-story addition, also 2x4 walls and 2x6 joists in attic. Lots of leaky vinyl windows. I did as much air sealing as I could in the bungalow attic, but the insulation is toast. I haven't been able to do anything in the 2-story attic due to the joists being covered with plywood and no time to pull and seal. The attic hatches need to be insulated/sealed.

I do realize that it would be helpful to toss the old, mouse pee and poop contaminated 20th-century insulation out and refill the 2x4 bays with R15 and then top with a perpendicular lay of whatever I can squeeze in, R15-19 maybe. It's a very shallow pitch at the eaves and will be nearly impossible to get a ton of insulation over the top of the wall cavity.

The 2010 2-story I could definitely get it up to current code, but would loose a lot of storage space - I know, I know! I shouldn't store stuff in a attic, but we do and until stuff disappears, it is what it is - attempts at air sealing will be the best I can do to improve efficiency any time soon.

I'm in Ocean County, NJ, winter DD is 10-13*F depending on what version of the Manual J you look at. On consecutive cold days with wind, the house will loose 1-2*F of heat from our preferred 69-70*F set-point despite maxing out the temp in the ODR curve. It doesn't happen often and we just get out extra blankets, but it's non-optimal.

None of the contractors offered to do a heat loss calc. Some did ask about how many baths and usage.

We are prone to loosing power due to storms, occasional hurricanes and I do have the house wired to plug in a generator as needed.

I've read some things about combis that make me concerned about an all-in-one unit, reliability and meeting extended DHW demand.

Overall, I'm just not sure how to narrow down the choices or consider something not mentioned.

FYI - I would do my own heat loss, but the Slant/Fin free calc seems to have gone away.

Robertw

Dan,

If you would consider an energy kinetics boiler, we have a great line up of high efficiency side wall vented non condensing as well as condensing boilers. All of our boilers are Made in USA with steel and stainless-steel from local mills. This includes our gas mod con lineup - I wasn't happy(understatement) with the Euro and Asian models that are heavily designed for manufacturing with tiny water passes and tiny flue passes that can foul and fail. Instead of building a boiler around a foreign pressure vessel, we invested heavily in R&D, development, automation, and robotics to design and manufacture our own pressure vessels in Lebanon, NJ. Has all that hard work payed off? The Accel CS condensing boiler has been on the market since 2013 and we have not had a single pressure vessel failure. They cost more, but are well worth it with long life, quiet operation, and extraordinary efficiency built on high performance, serviceable pressure vessels plus thermal purge for both heat and hot water. Our Sealix "non stick" coated plate heat exchangers are designed to make hot water while driving boiler return temperatures down between 80°F to110°F, so condensate rains out in a heavy flow and keeps the fire tubes clean. Our Smart Boost means temperature reset can be set very aggressively and the supply temperature will automatically increase if a specific zone is on long enough to require some higher temperature help, techs don't need an engineering degree to set it for best performance and efficiency.

Of course our spiral pressure vessels used in the System 2000 Frontier/Resolute/Ascent models are also made from specially formulated steel from local mills as well. These are built for ease of service, and although we call them 30 year boilers ,we have boilers still running from 46 years ago when the company was founded. We also go the extra mile with Made in USA components down to parts like Ward fittings cast in Pennsylvania, our Energy Manager (built to Mil Spec standards in the USA), insulation and refractory, powder coated sheet metal jackets, and more. We offer American Made burners, circulators, and safety controls as standard as well (some of these have a few sub components are sourced elsewhere).

We continue to innovate and build on our model of high efficiency, serviceable boilers that are made in USA. Working direct with installing contractors means we have faster feedback and clear intelligence on where we can improve over issues found with non-Energy Kinetics models, and I have to thank our network of high quality contractors, territory managers, and techs that help keep us more than one step ahead.

Feel free to give us a call at 908-735-2066 and we can put you in touch with some of our local dealers.

hot_rod

I'm a proponent of combi units and have owned 6 different brands and models. You will want at least a 120K if you expect 3 gpm.

The output for DHW is directly tied to the incoming water temperature. Any idea what your lowest water temperature drops to?

The math look like this 500 X flow X temperature difference.

So 500 X 3 gpm 110- 55° = 82,000 BTU/hr. a 120 boiler at 85% efficiency= 102,000, BTU/hr.

The next number that you want to know is the heat load, but if the 80K munchkin has been adequate, it is safe to assume 80K or less.

A 120 Combi will turn down to 11,000 BTU/ hr output so it word work well for both DHW and heat.

If you want to run multiple showers or DHW loads, add up the required gpm to size a larger combi. A 150K would get you close to 5 gpm.

I think 3-3.5 gallons per minute is realistic with a 120 combi in your area.

Every few years you may need to de-scale the HX, easily done with a pump and bucket kit. I suggest current mod cons have a 15 year or so life expectancy. Parts availability will be the issue.

We do see 20 year old Munchkins and other brands cross the list occasionally.

Proper installation, adjustments and service are the key in my opinion.

dgoldstein

@Robertw - thanks for the information. I had never heard of your company. I will need to check, but I'm not sure your offerings will fit into the space I have to work with. It's very cramped and is somewhat vertically cut-off depth-wise by a 2nd-floor flight of stairs.

@hot_rod thanks for your insight! I don't know how cold the supply water gets in winter, but it's definitely cold to the touch - maybe 40-50*F. My Munchkin has a DOM of 2004! I believe it was put into service in 2006, but am now not 100% sure other than knowing it's old and parts availability is severely limited.

What does the "110" represent in your equation?

Is that 85% efficiency tied to the advertised boiler efficiency? The ones I'm looking at are all 90%+.

The 80K Munchkin has been 99% adequate except on those single digit cold days and/or combined with wind chill.

We'd probably run our ~2gpm shower for 40 minutes max = 80 gallons of hot water needed. FYI - we keep our HWH at 140*F set-point.

pecmsg

Calling @EzzyT

EBEBRATT-Ed

PM @JohnNY , @EzzyT or @clammy

Alan (California Radiant) Forbes

Jupiter Heating carries most Munchkin parts. I’ve found that Munchkins heating radiators last longer; less acidic condensation in the HX. IBC has an “SL” model with side tappings like the Munchkins which makes the replacement easier.

dgoldstein

yes, i have ordered parts from Jupiter. No HX available if i break the old one :)

Only one contractor anywhere near me carries IBC.

hot_rod

https://forum.heatinghelp.com/discussion/comment/1859388#Comment_1859388

So I used 55° incoming water temperature, raised to 110, which is about as hot as you could run to a faucet. You could go online and determine the city water temperature high and low probably.

Wintertime water in Phoenix runs around 80°, in Milwaukee down to 35- 37° in above ground water towers.

The only way to get 90% plus is if the boiler is running a low temperature 130 or lower so it condenses. What temperature do you run the Munchkin?

Since the boiler kicks up to 180° for hot water production, 85-87% efficience in that mode.

With a combi the boiler heats water instantly, so no need to calculate gallon like an indirect.

At a 3 gpm flow it could run now until the end of time and produce 110° hot water. It works much like a tankless water heater.

dgoldstein

i think my curve is at 180*F @ 15*F outdoor down to 95*F @ 65*F and then the boiler shuts off if outdoor is greater than 65*F.

You’re definitely selling me the idea of a combi, but i’m still concerned about relying on one unit for all heating purposes.

Alan (California Radiant) Forbes

Then get a heating only boiler and keep your standalone water heater. It's a valid concern.

Long Beach Ed

EzzyT

@dgoldstein where in ocean county are you located? If your on the north side of the county I would come down to take a look at what you have a present you an estimate. I can be reached at 2018878856