• Tag Archives Plumbers Playground
  • OIL HYDRONIC HEATING IS CHEAPEST – For The “Smart” Consumer

    The assumption is that natural gas heating is historically cheaper than fuel oil, witnessed by the continuing conversion rate of oil to gas. The arguments forwarded are several, most notably that “natural gas (and propane) burn cleaner”, are “less expensive” than oil and therefore “more efficient”. All of these points are true in some context, but what is excluded has become significant to the discussion. Namely, heating system efficiencies and fuel cost differentials are narrowing the gap. Exactly how and by how much are the issues.

    An old New England adage comes to mind: “You can either raise the roof or lower the floor” to gain more space. Applied to heating you increase the efficiency of your appliance or lower the cost of your fuel ….. or do both, as we will contend.

    First, let’s begin by “raising the roof” of heating energy creation efficiency. Here again, hydronic (hot water) boiler efficiencies have increased significantly with AFUE Rating increases of over 10% for gases and half or less that for fuel oil. Good numbers at present are 95% AFUE for gas and 87% AFUE for oil “top end” appliances. More specifically these are Condensing Gas and Triple-Pass Oil Boilers. Now let’s get in a little deeper.

    There are three basic elements in any hydronic heating system:

    1. Heating water (a boiler),
    2. Moving heated water (distribution), then
    3. Heating the environment (radiation).

    The contemporary presumption is that the Boiler DOE %AFUE Rating defines heating system efficiency. This is patently untrue on its face. Distribution and radiation efficiencies must be considered to determine an aggregate value. Radiation by type and deployment also affect distribution configuration and complexity. The ensuing “middle ground” between the boiler and radiation we cynically denote as “The Plumber’s Playground”. Herein appears a relative maze of pipes, fittings, circulators, controls and wiring connecting A to B with artistic “free expression”. Thus that new, “pretty piped”, complex heating system despite saving some fuel is an electrical energy hog and a serviceman’s “friend”.

    A hundred years ago we had the Gravity Hot Water Heating System. It was utterly simple, had no moving parts and was operated by manually regulating a fire under the boiler. Powered coal stokers, oil or gas burners were later added with a room thermostat for automatic heating. It was abandoned upon introduction of the hot water circulator and zone valves for installation and operational flexibility and remains with improvements to date. However the natural (gravity) convection attributes of yore are present in degree within “modern” hydronic systems and necessarily controlled with valving.

    Recent introduction of the Delta-T ECM Hydronic Circulator prompted and enabled us to effectively recreate a Neo-Gravity Hydronic Heating Appliance. Functionally it is akin to “putting an ‘Automatic Transmission’ on a Boiler”. Hydronic distribution energy is typically reduced by over 90% of contemporaries. Convective flow is finitely controlled by the Delta-T ECM Circulator like “paddling a canoe with the current” ….. virtually effortless! Coupling to a high-mass, cast-iron boiler to reduce burner cycling and system operating temperature increases boiler AFUE substantially, depending upon the site radiation and heating demands. These claims are substantiated within our U.S.P.T.O. Patent Submission, now affirmed by a recent Notice of Allowance. Canada to follow. Check out our website www.BoilersOnDemand.com for details.

    So, first upgrade your aging, less efficient boiler to a post-modern, high-mass, delta-t ecm distribution appliance, such as ours.

    Second, let’s “lower the floor” by changing your fuel oil buying habits! The “dirty little secret” is that you have options, many options. You don’t just keep buying from “Good Old Joe” because he’s nice and “takes good care of me”. Or pick an oil dealer out of the phone book, your neighbor recommends, or whatever. Not unlike automobile “gas station hopping” the oil dealers have a back door pricing system too, called Consumer Fuel Oil Co-Operatives. They typically aggregate fuel demands of their memberships and solicit seasonal quotations for heating fuel. To give a comparison, we and our participating customers have realized a 25 to 40% reduction over retail pricing in our area (S.W.N.H.) throughout this 2019-2020 Heating Season, for a $25 Annual Fee! Smarten up folks!

    Now, let’s dispel the notion that natural gas fuel is cheaper than oil, using our one-two strategy as detailed above.

    All heating fuels are rated by their “Cost Per Million BTU” as displayed in the NH Climate Audit Heating Cost Calculator, our personal choice of many available. We have used this calculator continuously since 2016 during our appliance development. In all but one winter cycle oil has been a cheaper heating fuel than natural gas. Oil has also eclipsed all other fuels listed for the past two years. This apparent natural gas discrepancy with oil must be first be explained.

    Natural gas and electricity are “distributed” fuels, i.e. they are necessarily delivered through pipes or wires to the point of use. Distribution and service charges are necessarily applied to these fuels, regulated by a State Utilities Commission. Therefore your actual bill is fuel cost plus delivery charges. Dividing the fuel cost into your total bill defines your Service Burden, expressed as multiplier of 1.x to 2.x. Our local multiplier is typically just over 2 at present. Therefore the Natural Gas Cost Per Million BTU must be multiplied by your Service Burden to obtain your true fuel cost.

    Oil and LP (Propane) on the other hand are liquid “delivered” fuels. You pay upon delivery and they are dropped into your oil or gas tank or as gas bottles in your yard. Similarly with the solid fuels: coal, wood & wood pellets. No additional charges apply. This distinction is very important.

    Playing with the Heating Cost Calculator, let’s load in 87% for oil & 95% for both natural gas & propane per prior. Load in $1.586 per gallon (our current “Co-Op Price) for oil & press “Recalculate”. Now using a side calculator multiply your natural gas price of 8.74 by your Service Burden. If its currently over 1.505 oil wins. (BTW – Pity that poor propane guy!)

    If you want to extend your heating calculator play time, increment the item cost values for coal, wood & wood pellets until you equate each to $13.15 Per MBTU. This is the item pricing equivalent to oil heating. Great stuff to needle your neighbor who’s “saving money” while trying to keep warm with solid fuels. Of course avoid that Old Yankee that cuts all his own wood “for nuthin” and massages his woodpile year ’round. “Heats ya twice, ya know.”

    It must be added that Condensing Gas Appliances are significantly costlier to install with reduced economic lives than cast-iron boilers.

    The Heating Blog on our website offers a wide array of related heating subject articles.


  • DELTA-T ECM HYDRONICS – Redefining “The Plumber’s Playground”

    Hydronic heating comprises warming water as a medium, moving and expending its energy to warm an environment. Thus we have boilers as heat generators and radiation to convert heated water into warmth. Between these we must distribute our medium via pipes, pumps, valves and controls to meet heating demands.

    Basic hydronic system design rules of course must apply, but by and large the final product interpretation has been left to the tradesman/installer. This individualization provides a very attractive latitude of self-expression. Like an artist painting on a new canvas individual skills, styling and practice all comprise the final “picture”, with the author’s “signature” applied. Based upon our field observations we have come to refer to hydronic distribution in particular as “The Plumber’s Playground”, and with no apologies offered.

    Unfortunately the Laws of Physics apply equally to hydronic system installations as to any other enterprise. Therefore that maze of pipes, valves, circulators, controls and wiring evidenced in a “plumbers playground”, no matter how pretty, daunting or impressive is unnecessarily complex, costly and under-performs. In fact any system installed within the past three years or more not employing Delta-T ECM Hydronic Distribution Technology specifically is woefully under-performing!

    The Heating Game has changed, led by the Taco® Delta-T ECM VT2218 Hydronic Circulator and its supporting Taco® Zone Sentry Valves. We refer to it as “The Hydronic Revolution”, as it truly is! These two (2) devices, properly applied, can and do dramatically simplify the complexity and content of a conventional hydronic heating system. Again, properly applied and supported by contemporary control systems provided by an “Intelligent” System Aquastat with idealized piping (plumbing) can further enhance performance, as our work has evidenced. Our development efforts and observations are reflected within the remainder of this presentation.

    The Delta-T ECM Variable Speed, Intelligent, Multi-Temperature-Sensing Circulator is a marvel of applied technology. Its ability to sense, measure and maintain a preset temperature differential in a hydronic circuit virtually optimizes heat transfer efficiency in a single, automatic step. Further being able to accommodate varying demands from multiple zones (circuits) virtually seamlessly as we have evidenced places it as the heart of any hydronic system. Using an automotive analogy we slogan that we are putting an ‘Automatic Transmission’ on a Boiler, but doing it hydronically.

    Now pair this Taco® Delta-T ECM Circulator with a compliment of their Zone Sentry® Zone Valves and you dramatically reduce energy consumption while gaining some further fuel efficiency. As Taco® promotes we are seeing distribution power consumption drops to 11-13 watts and in another instance to 8 watts during normal operation! Compare these with 80 watts for a single Taco® 007 and 21 watts each  for a Heat Motor Zone Valve. (The Zone Sentry® uses 11 watts, and then only in a brief actuator “charging cycle”.) Hydronic heating system power consumption is virtually never considered in design, but it should and furthermore must be!

    Piping is the pride of any plumber (ourselves included) yet in so being can become a detriment to system performance. To this point we offer that hydronic convection (the natural attribute of heated water to rise, and cooler fall) is not considered as a positive contribution to system performance, but an attribute to be controlled. As we have witnessed in our design effort however, natural convection is a measurable asset, particularly when configuring piping and placement to maximize its effect. Near-boiler piping, to employ the trade term, is crucial to maximizing hydronic performance. Compacted packaging of correct pipe sizing and layout close to the boiler displays great natural (non-powered) circulation that may not only supplement but also heat at reduced levels. We had an early Delta-T Circulator failure on one of our “beta” installations that was not discovered for an estimated 2-3 days! How’s that for convection — like “paddling your canoe with the current”.

    When you fully integrate the “intelligent” Delta-T ECM Circulator, Zone Valves and Aquastat with idealized convection you come to the conclusion that hydronic system installation is no longer a process, but functionally becomes an Appliance. Our resultant “package” is contained within its boiler footprint plus minimal rear piping space. A designer need only define system capacity, number of zones, fuel type and exhausting to define the “appliance”. Further, the application lends itself to modularization, and thus to versatility by default. Not only do we significantly reduce the material content of a system, but its labor content and installation time as well.

    Now there is both a trade and consumer option, a virtual Hydronic Heating Appliance with a fixed cost and defined, superlative performance. Our work to date has been developing a “Package Delta-T ECM Hydronic (Oil) Heating System” that achieves its higher performance by incorporating Delta-T ECM Hydronic Distribution Technology with a high-mass, lower operating temperature boiler for optimized performance. But also recognize that Delta-T ECM Circulation will work on any fueled hydronic application, putting an “automatic transmission” on ANY boiler. This obviously reduces the size, content and complexity of the “Plumber’s Playground”, but to a net performance advantage in doing so.

    To summarize, a “Hydronic Heating Appliance” is in our near future, defined by technology and necessitated by the market, like it or not. Its Performance Specification will virtually determine system performance, unlike the potpourri of present practice. Our publicized contributions are documented on our website www.BoilersOnDemand.com.  Please note that our current and following product offerings are under Intelligent Property Protection (Patent Pending). We look forward to “Boilers On Demand” in the new “Plumber’s Playground”.


  • SIMPLE, DURABLE, EFFICIENT FHW HEATING ….. PERIOD!

    Our Motto is“Simple, Durable, Efficient FHW Heating ….. Period!”. Boilers On Demand LLChas achieved this seemingly noble objective by fully integrating Advanced Taco Delta-T ECM Hydronic Distribution Technology into Forced Hot Water (FHW) Heating . The unstated result of our“Convection Enhanced Delta-T ECM Hydronic Heating Appliance” (Patents Pending – USA & Canada)development is it being highly cost-effective as well. Can we “have it all”, so to speak? Let’s look at our effort in further detail …..

    Hydronic (FHW) Heating to the layman and consumer has always had a certain mystique, evidenced by witnessing a tradesman or plumber configuring a system, piece-by-piece into a seeming maze of piping and components. The results vary from the mundane to aesthetically impressive, but we must realistically note in fact that the hydronic performance of any system is less than ideal. The residential and light commercial heating markets in particular have not had the tools nor the general expertise to optimize a hydronic heating installation. Consequently the end user has suffered with an over-installed, under-performing, energy-consumptive system over its lifetime ….. knowingly or not!

    Note: We can’t excuse our like personal participation for now sixty (60) years in hydronic heating. Our guilt is shared ….. but no longer!

    Now a true “hydronic revolution” is upon us, not yet generally known and even less appreciated, nor applied. Hydronics have thankfully been somewhat forgiving to all of us applying it, but now there’s a new day, and a new benchmark.

    By explanation, there are three (3) basic elements to hydronic heating: Energy Creation, Distribution and Radiation. Put more simply:

    1. A Hydronic Boiler to create energy by burning a fuel, as efficiently as possible.
    2. Moving (distributing) heated water to points of use with “pipes and pumps” (circulators).
    3. Warming an environment by passing air over hot piping, as simply and effectively as possible.

    We have progressed quite well in creating and utilizing energy via boilers and radiation, but that is where it has stagnated far too long. Given the limitations of fixed or selectable speed circulators and valving we have managed without addressing the true potential of improving hydronic distribution efficiency to complete the heating equation. The intelligent, variable speedDelta-T (ΔT) ECM VT2218 00e Series Circulatorby Taco Comfort Solutions® has changed it all ….. and none too soon!

    We have been experimenting with Taco® Variable Speed Delta-T VDT’s, “BumbleBees”, Viridians and now 00eSiries ECM Circulators for years, utilizing them as direct substitutes for their fixed-speed predecessors. They have worked particularly well as radiant zone circulators as our fellow tradesmen have also discovered. The Taco BumbleBee® in particular has gained trade notoriety both by its appearance and performance. However, our personal technical efforts have gone well beyond the obvious in pursuing a dedicated boiler system circulator application. It has neither been promoted nor seeming anticipated, yet its implications are very significant when achieved.

    Utilizing a Delta-T, and in particular an ECM (Electronically Commutated Motor) based circulator as a single, dedicated system hydronic “distributor” offers near-ideal efficiency potential. We slogan it as“putting an ‘Automatic Transmission’ on a boiler”. It greatly simplifies both near-boiler piping and control complexity, but must necessarily possess several operational attributes:

    1. First and foremost is reliability! A dedicated (single) system circulator failure is a potential “show-stopper” after all.
    2. Performance Flexibility. It must adapt to and accommodate all system energy demand patterns with minimal, if any effect.
    3. Accommodate an Indirect Water Heater as a prioritized and an incrementally higher energy demand accessory.
    4. Significantly improve system efficiency and performance while reducing energy requirements, both fuel and electric.

    Zone Valves are a necessary compliment to manage individual zone demands when using a single circulator. New generation valving and in particular the Taco Zone Sentry® Valve provide outstanding performance and value with self-diagnostics. The “Zone Sentry” in fact delivers three times the heating capacity of its popular “Heat Motor” predecessor, and uses dramatically less power. Combine these with its physical packaging attributes the “Zone Sentry” provides a unique configuration opportunity further addressed in this writing.

    The hydronic distribution function is composed of two elements:

    1. “Near-boiler piping” as generally referred includes circulators, valves, air elimination and expansion devices that prepare and present heated water or “hydronic energy” to points-of-use.
    2. Distribution piping that extends and presents this heated water energy to radiation components.

    We offer that considering these two distribution tasks without differentiation or distinction is fundamentally flawed, and yet is standard trade practice. As initially stated, Delta-T Distribution Technology changes this assumption, and dramatically! Consolidating hydronic flow within a single, intelligent system level circulator packaged with complimentary, intelligent zone valves packages into a true, efficient FHW Heating Appliance. Further, “hydronic convection” (gravity heating), the natural attribute of heated water to rise and convect within distribution piping is idealized as well. Witness the need to install “flow-check” valves in conventional systems piping, into circulators or using properly sited zone valves to control convection (gravity) heating. By incorporating natural convection total circulation energy is measurably reduced beyond that of Delta-T. A simple analogy would be “like paddling your canoe with the current, rather than against it”.

    Hydronic convection performance is at the core of our Proprietary Near Boiler Piping System. Included as a standard, recommended option for idealized system and DHW (domestic hot water) creation efficiency is an Indirect Water Heater(the HTP SuperStor Ultra Series). Close-coupled within our near-boiler piping, its integrated supply architecture becomes a physical, gravity flowing extension of boiler capacity, particularly in circulator fail-mode operation. Yes, we had a “fluke” 1st Generation Taco Viridian® VT2218 failure on our “Beta #3” site that was not discovered for an estimated 2-3 days of heating operation. DHW generation was never affected!

    Ideally complimenting our hydronic system is the highest-mass boiler for its rated output (the Weil-McLain UO Series), extending system energy storage capacity and potential fail-mode convection performance. Its supply and return rear porting compliment near-boiler piping by compactly and efficiently packaging all hydronics within its footprint plus an approximate 1 ft. rear piping and exhausting space. Adding the Indirect Water Heater uses under 12 sq. ft. of combined space, up to 2/3 less than a typical currently installed system while reducing system valving and near-boiler piping by up to 1/2. Integrating with domestic all-steel piping, malleable fittings and brass/bronze valving compose a free-standing system architecture of innately superb strength, chemical resistance and field proven longevity.

    Now applying our paralleled “High-Tech” Manufacturing Process expertise to Hydronic Heating, we have modularized, value engineered, methodized and tooled our Delta-T ECM Hydronic Heating Appliance to include several additional components in our Intellectual Property Protection (Patent Pending) Submission. Our cooperating customers on multiple “Beta Sites” are also providing us valuable data to optimize our system design and performance with the goal of providing an unbeatable cost-performance product.

    Taco Comfort Solutions® publishes that its Delta-T ECM VT2218 00e Series Circulator provides up to 15% fuel and 85% electrical power reductions in applications. We certainly concur! Our dedicated VT2218 system circulators are using 8-13 Watts in heating maintenance mode. Cold system warmups begin at 25-35 Watts (half the rated power) then reducing toward acclimation temperatures.

    At the extreme of our experience is our “Beta #1″ Site upgrade, badly mis-piped with three hidden, seriously undersized 1/2” radiation zone supplies & returns that exhibit high head pressures (obviously). A pre-existing integral IWH is also under-sized piped, adding to delivery issues. Yet, this system cold starts @ 65 Watts, decreases rapidly to 35 Watts, then slowly acclimates to 22-25 Watts running. (A single Taco® 007 draws up to 80 Watts by comparison. It had four operating three heating and the IWH zones.)

    Additionally by using the High-Mass Weil-McLain UO Series (Oil) Boiler(s) we see system operating temperatures lowering to 132-140º F, regulated by its integralHydrolevel “Fuel Smart” HydroStat® 3250-Plus Aquastat. System demands are readily “cushioned” by the thermal mass provided in the total system architecture. It responded very positively to the prior noted prototype system circulator failure, ramping up system temperature toward maximum with zone duty cycle duration detection & response, maintaining radiation heating in degree. Boiler burner cycles are infrequent and brief, further reducing equipment maintenance levels while extending system operating life.

    We have more recently offered the appliance-specific Carlin EZ-PRO Gas (NG&LP) vs. the Beckett NX Oil Burner in the Weil-McLain UO Boiler. Now it’s a Universal Hydronic (FHW) Heating Appliance! Change fuels ….. swap the burner only!

    Total Hydronic  (FHW) Heating System Efficiency is  the AGGREGATE  of Boiler AFUE, Delta-T ECM Hydronic Distribution & Radiation Efficiency Gains! We further claim that the reduced operating system temperatures and hence stand-by losses of the very high mass Weil-McLain UO Boiler further increase overall efficiency. Thus we can confidently claim the highest efficiency heating system available!

    System Comparison

    “Conventional” FHW Heating System         vs.         The Delta-T ECM Hydronic System

     

    Identically Specified 100KBTUH, 2-Heating Zone + IWH, Oil-Fired Systems

     

    Attribute"Conventional" System"Delta-T" SystemComments
    Boiler TypeWelded Steel Plate (Example Unit)Cast Iron "Triple-Pass"15 years +/- vs. 30 Years +
    Boiler Weight270 Lbs.625 Lbs.Very High Mass - Durability
    Oil Burner TypeVarious OfferedBeckett NX (Pressure-Fired)Flexible, stable operation
    Gas Burner TypeFixed, Appliance-SpecificCarlin EZ-PRO (NG/LP) (Pressure-Fired)Appliance-Specific Interchange
    CirculationMultiple Fixed Speed Circulators onlyA Delta-T Variable Circulator w/ Intelligent Zone Valves>/ 15% Fuel Savings
    >/ 85% Electrical Savings
    Piping/FittingsCopper (Typically)All Iron & Cast ConstructionSuperior Strength/Durability
    Indirect Water HeaterVarious Mfrs. & TypesAll Stainless Steel OnlyA Lifetime of Service
    Floor Space UtilizationInstaller-dependentOptimized Package DesignMinimum Space Requirement
    Energy PerformanceInstaller-dependentOptimized Energy DesignPeaked Hydronic Efficiency
    Component SourcesU.S./Foreign Mix (Typical)"All-American" (US/Canada)Quality and Serviceability
    Installed Cost (Oil example shown)"Over $10,000" (Oil, as shown)$7,000 (Oil, as shown)Price, Performance, Value

    To Summarize:

    Taco® Delta-T ECM Hydronic Distribution changes everything! The “Plumber’s Playground” of conventional, inefficient hydronic distribution piping “free expression” is gone as well! We must now look at Hydronic (FHW) Heating in totality, no longer as a an aggregation and assemblage of parts by personal preference. Technology has provided we heating guys with some new working tools. Let’s learn how to use and apply them well!

     Author’s Note: Updated 10/01/2018


  • HIGH-MASS VS. LOW-MASS BOILERS – The Arguments

    It ultimately comes down to economics, as do most things. The current trend is to market low-mass (light-weight) boilers against traditional heavy, high-mass cast-iron boilers. However, there are non-publicized risks involved that must be assessed and quantified.

    New gas-fired appliances in particular have a technological efficiency milepost that must be considered. Specifically, the traditional tube/ribbon gas burner “dry base” boilers vs. the new condensing technology based low-mass boilers. They have a significant energy efficiency increase of 10+% in AFUE Efficiency Rating. Along with this however is a marked increase in appliance costs and operational risks — both quite important, yet never publicized!

    Stainless steel heat exchanger condensing gas units are the most popular and have been doing reasonably well service-wise. Cast aluminum heat exchanger units on the other hand where supply water pH (acidity) has not been addressed at installation or in operation have had issues, to which we can personally attest. Given this reservation they have also performed reasonably well. Being quite sophisticated control-wise, one has to admire the engineered system integrity of condensing gas systems. They certainly do flag service and maintenance issues with their sophisticated sensor complements!

    However, a disturbing pattern is emerging and the alarms are sounding in the trade journals and forums. Premature welded stainless heat exchanger leakage failures are being reported, some even “out-of-the-box” or within weeks of installation. An installed system operating life of 15 years or less is being reported in trade journal articles. The British Market Experience is much deeper and lengthier than ours and their forums are full of user complaints of premature failures and high maintenance costs. Reported system economic lives are commonly less than 10 and up to 15 years on “upscale” products. Cast-iron boilers have been effectively regulated out of the EU market. Do we have a similar lesson coming?

    The common cause of failure for all condensing boilers should be water condition issues, but it’s also become manufacturing process integrity in some cases. Regardless, manufacturers are countering with stringent water condition qualification requirements within their typically 10-Year Pro-Rated Warranties. Not only do water conditions have to be measured and recorded at installation, but subsequent annual service procedures must re-qualify and record these values. Violate your water control guidelines and void your warranties!

    Oil-fired appliances on the other hand are a different animal, with combustion energy containment and management paramount in their design. Heating oil has over 60% more energy content per gallon than gases and can’t be technologically “modulated” (vary the firing rate) as with a gas appliance. Adjusting the output of an oil boiler is done by managing system temperature and/or by utilizing multiple boilers (MBS Systems) in larger installations. Therefore the oil boiler must be designed to perform at its maximum firing rate and within its design parameters. This is typically accomplished by using a cast-iron heat exchanger, and has been the norm for the past two hundred years!

    Let us first disqualify any “dry base” welded-steel-fabrication (oil or gas) boilers from this discussion. Their poorer field performance history in both thermal efficiency and longevity are well documented and recognized. They are sold on price alone. If you have one, you won’t have it for long — unless you were born under a lucky star! (They now barely meet D.O.E. Energy Star Ratings as well, and we hope for not much longer.) Particularly disturbing to us is the poor field history of a nameless, highly publicized “high efficiency” gas-or-oil welded plate construction boiler. Their factory service record as emoted both directly by us, our trade service collaborators and their customers is damnable! Independent servicemen hate to touch them. Parts are product-specific, pricey and their eventual structural fate is predictable. We regard them as a “black eye” upon our industry. Beware of the sales pitch and do your homework! Always get customer referrals at a minimum (including for ourselves)!

    The “wet base” full-combustion-containment cast-iron oil boiler is the industry standard, with a solid performance history. They do however differ by both manufacturer and specific model design attributes that may affect life performance. If your oil boiler does not last at a very minimum 30 years or more, something is very wrong. We have replaced 100+ year old cast iron boilers with still beautiful castings, but you just couldn’t afford to feed them! You are more likely to see a cast-iron boiler section seal corrosion failure in particularly older units or hard-freeze icing fracture neglect than a “worn-out” boiler. Either situation is economically catastrophic though, requiring unit replacement.

    The high-mass vs. low-mass oil boiler argument ultimately comes down to design parameters, material selection, application integrity and its performance under field conditions. The design safety factor of any cast iron boiler can be readily extended by simply providing more iron and more water capacity. “The more it weighs, the longer it stays” – our poor poetry. Works every time, but potentially adds cost to the boiler — as it should.

    We must now extend the preceding arguments to contemporary oil & gas appliance issues. There are three emerging problems well documented in Heating Trade Publications that must be addressed:

    1. “COLD-SHOTTING”. A trade term that describes the condition where cold water is introduced into a hot boiler and thermally “shocks” the heat exchanger metallurgy. Single or cumulative events can result in catastrophic metal fracturing, seal and/or weld joinery failures. The “solution” is the additional piping and installation of a Boiler Return Water Temperature Control Valve to any condensing or low-mass boiler system. This is not an issue with a high-mass cast-iron boiler, nor has it ever been. Please note that Delta-T ECM Hydronic Distribution Technology properly applied will also negate this issue altogether.
    2. MAGNETITE ALLEVIATION. Magnetite is a magnetic, accumulating ferrous (iron) oxide (rust) present in boiler and supply water and attaches itself to internal boiler components, reducing in particular circulation efficiency. It has virtually never been an issue in a cast-iron (a naturally magnetite scavenging material) boiler, but here it is with very low iron content condensing systems. It can only be addressed with an integral, full-time Magnetite Filtration System – a significant initial cost and recurring maintenance additive.
    3. HYDRONIC DISTRIBUTION. Contemporary practices of near-boiler and distribution (to radiation) piping are excessive, unwarranted and inefficient. (We refer to this as “The Plumber’s Playground”.) The seemingly excessive piping and controls witnessed in new installations are so, REDUCING system efficiency while increasing distribution power demands. Low-mass and condensing boiler systems are disproportionately affected. Again, correct application of Delta-T ECM Hydronic Distribution Technology is a must for overall system performance.

    If you’ve read from our “Heating Blog Library” on this site, you would certainly qualify us as “High-Mass Boiler” advocates. We have additionally optimized our system design and performance by fully incorporating “Delta-T ECM Hydronic Distribution Technology”. It smooths hydronic system thermal demands while significantly reducing operating costs. We slogan this as: “Putting an ‘Automatic Transmission’ on a Boiler”™ — to use an automotive analogy. In fairness this technology would certainly be very beneficial when applied to any low-mass boiler! In fact we consider it a prerequisite in any low-mass boiler installation. Please reference our new Packaged ΔT ECM Hydronic (FHW) Heating Appliance™ (Patents Pending – USA & Canada) on this site, interchangeably fired by OIL or GAS.

    Considering the aforementioned, we much prefer high-mass boilers with their “thermal damping” and reduced cycling characteristics. More iron mass and greater water content equals less burner cycling and ultimately longer component life. We have noted in fact (although we don’t necessarily advocate it) that ultimately a boiler maintenance cycle is now more dictated by the quality and amount of fuel oil passed through our Weil-McLain Ultra Series Triple-Pass Boilers than calendar cycles. Their heat exchanger passages are very open compared to prior generation two-pass units. Combined with the combustion quality of the Beckett NX Burner you generate very little ash accumulation. The same cannot be said of a nameless foreign boiler that seems to have high ash generation and more frequent maintenance calls. (We refuse to service them, by the way — hire the mechanic with that “Mercedes”.)

    TRY THIS: Divide the Cost of a Boiler by its Shipping Weight to determine its approximate the Cost per Pound. The Weil-McLain UO is 1/2 to 2/3rds the Cost-Per-Pound of ANY equivalent U.S. or Foreign Boiler! Just what are you buying – durability or ….. ???

    Summarizing, weigh the operating characteristics of your particular hydronic system application before you select any boiler. In particular look at an intelligent hydronic distribution option such as the Taco® Delta-T ECM Distribution System. Just “plugging and playing” a low-mass boiler into your system may not play too long, nor too well.

    Additionally, a very timely read is our commentary on the just published 2019 Annual Boiler Report. “Reading between the lines” we extract the admonition by several manufacturers that despite their pursuit of highly engineered condensing product offerings, a well configured cast-iron boiler system is still economically favorable. It appears, as we advocate, that a proven high-mass, triple-pass cast-iron boiler system fully integrating Delta-T ECM Distribution Technology prevails. The resultant is “SIMPLE, DURABLE, EFFICIENT HYDRONIC (FHW) HEATING ….. PERIOD!  Judge for yourself …..

    (Please refer to our other blogs and appropriate external sources for detail related to this discussion.)

    Updated: 04/03/2020 PDM, Sr.