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    Our singular observation in over 50 years of hydronic (FHW) heating systems installation and service is this: Given any similar application, no two heating systems are configured the same, nor do they consequently service the same. Need they be? We argue that they definitely should be alike for both operational and service efficiencies.

    The impairment to maximizing hydronic efficiency and service lies within the heating market itself. Manufacturers supply components and installers apply them to the customer application employing their accrued experience. The obvious result is the installation variations we observe – “the good, the bad and the ugly” to apply the popular quotation.

    The problem is that even the good is not good enough efficiency-wise, and the installers get little help from their component suppliers, representatives and technical services in this regard. Specific to hydronic boilers, the “building block” of all FHW Systems, the manufacturer provides a generic installation guide with plumbing diagrams and wiring schematics that cover all the bases. No effort is given to efficient component sizing, placement or utilization. Much like an artist that is given a clean canvas with an image theme, the installer creates his own picture as he sees it.

    Ironically, there is an innate need for plumbing and heating guys to paint their own canvas. The daily tedium of fixing “leaks and squeaks” gets old very quickly. The opportunity to become creative by building a heating system on-site and making it look seemingly neat and pretty is a strong draw, not to mention a great payday as well. LEGO’s for Big Kids! Problem is, the customer pays for it up front, and continues to pay over the lifetime of the system in fuel, maintenance and operational costs, knowingly or not.

    From an engineer’s perspective the solution is quite simple, a designed and configured PRODUCT built specifically for the application. The quandary however is: How can you possibly accommodate so many applications and individual variations? There is seemingly an endless possibility of pipes, circulators, controls and valves to idealize an application. This has been the traditional dilemma — until recently. Technology to the rescue!

    Hydronic systems are undergoing a true design revolution with the development of “smart” circulators and zone valves. The combining of these reduces virtually any common residential or light commercial hydronic application to a single circulator and compliment of zone valves to suit. The resultant is a very efficient, flexible and yet simple system. We strongly recommend viewing our companion blog THE HYDRONIC REVOLUTION – THE INTELLIGENT DELTA-T CIRCULATOR FHW SYSTEM for further descriptive and technical details.

    Now to define a typical residential or light commercial system you only need to:

    1. Calculate the total heat loss of the structure.
    2. Specify a hydronic boiler and fuel type with suitable capacity.
    3. Select either a natural draft or forced exhaust venting.
    4. Qualify the use of an indirect water heater, if applicable.
    5. Determine the number of heating zones and their respective supply and return points.

    Note: These comments apply only to a Hydronic Boiler Packaged Product. Heating distribution compliments and completes the system, either as a new or in a replacement application.

    There are currently, to the best of our knowledge, no pre-built, assembled FHW Boiler Package Products applying the latest technologies, assembly methods, materials and logistics to support this emerging market. We are defining the attributes of this market to be providing:

    1. Hydronically optimized boiler package providing exceptional performance.
    2. Intelligent, ideal energy delivery and control.
    3. Complimentary supply zone distribution.
    4. Complimentary zone returns with service enhancements.
    5. Quick, simple on-site preparation and fitting.
    6. Ideally, availability on-demand.
    7. Expedient delivery to site, as required.

    Given the attributes and performance of this product, it will lend itself to service ease by any reasonably skilled personnel. The challenge remains to break the customer from the current norm of “one-stop shopping” for heating installation and service, the intent of this writing. It is only by providing and displaying the performance of such a product will we break the status quo — for the benefit of the consumer, and as an asset to the installer as well!

    We (Mercier Engineering) have participated concurrently in both high-technology manufacturing and the heating trades for over fifty years. An opportunity is now provided to us to participate in developing and marketing this Hydronic Boiler Product. Our career skill-set strongly compliments this task and thus we will be introducing a series of products to develop this emerging market.

    Please follow us on our website: www.BoilersOnDemand.com

    Our “Mission Statement” therein defines us and our goals..


    Finding and selecting a serviceman for your gas or oil heating system is not a simple task. Merely calling up your fuel supplier to send someone over or asking your work associates whom they use from our experience will not usually get it done. Neither will shopping the Services Offered sections of Craigslist, Freebie Advertisers or local Newspapers for the $99.95 Annual Cleaning Special do it. You simply have to do your homework.

    Your goal should be to engage a serviceman who knows your particular system — in its entirety! After all, unless you live in a Condo Complex or Tract Development the chances of a reasonably generic heating system is minimal. Most heating systems evolve, driven by upgrades to the central heater, fuel changes, expansions and adaptations to the structure and so on. So no two systems can therefore be identical and all have peculiar deficiencies.

    Let us first address oil burning equipment. The argument can and should be made that there are only a few oil burner variations in common usage, predominated by the American-made Beckett, Carlin and occasional Wayne Burners. The European Riello is also encountered, but far less often. Therefore selecting a serviceman who knows how to swap nozzles, filters and tune these is all you need. WRONG! There is no “Jiffy Lube” heating analogy to oil or gas maintenance.

    Referring to our other blogs on heating system upgrades and efficiency we must emphatically reiterate — that efficiency report card you get from a serviceman is BURNER EFFICIENCY, NOT SYSTEM EFFICIENCY! It only documents the fuel combustion quality and NOT the heat energy conversion and transfer efficiencies of your system. System efficiency comprises other factors, particularly exhaust temperature and heat exchanger performance. This is why a Heating Appliance receives an “Energy Star Rating”, not a burner.

    With gas combustion equipment the variations particularly within the newer “condensing” system technologies are more pronounced. Manufacturers have developed similar but more unique methodologies that differ also in sensory and control applications. Gas equipment tends to necessarily be more sophisticated and “intelligent” than oil to achieve superior “Energy Star Ratings”, but subject to ultimate fuel cost considerations, particularly with propane fuel.

    Now addressing your particular system servicing, the starting point must be knowledge of your particular heating appliance. This can be simply addressed by referring to your Appliance Manufacturer’s Web Site and to their listing of Approved or Referred Contractors. This gives you some surety of knowledge, but not necessarily of comfort in that an individual with personal acquaintance with your system will arrive. Let’s elaborate.

    Servicemen are typically mechanically inclined individuals that have acquired knowledge and aptitude with heating systems. This is typically attained via journeyman or apprentice training within a trade organization, and prevalently within a fuel dealership or organization. The fuel dealers in particular become “training mills” for servicemen, but prompted by market competitiveness subsequently “spin off” most of their finest as independent servicemen.

    Within a Manufacturer’s Approved or Referred Listing find the local independent serviceman. Let’s face it, he’s flying solo and doesn’t have the luxury of organizational protection. He has to perform or not eat regularly. There is similarly no significant correlation between his performance and the appearance of his vehicle and advertising in our experience. Our only caution is reflected in our prior blog “Plumbing Guys Plumb, Heating Guys Heat” wherein the dedicated heating professional seems to be the most effective performer, overall. Similarly be especially wary of the TV Advertisers! There are just too many complaints of shoddy workmanship, pricey “bait and hook” complaints on these Plumbing and Heating “entrepreneurs”.

    Test your prospective serviceman on a preliminary visit. He should not only be familiar with your appliance, but offer observations related to system components, performance, serviceability and quantify prospective improvements. Particularly solicit opinions related to your heating distribution (ducting, piping, radiation, etc.) and boiler domestic hot water generation where applicable. If your system is say 15 to 20 years old, expect a suggestion to replace particularly the gas appliance, but make him quantify it!

    Now solicit another serviceman and repeat. Compare notes.

    After your selection has serviced your system, measure his performance particularly in respect to service calls. They should be minimal and not repetitive for the same symptom(s). Cut a little slack on ignition and control inter-dependency issues — but only on two calls and how he treats the situation. Otherwise, go shopping again. The successful independents typically have excellent diagnostic capabilities, low service call occurrence and a larger clientele.

    Again, refer to our other blogs for background in assessing your serviceman. Good hunting.


    You have doubtless noted the “Plumbing & Heating” Logos on Trade Vehicles. Both disciplines are related, specifically to FHW (Forced Hot Water – Hydronic) Heating Systems, but not necessarily synonymous. They share similar tools and some materials, but not the same techniques — and it shows!

    At the risk of categorization and classification we can readily identify with surety who installed your heating system, i.e. a plumber, your brother-in-law, a DIY (Do-It-Yourselfer) or a heating specialist. The levels of knowledge, application skills and techniques define the end product, and its net performance and efficiency. To quote the axiom “the devil is in the detail” certainly applies to this observation and how the details affect system operation, efficiency and maintenance.

    Ideally you want a FHW System that is finely tuned for performance, notably:

    1. The highest economically efficient energy producer (boiler)
    2. Hydronic components selected for operational efficiency and life cycle cost
    3. Circulation and radiation options complimenting your structure and lifestyle
    4. Complimentary, efficient DHW (Domestic Hot Water) Generation
    5. Optimized hydronic distribution (piping) and zoning

    Prefacing our remarks, do not do a thing until you know your aggregate needs for heating energy! There is no excuse or recovery for not knowing this up front. A Heat Loss Calculator (see other blogs) is not outside the capability of a homeowner or DIY’er, not to mention the professional. Also the Calculator is a great tool for playing energy improvement scenarios prior to making money decisions. Git-er-done!

    Boiler sizing is usually our first observed misapplication, virtually always too large for the current application. In fairness to the original installer and dating of an aging boiler, the existing structure and boiler inefficiencies were a factor as well, along with over-sizing practices at the time. Unfortunately the resultant of subsequent energy improvements and old indiscretions combine to make the boiler now substantially over-sized and an even greater stand-by loss energy robber. (See other blogs)

    Additionally there are the “plumber’s boilers”, as called in the trade. Same so-so boiler, same techniques for decades. Even this “old dog” has had to learn some “new tricks”. The new Triple-Pass (Oil) and Condensing (Gas) Boilers offer us very efficient new tools — with new rules!

    Near-Boiler Plumbing (includes the boiler and Distribution (Zone) piping) is the next focus area. Indicative poor practices are:

    1. Bushings in boiler supply and return outlets, reducing outlet piping sizes at the peril of high stress and corrosion prone fitting failures at the boiler. (We use Heavy Series Nipples and Reducing Elbows, Tees or Couplings to avoid this structural risk.) Such failures are so much fun!
    2. Continuously hard-piped (supply and return) manifolds, with too many fittings and no repair or boiler removal provisions. (More fun!)
    3. Extended length manifolds with high cantilevered loads (weights), sometimes anchored to the floor, wall(s) or overhead construction for support. (Here’s our “Compact Steel Hydronic Header” – Patents Pending that addresses this problem)
    4. Poor (or no) manifold flow proportioning.
    5. Lowered return manifold and piping.
    6. Lots of copper piping vs. iron.
    7. Misplaced, excessive or insufficient valving.
    8. Circulation and/or Zone Valve application and placement.

    The added Indirect Water Heater installation is virtually always “hacked”, i.e. however neatly installed it is thermally compromised. Too much, inappropriately sized, and somewhat under-insulated piping usually stretched from existing boiler manifolds contribute to unnecessary seasonal stand-by losses. (Our “Secret”: We “close-couple” Indirect Water Heaters directly to the first-off-the-boiler fittings to minimize heat loss. The system manifolds are unheated seasonally, save a little convective heating under the insulated riser piping.)

    The guy who has to service a boiler knows best where to place service components (water pressure regulator, circulators, valving, relays, service switch or clean-out accesses)! We position all of ours within an arm’s reach for servicing efficiency.

    A point to ponder: Every extra foot of piping, every elbow, foot of water head-height and gallon of water, through every fitting and valve consumes more energy to accomplish the heating task. Distribution efficiency is totally disregarded by every contemporary hydronic (FHW) heating system installer!

    Example: A past “boiler swap” in an apartment house yielded an excess of 35 feet of copper pipe lengths, many shorter “cuts”, fittings, etc. The new Triple-Pass Weil-McLain Ultra Oil Boiler fires @ 70% of the prior 30 year older Weil with new, appropriate wet-rotor circulators uses 40% less fuel and supplies endless DHW through an 80 Gal. Indirect Water Heater. Every little bit counts — and counts up!

    If it’s any consolation, many of the “old dog” plumbing guys are closing out their careers. Now we other “old dog” heating guys that are determined to continue adapting and applying our skills and experience using the new heating tools have our days in the sunlight. Problem is, we have a lot of consumer educating to do. Hope that jabbing our plumbing brothers a bit makes this ever more apparent.

    To emphasize this point look at our Enhanced Convection Delta-T ECM Hydronic (FHW) Heating Appliance – Patents Pending (USA & Canada) and our supporting website www.BoilersOnDemand.com.

    If our fellow “Plumbing & Heating” Tradesmen need assistance in efficiently applying the latest in hydronic distribution technology, perhaps we can help them ….. or you, the consumer directly with America’s First Hydronic (FHW) Heating APPLIANCE™!

    Updated 08/01/2018 P.D.M., Sr.


    If there is anything to promote about a steam heating system is its absolute simplicity, reliability and durability. How many 50 to 100 year old boilers have we pulled that looked half that age and indeed much less? Can’t remember ever replacing a radiator. Fix a cracked fitting once in a great while (usually from someone banging into a radiator), pack a valve stem that is hissing. Usually it is replacing radiator vents that were hit, breaking the mounting stem or that have become stuck over years and the radiator doesn’t operate properly.

    Otherwise it is problems arising from bad water supplies and longer-term neglect that ultimately are the Achilles Heel of “Steamers”. Sludge and sedimentation accumulates untreated and then plugs particularly the return lines and obstructs boiler controls, and in particular affecting water level control.

    By definition, a “Steamer” consumes some water in making steam that must be both incrementally replaced and regulated in doing so. This can be done manually or automatically. The “old timers”, both residential and commercial steamers were replenished manually, hence the occupation “boiler tender” or “fireman”. Fortunately few manual examples remain, but there is yet an issue of reliability that must be addressed with “automatic” water feeders. Specifically the Float Style vs. the Electronic Immersion Sensor Style.

    An undetected and unregulated low water condition under a heat demand condition is the death knell of a steam boiler. Every failed steam boiler we have replaced, some as low as five years old has been “cooked” in heating jargon. The burner kept firing with low water until the top of the boiler castings glow red, then warp, seals fail and finally the unmistakable acrid smell of hot cast iron. This is always catastrophic and the first thing we look for is the reddish, rust orange color and dusting on the top castings. More importantly is why does this always occur with a supposedly “automatic” water feeder, specifically a “float style” feeder?

    The “float style” feeder is easy to recognize, typically an external, black casting extending from the boiler near the water sight glass that indicates boiler water level. Note also that there is also a handle on or very near the device with an open pipe or port used to move water through the float chamber, flushing out sediment and residue. This is a much overlooked feature and maintenance requirement of a steam boiler. READ THE MANUAL — IT MUST BE DONE PERIODICALLY AS STATED! Unfortunately if the feeder is ultimately flushed, even then regularly, the damage may have already been done by the prior negligence. The sure test is to shut off the boiler water feed, drain down the boiler using the boiler drain at the bottom of the boiler until the low water switch cuts off the burner circuit. Refill the boiler “automatically” and verify its functionality. Then repeat the test.

    Alternatively speaking, an Electronic Immersion Probe Low Water Cutoff is a “no-contest” option. Not only does it note low water, interrupting burner operation but can provide additional features, depending upon the individual model such as accurate foaming compensation, “settled down” water level delay measurement before and during operation, water feeder control and control external alarms. On the minus side the immersion probe should be periodically cleaned per the manufacturer’s recommendation. This can be readily done on your service cycle when the technician checks boiler water condition. Note: Many manufacturers now provide the Float vs. Electronic Low Water Cutoff Option in new boiler offerings. There are two (2) major cutoff suppliers, Honeywell and Hydrolevel, the latter being our personal preference. They can and should be upgraded to minimize boiler damage potential.

    Along with this must be considered the external “Automatic Water Feeder” itself. There are again several functional variations offered, ranging from a “dumb” turn-on-turn-off valve to more sophisticated programmable devices that can adapt to any system water usage, condensate return patterns and elimination of the resulting potential boiler “flooding” conditions. We obviously prefer the latter type. It compensates for all conditions during installation and eliminates any unnecessary future service calls. Our personal preference again is the Hydrolevel VTX Series Automatic Water Feeders.

    In conclusion:

    1. If you’re upgrading by simply replacing a steam boiler, specify an Electronic Low Water Cutoff System.
    2. If your existing boiler has a “float style” cutoff — retrofit it to an Electronic Low Water Cutoff System.
    3. In either case, also consider a Programmable Automatic Water Feeder.

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