• Tag Archives DHW
  • NOW A TRUE DELTA-T ECM HYDRONIC (FHW) HEATING APPLIANCE!

    Hydronic (FHW) heating system installations can be likened to creating something with a giant Erector Set™. As a kid, mine came with an electric motor enabling powered cars, airplanes, ferris wheels, etc. Days, weeks and months of childhood imagination and expression ensued. Great memories!

    Now as “big kids” hydronic heating system installations offer us a similar fulfillment of free expression. Within the limits of ultimate system functionality hydronic “artists” can seemingly paint their own canvas while getting paid for it! The question logically arises however as to where are the cost benefits of our efforts? We argue that heating guys are indeed losing direction, both technically and functionally. The adage “Old Dogs need to learn New Tricks” comes immediately to mind, regretfully also being one. It’s not only our innate trade resistance to change but not to think forward in applying what has preceded us ….. beginning with Physics 101!

    Gravity convection was the means of distributing heating water from the Roman Age onward. From the mid-1800’s to about 1930 it was “Queen” Gravity Hot Water along with “King” Steam. However gravity hot water systems required large boilers, piping and radiation sizes. They were slow to react, single-zoned and fuel hungry, whether burning wool, coal, oil or whatever.

    Introduction of the electric circulating pump changed hot water (hydronic) heating forever. Now multiple zones, rapid response through less intrusive radiation and powered burners do it all very conveniently. Gravity is still there, but we have necessarily learned to control it with flow check valves. Apart from the brief and unsuccessful introduction by American Standard of their “Ash Can” Gravity Boiler System in the late 1950’s (our nickname – we were Am-Std Installers back then) FHW has predominated. Circulators began by being placed on the (cooler) returns with flow checks on the (warmer) supplies to control convection. Then circulators moved to the supplies along with the valves. Boilers are now migrating from two-pass to three-pass or condensing types for greater efficiency. That’s arguably been it ….. until now!

    Enter the Delta-T (differential temperature) sensing and managing, ECM (electronic commutator motor) driven Variable Speed Circulator, specifically the Taco® VT2218-HY1-FC1A01 (Current Model). This latest iteration in Taco® Hydronic Distribution Technology is making its inevitable mark on radiant and other hydronic circuits. Its “smart” capabilities are many however, having five (5) selectable operating modes, but we are focused only upon the “DELTA-T MODE” within its appetizing menu.

    We have been experimenting for some years now with Taco®’s prior Delta-T’s and the current VT2218 ECM as a dedicated system circulator, beyond that denoted in Taco®’s Product Brochure. During this process we discovered and integrated differential temperature management with natural hydronic convection (gravity) for an optimized design with superlative results, again well beyond those claimed by Taco®. Multiple “Beta Site” installations have provided us with sufficient data and results to seek “Provisional” and now subsequent “Non-Provisional Intelligent Property Protection” on our:

    ENHANCED CONVECTION, DIFFERENTIAL TEMPERATURE MANAGED HYDRONIC HEATING APPLIANCE (Patents Pending, USA & Canada)

    Quite a mouthful indeed, but place the emphasis on APPLIANCE. You see, delta-t hydronic technology is not merely a “circulator swap” for radiation and energy efficiency gains. It offers additional opportunities in hydronic process integration and management as yet either unrecognized or underutilized. Our efforts fall on the latter, particularly when cooperating with “Mother Nature” by employing natural hydronic (gravity) convection to an operational advantage.

    Falling back upon and employing the principles of “non-powered” gravity heating we optimized a “contemporary” Delta-T ECM FHW System. Utilizing supply and return iron-piping “stacks” and compacted manifolding minimized distribution head losses. Combine these with the thermal storage capacity of mating to a cast-iron high-mass boiler enables a true, free-standing APPLIANCE. Its profile is contained within the boiler footprint plus about a foot of exhausting & piping space to the rear. Modular construction is a natural for hydronic elements as well as system wiring and controls. Module variations to suit particular site and application requirements logically follow.

    Taco® promotes energy reductions of up to 85% and 15% for electricity and fuel respectively by using their Delta-T ECM Circulator Product. We emphatically agree ….. and even more! Measurements on our multiple “Beta Sites” indicated a deviation that was not anticipated. Namely, upon the dedicated VT2218 system circulator achieving preset “delta-t” and stabilizing, the wattage displayed further deteriorated to approximately half this value along with some further speed reduction! A subsequent “Beta Site” circulator failure confirmed our suspicions. First, that failure event was not noticed for an estimated 2-3 days, and then only with a gradual decay in house temperature. The event was camouflaged by an integral Indirect Water Heater (IWH) based domestic hot water (DHW) delivery that was never affected!

    The circulator failure not only quantified the now measurable convection (gravity) heating effect witnessed, but qualified our overall near-boiler piping configuration, purposely designed with a de facto priority circuit for the IWH Option. The latter eliminates the need for that particular optional control feature. Further witnessed on our “Beta” circulator failure was boiler temperature operating near maximum. The Hydrolevel® 3250-Plus Aquastat on our Weil-McLain® UO Boiler logically incremented system temperature upward, attempting to satisfy prolonged zone demand(s). The higher supply/return temperatures and differentials further enhanced convection. The effective 700 pound plus thermal storage mass of our “appliance” also served to dampen the close-coupled IWH zone demands! It is reasonable to presume that the IWH thermal storage would also be “pumped down” during a burner failure, passively prolonging thermal decay.

    Radiation configuration and piping integrity are paramount to convection (gravity) heating effectiveness however. Drawing from over 40 years operation of our personal dual-fuel, fully no-power emergency capable hydronic heating system, we can attest to radiation attribute importance. Simple, well designed serial and split baseboard loops work best. De-aeration is absolutely necessary and system water pressure must be present. Taco® Zone Sentry Valves utilized in our design have a manual open-close feature that can be utilized to regain a heating level upon an actuator failure, as do current flow check valves. (NOTE: You can replace a failed Taco® actuator head on our appliance in 20 seconds – if ever a need!)

    Complimenting hydronic performance is our “Compact Steel Hydronic Header” (Patents Pending) that positions, orients and provides flexibility in both zone and return valve mounting with expansion capability. Placing Taco® Zone Sentries at their minimum (2-3/4″) spacing with wired harnessing eliminates the need of a significant valve or circulator relay expense ….. and with greater diagnostic and system functionality!

    Currently applying our manufacturing process expertise we are projecting the “economies of scale” provided in our construction. The physical modules of boiler, supply and return are configured for capacity/fuel and zone complement and inventoried. A natural and complimentary option of an Indirect Water Heater (IWH) for domestic hot water (DHW) generation falls into this methodology as well. Adding assembly fixtures, applied tools, wiring assy’s, etc. further contribute to appliance value.

    A Hydronic Heating “Appliance” changes everything. The historical loose-piece “process” of hydronic (FHW) installation now becomes a “product” installation of lesser content with higher, predictable system performance and costs. Not just having a stock product that readily configures to the specific requirement, but being available on demand to fulfill both routine and seasonal emergency failures is a valuable resource indeed. Appliance costs and performance are also guaranteed, with all components warranted by their U.S. Manufacturer(s) as with any contemporary installation.

    Our motto: “Simple, Durable and Efficient FHW Heating ….. Period!” sums it all up. Technology has finally caught up with hydronic heating, and it’s about time! The end game after all is providing real value to the consumer, is it not?

    Author’s Note: Updated 01/20/2018


  • “PROGRAM” YOUR INDIRECT WATER HEATER (IWH) FOR SYSTEM EFFICIENCY

    An Indirect Water Heater (IWH) driven by an efficient hydronic boiler is the acknowledged cost-effective method for domestic hot water (DHW) generation. However, installing an IWH as a stand-alone (dumb) heating accessory can limit its potential and in fact reduce your overall annual heating system efficiency (AFUE) in practice. Let’s examine the elements comprising a complete hydronic system and their effects.

    The Indirect Water Heater (IWH) has experienced a renaissance with the availability and effectiveness of modern materials and manufacturing. Specifically Stainless Steel, Super-Insulation and Automated Manufacture provide a superb product-performance package, eclipsing its predecessors and current competition. Even so they are not “cheap” in a monetary sense, yet provide an outstanding service life while maintaining efficiency!

    Referring to our website www.BoilersOnDemand.com you will note that we integrate an IWH into our “Packaged Delta-T Hydronic FHW Heating Appliance” as standard equipment for overall performance. The HTP Superstor Ultra has been our exclusive IWH offering for over twenty years with stellar performance! There are many IWH Products available, even within HTP, but the SSU Series still exceeds.

    Referring to our “Packaged Delta-T Hydronic FHW Heating Appliance” image provided you will note four (4) basic system components:

    1. A “High-Mass” Weil-McLain Ultra Series UO Boiler.
    2. A “Green” Taco Delta-T ECM Circulator immediately above the boiler.
    3. Several Taco “Zone Sentry” Valves near circulator (for IWH) and @ top, center for heating zones.
    4. A HTP “Superstor” IWH, close-coupled to the right.

    As a standard feature on all systems utilizing an IWH as pictured, we provide a SPST (ON/OFF) Switch mounted on and in series with the IHW Aquastat. This allows selective engagement during system set-up, quick start-up, operation and diagnostics. It is visibly evident between the boiler and the IWH, placed for convenience.

    Our “System User’s Guide” refers to the IWH Selector Switch as a means of customer-inhibited operation with a two-fold purpose:

    1. Cycling only preparatory to demand DHW usage such as a dishwasher or shower(s), then “tailing” hot water via additional tasks to efficiently utilize remaining storage.
    2. Turn off DHW during protracted absences such as vacations, etc. while preserving primary area heating without risk or penalty.

    In either sequence boiler temperature is significantly reduced, ultimately approaching area ambient, reducing fuel consumption in the process.

    Using our SPST (ON/OFF) Switch as a junction box we also offer to our clients extension via another switch in series to a more convenient operating location. This is particularly helpful when considering site physicals and customer physical impairments or limitations.

    Carrying this to the next logical level is using at minimum a 1-Day or preferably a 7-Day Programmer, as may be applicable to your lifestyle. Keep in mind though that an IWH Zone uses a “dry” switch, i.e. no power applied, or you will “fry” something (your system aquastat!). Program your IWH Service to compliment your usage pattern for energy savings.

    Then you can proceed into the “wireless”, intelligent world via Wi-Fi Thermostats, Home Automation and the like. Like our “techie” customer on a work assignment in Hawaii who called us to advise he had a heating problem in his seasonal home up here in New Hampshire, the world is changing and beneficial technology is available to us all.

    By becoming “smart”, we can save ourselves a bit of trouble and a little money in the process.

    Author’s Note: Updated 01/10/2018


  • THE DELTA-T ECM CIRCULATOR — The “Automatic Transmission” for Boilers

    After speaking on-site  with a local customer about his system, he inquired as to what else we were doing. A mistake on his part.

    Both of us having differing technical backgrounds I launched into an inspired dissertation of our application of Delta-T ECM Circulation to Residential FHW Heating Systems. Obviously very interested, a running Q & A exchange of increasing technical depth ensued to the point of my noting he was developing that “deer in the headlights” look of incomplete understanding.

    We engineering types have a terrible habit of technically overloading our audiences, not as an “ego-trip”, but to inform as effectively as possible — we think!

    Needing to salvage the situation I paused, desperately searching for that inspired “bolt of lightening” to strike and clarify the atmosphere. By seeming grace, it came immediately! “I’m putting Automatic Transmissions on Boilers.” Yeah”, he responded, “that makes complete sense. Good idea!” Our further conversation became an analogy of FHW Heating Systems to Automobiles, surprisingly clearing our technical disparages. To expound …..

    After all, hot water boilers and automobile engines are both truly “heat engines”. An automobile engine must convert as much fuel combustion energy into mechanical propulsion power as possible via pistons, crankshafts, etc. Less than 60% becomes useful power, the remainder is dissipated as waste heat. The hot water boiler on the other hand necessarily converts its fuel combustion energy directly into useful heat at up to 97% efficiency!

    The automobile uses a transmission to adapt its mechanical power to control vehicle propulsion. A variety of gears, pumps, valves, etc. are used to accomplish this. The hot water boiler conversely needs only to move heated water (via a pump) exactingly to ideally acclimate our heated areas and (optionally) our domestic hot water (DHW).

    The Delta-T ECM (Differential Temperature) Variable Speed Circulator (Pump) is that ideal “boiler transmission” that delivers heated water most efficiently to maintain our comfort. So efficiently does it do so as to reduce system fuel consumption by up to 15% and electrical consumption by up to 85% as documented by Taco, Inc. Published Testing Results.

    No longer is heating system efficiency measured solely (and inaccurately) by the Boiler AFUE (Annual Fuel Utilization Efficiency) Rating, but the aggregate of Boiler, Distribution and Radiation Efficiencies. There are THREE (3) Elements in a hydronic heating system! Just as in Sulky Racing, it’s the combination of the horse, the jockey and the buggy that wins races.

    Even more exciting  is the opportunity provided by the Delta-T ECM Circulator to most efficiently configure a FHW Heating System, which we have done very effectively. Refer to our other, recently published Delta-T Blogs on this site that detail our development, field testing and observations of our systems.

    Our “Packaged Delta-T ECM Hydronic Heating Appliance™” (Patents Pending) exhibits the following attributes in direct comparison to the typical “conventionally installed” system:

    1. Has a higher Combined Boiler AFUE and Delta-T ECM Distribution (System) Efficiency than achievable with any “conventional” system configuration.
    2. Consumes less fuel and electrical power than any equivalently sized system.
    3. Our Integrated Boiler/Indirect Water Heater System occupies 1/3 to 1/2 the floor-space of others.
    4. Our proprietary Fully-Iron & Cast near-boiler piping maximizes durability and distribution performance using fewer materials.
    5. Further combining a High-Mass Boiler with an All-Stainless Indirect Water Heater assures a dramatically projected economic life (30 years or more?).
    6. A truly universal, multi-fuelable Appliance. Just change the burner and not the system!
    7. Provides, Simple, Durable, Efficient and Cost-Effective FHW Heating.

    So yes, we do put “Automatic Transmissions” on Boilers!

    Author’s Note: Updated 07/23/2018


  • DOMESTIC HOT WATER (DHW) GENERATION – YOUR OPTIONS

    We just returned from a hardship “no heat” service call. These folks are obviously up against it economically, as are many these days. However they recently substituted an electric water heater for their boiler immersion coil to generate domestic hot water and hopefully reduce their summer fuel bill. Now they are concerned about the increase in their electric bill as a consequence.

    This brings up the timely subject of options available in DHW generation. Please refer to content in our other blogs, specifically related to energy source selection, tempering tanks and using a Heating Cost Calculator. For the latter we use the NH OEP Heating Cost Calculator at http://www.nhclimateaudit.org/calculators.php. There should be equivalent calculation tools available for your region.

    Heating Cost Calculators don’t lie. They provide a unit energy cost per Million BTU’s for each fuel. You should apply an appropriate AFUE (Energy Efficiency Rating) for your or the best competing appliance by fuel type to get an accurate comparison.

    By calculation DHW heating fuels from lowest to highest costs are: (NH Region)

    1. Natural Gas – Rate factored by 1.5 to 2 for actual billing. (Divide total fuel billing by actual fuel charge for factoring.)
    2. Fuel Oil
    3. Propane
    4. Electricity – Must be also factored for actual billing. Ours is 1.85. (Varies significantly by Provider & Region)

    Note: 1&4 are “distributed fuels”, necessarily incurring varied pipeline and distribution service costs.

    Natural Gas has been historically the most efficient fuel for both heating and DHW generation vs. fuel oil until recently. A very rough crossover is a $45/bbl Crude Oil Price. Local fuel market variations and appliance installation costs must be considered. Propane, a manufactured fuel, is by comparison a significantly higher cost product. This is unfortunate in that they utilize the same appliances (with minor modification) with similar efficiencies. Propane fuel cost is a killer!

    Fuel Oil and Gas Heating Appliances provide the same function, however differing significantly in configuration to accommodate their particular combustion characteristics.

    Electricity despite its extremely high energy efficiency is offset dramatically by unit cost. Electric Water Heaters are enticingly priced, too. Too bad.

    We are considering only the intermittent combustion fuels (oil and gases) in our analysis. The continuous combustion fuels such as wood, coal, etc. suffer by nature to being very inefficient DHW generators. This is not to allow that these fuels fired in boilers can provide seasonal DHW to Indirect Storage Heaters or coupled to a central boiler with an immersion coil. Although increasing in rural popularity, they don’t represent a significant market segment to date, nor likely will they ever.

    Gas and Oil Combustion Appliances are limited to Boilers and Water Heaters. Their configuration options are similar with the exception of the Gas “Demand” Water Heater and are as follows:

    1. A “stand-alone” (dedicated) Oil or Gas Water Heater. These are a virtual necessity when the central heating appliance is Forced Hot Air (FHA). The stand-alone Oil-fired Hot Water Heater has suffered from poorer fuel efficiency by design and has been limited to high demand users such as restaurants, etc.
    2. The Gas “Demand” Water Heater – A unique, hang-on-the-wall device, it stores no heated water but fires only when DHW flow demand is detected. It is very sensitive to water conditions, including acidity, contamination and lower delivery temperatures.
    3. A Central Heating Boiler with an Immersion Coil therein to create DHW.
    4. A Central Heating-only Boiler coupled to an Indirect Water Heater (Super-insulated DHW Storage Tank). Provides higher efficiency in both heating and DHW generation. Significantly increasing in popularity.

    The Gas-fired “On-Demand” Water Heater has a distinct DHW market application, subject to several limitations:

    1. They are “pricey” relative to other options.
    2. Initial DHW delivery is mildly delayed during warm up.
    3. Long cycle demand capacity reduces with supply water temperature decrease (colder water from source).
    4. Annual chemical treatment to control sedimentation is required to maintain performance.

    Note: Both the Gas “On-Demand” Water Heater and Boiler Immersion Coil Systems mentioned can benefit from a “Tempering Tank” placed in line with their water supplies. (Reference our prior blog on these.) It’s a non-insulated accumulation tank that allows water to acclimate to ambient (room) temperature before entering the DHW heating device. Increases heater performance significantly by temperature and delivery maintenance over total cycle demands.

    Otherwise, Indirect Storage Heaters are the path to efficient DHW generation and storage – regardless! They compliment lifestyle variations and usage patterns when coupled to an efficient heating-water-only generating device, commonly referred to as a “Cold Start” Boiler. It fires ONLY when area heating or DHW recovery is demanded. Otherwise they revert toward ambient temperature, saving significant “standby losses” when not in use. There are several options to “getting there from here”, depending upon your situation.

    1. Purchase a High-efficiency “Heat-only” Boiler and Indirect Water Heater as a package and be done with it.
    2. You can convert your existing Immersion Coil System Boiler to a “Cold Start” Type by:
      • Changing your Master Aquastat Control to a “Cold Start” Unit
      • Adding an Indirect Water Heater with its own circulator or valved zone.
    3. Couple an Insulated DHW Storage Tank to your current Boiler Immersion Coil with a POTABLE WATER CIRCULATOR ONLY (Stainless or Bronze) and Temp Aquastat Zone in the loop. Substitute a “Cold Start” Master Aquastat to convert your boiler to a “Heat-only” as in Option 2.
    4. Do Item 3, but convert a good 80 Gal. Electric Hot Water Heater into a Storage Tank. Strip its wiring and utilize the upper, internal Thermostat Switch as a DHW temp control. Note: This last option is the “Cheap Trick”. It costs significantly less to install, despite the pricey circulator requirement. DHW piping is typically run in parallel with the immersion coil with a flow check function.

    Whenever employing ANY Storage Tank for DHW, place a Thermal Expansion Tank in-line on the cold water supply line! Heating cold water expands it, creating pressures well above the supply pressure and potentially bursting the system. This is particularly evident in municipal or well supplies where there’s a check valve in the cold water service. Cheap insurance!

    So, using the appropriate fuel costs from a Heating Cost Calculator and reviewing your current or planned appliances, plan your Heating and DHW Systems together for best efficiency.

    Last Edit: 06/24/2017 pdm


  • ADVANTAGES OF A TWO-TEMPERATURE DHW (DOMESTIC HOT WATER) SYSTEM

    Legally, Plumbing & Heating Technicians are required to set the DHW (Domestic Hot Water) temperature at a maximum of 120 Degrees Fahrenheit at the faucet(s) (taps). The purpose is simple, to prevent personal injury particularly of children and when operating any water tap. It works, but is it ideal for the residential or commercial user? No.

    Like any regulation it has up and down sides. The down side is that some dedicated appliances need higher water temperatures or you pay it back in poorer performance and increased electrical energy costs. Dishwashers and commercial power washers are the primary examples.

    Commercial Dishwashers require a continuous 140 Degrees Fahrenheit supply to assure bacterial elimination and augment the sanitation cycle (electrical enhancement). We have had more than a few instances where clients have not been able to meet State Health Dept. Guidelines. In all cases there was a misapplication of DHW heating equipment involved. Shouldn’t a similar situation exist with residential DHW generation? It does.

    Examples:

    1. Local Dealer installed a Rinnai Demand Water Heater to supply a commercial dishwasher in a restaurant. Rinnai and others supply up to a 120 Degree F output as shipped. There is an internal switch to increase this to 140 Degrees F — and immediately void your Warrantee. There is a product application disclaimer on these and other Demand Heaters specifically excluding commercial dishwashers and other similar applications. Moreover they will not supply the volume of water over time (the Delta-T Problem). The only potential solution is to supply tempered water to the heater (see other blogs), but this can be iffy even for this application.
    2. Area Church installed a gas-fired 40 gallon water heater to supply their commercial dishwasher. Even if you could force the temp up to 140, there is not enough stored and resupply volume to operate through cycle(s). Being a single DHW source in a public structure, then what do you then do about tap water temperatures?

    Now, what about your residential dishwasher? The same process applies with similar results — but you don’t see it readily. That 120 Degree F (at best) water does its thing, but not as efficiently. Your initial wash temperature is low and efficiency suffers. The electricity-sucking water temp coil and sanitizing cycles are notorious energy users. (Look at the Wattage Data on the Appliance Nameplate.)

    The obvious solution in all cases is to supply hotter water to all dishwashers. In one manner or another you must provide a dual temperature source to accomplish this. The techniques vary depending upon your DHW source:

    1. Electric, Gas&Oil-fired and Indirect DHW Heaters – Increase your thermal switch or aquastat temps up to 140 Degrees F (the usual max allowable by design). Then separate your piping to the dishwasher (and other?) and install a good quality Tempering Valve into your other tap water supply line(s).
    2. Immersion (Tankless) DHW Coil in your Boiler – Ideal situation. Tee the output of your coil to dishwasher (and other?) for maximum temperature water. Careful – it is scalding hot!
    3. Provide a separate, high temperature & capacity DHW Heater to suit the particular appliance(s).

    Meanwhile do the “cheap tricks”:

    1. Insulate all your DHW lines from heater to use points, regardless and inasmuch as possible.
    2. Shut off your DHW immersion coil boilers between cycles to save energy during low heating season demands. It only takes about 15 minutes to reheat. Plan ahead.
    3. Open the nearest hot water tap to your dishwasher (kitchen sink?) to get water hot before cycling your dishwasher. This will minimize that initial wash temperature problem in the dishwasher.

    If you should decide to employ high temperature DHW taps for specialized use, do it safely. Secure them!

    Last Edit: 10/10/2012 pdm


  • STRETCH YOUR WATER HEATER PERFORMANCE WITH A TEMPERING TANK

    Water heaters are rated by the number of gallons of water per minute (GPM) or per hour (GPH) that they can raise water 100 Degrees Fahrenheit. This measure applies to all water heaters, regardless of their construction or fuel source.

    So by definition if we can increase the incoming water temperature to our heater:

    1. The output water temperature can be increased (subject to a safe temperature limiting), or
    2. The volume of controlled temperature water output can be increased, and
    3. The total effective capacity of any heater can be increased.

    Domestic water entering your home (or business) is always significantly colder than the heated environment. Thus as an example you must let the water run a while before it gets cold to pull cooler water from the outside the building (underground) water source. The effect is similar with the hot water heater supply piping, subject to the limited water piping capacity within the heated area. When the cooler water reaches the water heater it has to work harder to elevate temperature. Therefore by increasing the amount of environmentally warmed water to the heater we increase performance and save energy.

    Placing a non-insulated water tank between the water service entrance and the water heater we allow a larger volume of water to acclimate (temper) to the ambient temperature at its location, thus a “Tempering Tank”. Its construction and configuration are simple:

    1. A somewhat taller than wide tank with two pipe openings, one near/at the bottom and the other near/at the top. Its interior finish must be compatible with passing potable (sanitary) water through it safely.
    2. The incoming (cooler) water is piped to the bottom of the tank and the outgoing (warmer) from the top to your water heater. Hot water rises and therefore the warmer water stays substantially at the top while the colder replacement water enters the bottom. Water will diffuse within itself, but at a typically lesser rate than used, protracting this effect.

    Practically, any water heater or water storage tank stripped of insulation and being glass, stone or otherwise lined for water cleanliness is suitable. There are other options as well, typically used for well pumps and wet processes. So, look around for an opportunity.

    Note: One point to remember is that the temperature differential and flow of cold water can cause these tanks to “sweat” (condense moisture on the lower exterior of the tank). The simple solution is to provide a larger pan with an inch or so of coarse sand in it under the tank to absorb and then evaporate the condensation effectively.

    Please accept that this is not a cure all for a too marginal heater or a plugging in-boiler or other heater coil. The latter will surely get worse over time, but in the meanwhile helps with comfort while saving energy.

    This “trick” is nothing new. We sometimes refer to them as “Farmer’s Tanks” when found in our older New England Homes. Thank them.

    It’s a great Do-It-Yourself (DIY) Project. So that old electric water heater with the burned out elements that you just haven’t disposed of yet may have some life left in it after all.

    Last Edit: 04/05/2017 pdm


  • BOILER RUNS JUST FOR DOMESTIC HOT WATER – WASTING ENERGY!

    During the heating season, having an Immersion Coil in your Boiler to provide Domestic Hot Water (DHW) makes a lot of sense. You are utilizing the hot water present in your boiler for area heating to additionally provide hot tap water at a very reasonable cost.

    But what about when there is low or no area heating demand? Your boiler is still hot (typically between 160 and 190 degrees F) waiting to provide occasional domestic hot water (at about 120 to 140 degrees F). Meanwhile the boiler stays at temperature, radiating heat into the boiler room and leaking heat up the chimney, neither of which can be utilized.

    A commonly used trick to save energy during the low demand period is to turn off the boiler entirely using the Emergency Switch (usually located near the main hallway door, but may vary). When hot tap water is needed the boiler is switched on and provides hot water within 15-20 minutes, typically. After use the boiler is again switched off. The really thrifty have learned to shut off the boiler before the last shower or then run the dishwasher to utilize the remaining boiler heat to advantage.

    The efficiency answer is an Indirect Water Heater, a super-insulated storage tank heated by your boiler and substituting for your Immersion Coil. The best of these are made of stainless steel, super-insulated to lose about 1/2 degree F per hour and have lifetime warrantees. Additionally your Boiler Aquastat Control (controlling boiler temperature) should be changed to a “Cold Start Aquastat”, allowing it to heat ONLY when area heating or Domestic Hot Water is demanded or used to maintain tank temperature. Your boiler is now an “on-demand” type, lowering toward room temperature between cycles.

    This storage of a quantity of heated tap water not only gives you instantly available hot water at any time but is inexhaustible, with your boiler cycling to meet any demand. No more initially hot water that cools down quickly with use caused by under-sized or sediment-clogging Immersion Coils either. Yes, the thrifty can still use the Emergency Switch trick for additional savings. In fact, one family of four with two young boys has found that they need only switch on every two days in the summer after several showers, dishwasher, wash the dog, etc.

    Your boiler runs less and runs cooler on average too, prolonging its life while reducing radiated and chimney drafted heat losses. Efficiency gains all around.

    Note: This argument also applies to separate Electric, Gas or Oil Hot Water Heaters by incorporating them into a managed, single fuel system.

    Last Edit: 10/10/2012 pdm