• Tag Archives Conversion
  • OIL TO GAS FHW HEATING CONVERSION — ALL OF YOUR OPTIONS

    With the “Fracking Effect” of plentiful, relatively inexpensive natural gas (and oil) upon us, there is a continuing heating system conversion trend from oil, and justifiable in degree. However, this rush borders as all rushes do on becoming foolhardy. In the New England Region our magic number has been a $45-48 per barrel crude oil price, but it’s at best a “crude” one (please excuse the pun). We have seen a significant gas vs. oil crossover now in the past three (2016, 2017 & 2018) heating seasons. (Ref. our Heating Blogs.) It’s an easy sale to “play the numbers”, telling the customer what they want to hear. The typical scenario is an immediate “boiler swap” with perhaps a less than ideal economic resultant. But there are alternatives, depending upon your particular circumstance.

    If you are fortunate to have immediate, metered access to natural gas and your existing oil-fired system is “old enough to vote”, the choice is obvious — swap it! However if you have a newer oil system and it performs well except for the fuel bill, you have other options. Similarly, if you live in a non-natural gas area and are using propane, your incentive differs very substantially.

    Let us review these potential scenarios.

    Firstly, we must qualify your natural gas source AND it’s actual, delivered cost to you! It is a “distributed” fuel, like electricity and therefore has multiple service charges assessed. Always get an actual billing estimate as with any distributed fuel.

    Please refer to our additional, related Blogs from our site library for more detail. We will hyperlink as we proceed, but not necessarily all of them.

    The Installed Cost Premium of a Gas vs. Oil System must be considered and factored into any scenario. Gas systems are at minimum a 20% premium in our experience AND their life expectancy can be half or less of a cast-iron boiler system! Our blog “HIGH MASS vs. LOW MASS BOILERS – The Arguments”should be required reading in this regard.

    Recommendation: If you do not have natural gas access currently in the building, solicit and qualify its installed cost before further consideration!

    1. If it’s on your street the line extension may (or may not) be free as an incentive by your provider.
    2. If it’s down the street a ways there likely is a significant service extension cost up front. There may also be group incentives to extend and supply a neighborhood. This cost must be amortized over some service period. “Run the numbers.”
    3. Natural Gas (like Electricity) is a Distributed Fuel. As you know on your Electric Bill, the Kilowatt-Hour cost is burdened with service and distribution charges. Natural Gas is the same. Always solicit an ESTIMATED TOTAL GAS BILL from your provider!

    Read our blog USING A ‘HEATING COST CALCULATOR’ — CAREFULLY!….. For more detail.

    NOTE: We harp on using a “Heating Cost Calculator” for any project. “Gotta know where you are before you know where you’re goin’.”

    Another suggested “read” is our blog: HEATING FUEL SELECTION – FROM AN ENGINEER’S PERSPECTIVE

    Natural Gas (and Propane) Boilers (FHW) and Furnaces (FHA) are available in very different flavors, technically and efficiency-wise. The EPA assigned AFUE (Annual Fuel Utilization Efficiency) Rating can vary from the minimum required value of 85% to over 97% on Weil-McLain Products as an example. AFUE Rating must be obviously considered when making any system decision.

    Scenario 1: Older Oil Boiler (15 years or more), NatGas available on site, longer planned occupancy/ownership. Justify and replace with the highest efficiency unit available (Oil or NatGas) and enjoy the benefits. Note the substantial fuel cost premium of LP (Liquid Propane) vs. Oil if this is your only option ….. see also further below.

    Scenario 2: Newer Oil Boiler (under 10 years?), otherwise same as Scenario 1. Consider upgrading with a Gun Burner alone. Yes, there are several manufacturers of very high efficiency Gas Conversion Gun Burners. Among them:

    1. Carlin Combustion Technology.
    2. Wayne Combustion Systems Several Options.
    3. Midco International Residential Series.
    4. Additional Domestic and Foreign Suppliers.

    However, you must make an objective judgment as to the viability of this conversion. As an example the Weil-McLain Gold Series Oil Boiler has been around since 1995, still available and produced in quantity. It is an older “two-pass” design, 85% efficiency, with tight heat exchanger passages. A good candidate as are similar competitors’ models.

    A Gas Conversion Gun will be higher in combustion efficiency (up to 95%+?). Combined with the oil boiler that is efficiency-limited by oil’s chemical composition should provide you with very respectable boiler performance. We have no means of estimating this, but certainly the Gas Gun Manufacturer should have some history as a marketing tool. Ask!

    To expand our point, we regularly scour Craigslist for Cast-Iron Weil-McLain Gold Series Oil FHW and Steam Boilers as budget upgrades in our area (NH). We can save several thousand dollars by obtaining a well cared for unit for sometimes just above scrap value. Haven’t bought a lemon yet!

    Read our Blog: BUYING A USED BOILER? – CAVEAT EMPTOR (BUYER BEWARE)!

    Scenario 3: What about a LP (Propane) Conversion? The Fuel Cost Premium in our view has relegated propane to a “fuel of choice”. As of this writing, Propane is a 42 to 91% premium over #2 Fuel Oil regionally, using 95% and 87% Appliance Efficiencies (AFUE) respectively as a comparative. Otherwise the outlines in the prior Scenarios apply.

    Subsequently propane is primarily used for cooking, drying and seasonal or supplemental heating along with a wood, pellet or coal system in our rural area. Propane heated properties are therefore slower and lower sellers.

    There is however some relief that may be available to the propane user. Gas tanks are typically owned by the fuel dealer, locking the customer into his supplier. Conversely, oil tanks that are owned by the customer provide sourcing negotiation flexibility. Our customers advise substantial fuel purchase savings via direct negotiation. “Fuel Club” membership is another very desirable purchasing option that we personally employ.

    Commercial and particularly industrial propane clients typically own their storage tanks and contract with suppliers. There is no reason not to own your own tank, save two reservations:

    1. The initial cost of the tank and its installation.
    2. The manufacturing date stamping of the tank, the subsequent re-testing and re-qualification requirements. Tanks are date stamped (Mo.-Yr.) and must be re-qualified ten (10-12?) years after manufacture. (If you buy a used tank, check the date stamp! Don’t buy a dying or at worst a dead horse.)

    We have a local tank-owner client who advised us of a recent propane buy at an astounding price! He shopped aggressively and paid C.O.D. His purchase price was well below that of the fuel oil equivalent at the time.

    So, you off-the-pipeline propane gas users may have some hopes yet. Check them out.

    In closing, propane has historically been a premium-costed fuel. Having said this, it is conceivable that we may see a variant of natural gas emerge as a pressurized or liquefied fuel to challenge propane in the future. Stay tuned …

    Update: Read our Blog entitled “Oil Again The Cheap Heat in NH — For The Smart Buyer”. It documents the lower cost of oil vs. all other heating fuels @ a $32 a barrel this past winter. The approximate “break even point” with Natural Gas is currently around $45-48 a barrel. Fluctuations of both fuels (and others) should be qualified with a Current Heating Fuel Price Comparator, as we have noted in our Blog.

    Also reference our Delta-T ECM Hydronic (FHW) Heating Appliance™, bridging the Gas vs. Oil Heating Argument by applying the latest hydronic technology.

    Author’s Note: Updated 01/11/2019 P.D.M., Sr.


  • CONVERTING A STEAM HEATING SYSTEM TO HOT WATER – THE WHYS AND HOWS

    Steam Heating Systems were the Cadillac of heating options for residential applications for about a century. Pricey, tending to be a bit fuel-thirsty (regardless of the fuel used), they were extremely simple, durable and provided a superbly comfortable heated environment. Economics have gradually forced steam heating into the commercial and industrial process realms alone. So where do you go with that residential steam system? It depends upon your goals.

    When do you stay with steam rather than change over to hot water or some other heating form?

    1. If you have a nice, period home that suits your needs excepting to lighten up on your wallet a bit, just upgrade the boiler to a modern, high efficiency unit. Older boilers typically are large, with open heating passages to suit both wood or coal fires that when upgraded to gas or oil result in very poor fuel efficiencies. Presuming the system piping and radiators are serviceable there is little incentive to change over the entire system. (Steam heating distribution is arguably more efficient than hot water!)
    2. Similarly, if you like those decorative radiators that warm your hands, food, dry clothes on, etc. and take up less footprint and wall space than hot water baseboard, think again.
    3. If you plan an addition or heated area extension and envision running steam piping everywhere to heat it, there is the little known and utilized steam boiler “bottom water” forced hot water heating option. Circulating the lower water below the steaming chamber (top of the boiler) provides extended heating system flexibility. Furthermore, forced hot water extends capability to attics, garages and additions with baseboard, Unit Heaters (fan forced radiators) and Air Handlers (a ducted FHA Furnace with an internal radiator that heats your hot air vs. using a gas or oil fuel source). You must however convert zero-pressure steam water into approx. 15PSI heating water for circulation to new radiation. A correct plate-to-plate heat exchanger is required and circulation both from the boiler and to radiation added. A separate water supply source and an expansion capability must be provided for the pressurized heating water circuit as well. Note: Remember to size your now “two-state energy” Steam/Hot Water Boiler accordingly.

    There is an interesting “middle ground” where you can convert your existing, newer steam boiler to hot water operation while keeping those aesthetic steam radiators. You must however replace all the old steam system piping in doing so. Steam radiators work well with hot water, but at moderately reduced heating (temperature) capacity. More importantly is the higher water volume content of steam radiators and how to supply them properly for even distribution.

    Referring to our separate blog on FHW Heating Loops, you can’t pipe cast iron steam radiators in series and get even heating! Even a split loop will not work but for a couple of radiators at best.  The only effective option is the mono-flow loop system, branched for each radiator. All will require increased piping and circulator capacity.

    Despite the challenges, converting steam radiation provides some attractive opportunities, heating-wise.

    1. You maintain your prior heated area aesthetics and functionality with few perceptible changes.
    2. You can now re-pipe and “zone” the prior area with multiple thermostats, even down to individual room level if you desire.
    3. Obviously you can add additional heated areas (zones) as well.

    Fully converting a steam boiler to hot water operation and then replacing or adding all heating distribution components is the last and most complete option. Scenarios:

    1. You have an excellent steam boiler with an economic incentive in mind. If you just wish to swap this unit out for your existing, inefficient or failed FHW Boiler as a one-for-one, be careful. Make certain that the conversion components and labor (as applicable) justify the changeover.
    2. Changing your existing, older steam boiler to FHW in our view is questionable. You are trading off operational efficiency against upgrade costs.
    3. Steam Boilers typically and Weil-McLain Steamers (our expertise) in particular have several advantages over their sister Hot Water Boilers. The front and rear sections are notably heavier and bulkier, containing more cast iron and water that can contribute to durability and theoretically capacity. Can’t speak for other manufacturers, but the Weils are heavier and tougher. Check their Specifications. Also if you are using a DHW Coil (immersion coil in the boiler to generate your domestic hot water), steam boiler coil(s) have nominally higher capacities and larger (Weil-McLain) boilers sometimes have two coils, or provisions for them for greater DHW capacity delivery. Check.

    A recent phenomenon is the Outside Wood Boiler. You know, that thing that sits beside a house that looks like a Metal Garden Shed with a Smoke Pipe sticking up out of it and a woodpile alongside. They are typically owned by rural folks that have a great wood supply and don’t mind tripping through the snow to keep themselves warm. These boilers are also “zero pressure” systems. They must be adapted to a pressurized FHW System through a Plate-to-Plate Heat Exchanger, utilizing circulators and controls. (You must maintain constant electric service to these systems or it can get exciting and cold, or both.)

    Coupling an Outside Wood Boiler to a Steam System is dubious at best. The only deliverables in this scenario are preheated boiler water that must be then fired and converted into steam by the central boiler, but which can also provide DHW through its internal coil (if equipped) or by an Indirect Water Heater (Insulated DHW Storage Tank) as an option. It just doesn’t make sense except to generate a lot of Domestic Hot Water. Therefore, in order to utilize the Outside Wood Boiler effectively you must do a complete steam boiler conversion (or a hot water boiler substitution) with the appropriate scenarios as previously detailed. There is no “easy road to glory” on this one.

    So procedural, to convert a steam boiler to forced hot water operation you must:

    1. De-plumb all iron and other piping right to the boiler. It must be “bare” as we say.
    2. Remove all of the electric components and associated wiring.
    3. Remove the Boiler Jacket (usually sheet metal) and place aside for reassembly.
    4. First, locate and substitute a 30 PSI (FHW) Pressure Relief Valve for the 15PSI (Steam) Valve. VERY IMPORTANT! Forget, and you’ll get wet — and surprised!
    5. Remove the Water Sight Glass, LWCO (Low Water Cut Off), Pressure Switch, etc. (Clean off the front of the boiler, in other words.) Dope and plug all affected boiler taps.
    6. Check Immersion Coil (DHW) Gasket(s) and Blanker Plates for leaks. Fix them.
    7. The smart guy plugs, fills the boiler and pressurizes it to 30 PSI (until the Relief Valve opens) and then checks for ANY LEAKS! Remember, steam boilers operate at about 0.5 to 5 PSI in use. You may have sectional leaking issues and not see them at that pressure. Sectional leaks between boiler castings are usually catastrophic. Stop and rethink your options. But, assuming it passes …..
    8. Find the manufacturer’s boiler piping diagram and locate the preferred aquastat front tapping and insert the appropriate “Spud Well” to receive the aquastat.
    9. Reassemble the boiler jacket and provide the opening for the Aquastat “Spud Well”.
    10. From the Manufacturer’s Hot Water Boiler Manual, identify the control components and hardware necessary to refit. Present this info to your Qualified Heating Engineer or Technician.

    Pay particular attention that your Master Aquastat selection compliments your application. There are several operational options available and should be qualified prior to final selection. Our preferred is the Hydrolevel “Fuel Smart” 3250-Plus Aquastatwith “Electro-Well” for all conversions.

    You now have a tight boiler ready to reconfigure for your application. Your further risk is minimal, save a hot operation leak(s) that may or may not be seal-able. Now consult and utilize a knowledgeable source.

    Be mindful that in converting any steam system to forced hot water you reduce the capacity of that system by 10% or more, if that is a consideration. Steam operates at a significantly higher system temperature in its vapor state than can be safely achieved with heating water safely below its boiling point.

    It may be implied from the above that we discourage steam to hot water boiler conversions. We have done it very successfully, once with an almost new Weil-McLain Gold Steamer and we’ve never been back. Do your homework!

    The option of acquiring a near-new FHW boiler instead of converting your steamer, particularly with the preponderance of on-going fuel conversions can also make very good sense.

    Hope this has helped you assess your particular situation.

    Updated: 11/28/2018 pdm