• Tag Archives Radiators
  • WHAT SIZE BOILER DO I NEED? – MEASURE YOUR RADIATION

    If you have read our other blogs you will note that we are advocates of using a Heat Loss Calculator to determine your heating system boiler size and radiation requirements. However, when replacing an existing boiler in a hydronic (forced hot water) system a shortcut method is available, subject to some qualifications.

    Measuring your total radiation (baseboard registers, radiators, cabinet convectors, unit heaters, radiant, etc.) can provide a good estimate of boiler size requirement. Simply put, installing a boiler that is larger than your radiation capacity is foolhardy. Excessive energy delivery cannot be utilized.

    Common residential baseboard is typically rated at between 550 to 700 BTU’s per linear foot, and typically at a water delivery temperature of 180°F by the manufacturer(s). These values vary with the construction, by manufacturer and somewhat by register height. A “rough measure”:

    1. 7-1/2” or under height = 600+/- BTU/Ft. (Variation +/- 50BTU)
    2. Taller than 7-1/2” is likely 700+/- BTU/Ft.(Variation +50BTU)
    3. Cast Iron Residential Baseboard is usually around 600BTU/Ft.

    Notes:
    1. There is no substitute for identifying your specific manufacturer’s product and specification, if possible.
    2. The “dirty little secret” however is that most of the baseboard radiation produced (particularly in New England) is by one regional supplier, and branded for boiler manufacturers to their specification. Thus the subtle aesthetic variations in sheet metal profiles.

    Given the prior, merely measuring the nominal length of your “fin tube”, adding them up to obtain a total radiation length and multiplying by your estimated BTU/Ft. selection gives you a total radiation BTU capacity, and hence your boiler output requirement.

    This covers the prevalent usage of baseboard radiation as a FHW heat transfer medium, but what about the others? They must be addressed separately as follows:

    1. Cabinet Convectors: These are usually readily identifiable and many have their output specifications on a product label (external or internal).
    2. Unit Heaters: Typically found in basements, garage or work areas for incremental use. They have an external chassis specification label with rated values.
    3. Radiators (typically converted from prior steam usage, but not always): The number of original suppliers and variations of these is daunting. There are online resources citing dated cataloging that is useful, but you have to dig!
    4. Radiant Radiation (In or under-floor tubing) calculation is more challenging. You must know the actual length and size of tubing utilized by whatever means or design records available.

    There are other considerations to both qualify and quantify once you have your total BTU requirement calculation.

    1. When replacing a dated boiler (in a dated system) you must qualify what has been done to the heated structure in the interim. Particularly any energy requirement changes effected by millwork (door & window) and insulation improvements must be considered.
    2. Have energy improvements changed the heating “proportions” of radiation requirements, exhibited by uneven room heating? If so, add radiation to extremely affected areas where overall balance cannot be achieved by adjusting dampers on all radiation.
    3. There is a benefit to be gained by having excessive radiation effected by energy improvements. Specifically, temperature change requirements can be readily achieved, permitting thermostatically controlled, energy-saving setbacks.
    4. Similarly, the equipment duty cycle and mean boiler temperature reductions add up to measurable operating cost reductions.

    Regarding Items 3 & 4, we offer two “new system” observations:

    1. Some new homes are designed so radiation-marginal that functional thermostat setbacks are minimal, if at all achievable under deep cold conditions.
    2. Full house “under-floor” and “in-concrete” tubing radiation systems offer virtually no significant temperature set-back capabilities, a notable energy penalty!

    Summarizing, weigh the operating characteristics of your particular hydronic system application before selecting any boiler. Over-sizing beyond your radiation capacity is a waste of money. Given that:

    1. There is still no substitute for a well executed Heat Loss Calculation
    2. Look at an intelligent FHW distribution option such as the “Delta-T” System. A great system improvement that returns great benefits! (Read our other Blogs.)

    As another resource, Weil-McLain has a new “Boiler Replacement Guide” (Linked) that we highly recommend.

    “Times are a-changing” as they say, and quickly. Don’t miss the bus!


  • 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


  • WHAT TO DO WITH THE OLD STEAM HEATING SYSTEM? RUNS WELL, BUT THIRSTY!

    In the 1800’s steam was king! It ran the trains, industries, ships, heated the largest buildings and the finest homes. Steam heating continued in this respect into the early 1900’s to even smaller homes, providing distinctive styling and comfort to the American Lifestyle.

    Those beautiful Victorians, updated Colonials, Southern Manors, Seaside Mansions and latter day Bungalows were all heated by steam as the method of choice. They featured ornate radiation and huge central boilers fired by coal, cotton waste, corncobs, peat moss or wood — and lots of it!

    The age of cheap energy has passed and so seemingly the Age of Steam Heating ….. but not so fast! There is an old adage of “throwing the baby out with the bath water”, cautioning us to not dispose of the good to rid us of the bad. This aptly applies to steam heating in our opinion.

    The simplicity and comfort level of steam heating is unarguable. Those well placed, aesthetic and space efficient radiators emit both heat with a light hiss of escaping steam simultaneously heating AND humidifying our air. Room temperature can be reduced somewhat without a comfort penalty. To duplicate this environment requires mechanical creation using power humidifiers or more complicated HVAC Systems. (That’s also why common homes had a tub of water on the heating stove.)

    Three usage factors affect steam heating:

    1. Fuel efficiency. Those old steamers have heat exchanger passages and flue pipes intended for large, continuous combustion, low temperature fires that are the polar opposites of small passage, high temperature oil or gas fired systems.
    2. Installation or repair cost. Residential steamfitting is one of those fading (and therefore expensive) arts, it seems.
    3. Flexibility. Those big iron pipes don’t stretch or move readily. Extending a system seems formidable.

    Not so fast, again!

    You may have noticed that virtually nothing ever happens to the radiators and piping in your system — the distribution side of things. Yes, a radiator vent may stick so it can’t be adjusted. So you unscrew it (with the steam turned down) and replace it. A valve stem leaks, so you tighten or pack it. Unlike hydronic systems, no gurgling, noisy, tinny registers, circulators, relays or vents to go bad. Steam provides the absolute in physical non-mechanical distribution simplicity, efficiency and durability. This is the “baby” in our analogy.

    The “bath water” is that beast of a boiler — the dinosaur. This is where virtually all of the efficiency gains are to be had (plus a little smart usage). Additionally, this is where the third factor (flexibility) must be introduced and discussed in common.

    A steam boiler is like putting a partially-filled pot of water on the stove with a perforated cover over it to let steam escape in a controlled manner. When you turn on the stove the water rose in temperature until it generated steam. If you don’t need steam the water in the pot is still hot in degree and usable heat. There are therefore two usable components in a steam boiler — hot water and steam. As in past steam systems you can employ the hot water component to provide domestic hot water and additional forced hot water zone heating. So if you want to stretch your steam system to heat the garage or that added room, it’s available.

    That big iron hulk down there was designed with complimentary, rather large distribution piping. Hopefully at some point or through your efforts heat loss of the building has been improved. You don’t need the distribution size as a result. This is not necessarily a detriment, however. What is more important is to not under size the replacement boiler and it’s steaming time.

    As you create steam in a boiler, the boiler water level is reduced as steam rises throughout the distribution (pipes & radiators). Steam is condensed in the radiators giving heat, and this condensate (now as hot water) cools, slowly trickling back to the boiler. If you generate a lot of steam rapidly from a too small boiler, the water level drops quickly. The low water indicator feeds a quantity of new water into the boiler by design. Then the eventual returning surge of condensate “floods” the boiler, reducing or limiting its ability to create steam (heat). Make-up water management can be important.

    Worse, in the smaller boiler scenario there is also the danger of overheating the boiler to the extent that thermal shocking can be induced by replacement water, damaging the boiler.

    There are tricks to reduce these scenarios, but there is one guideline that works every time:

    Boiler Weight (Size) and Water Capacity = Performance Efficiency with Longer Boiler Life (Just look at the unit you are replacing.)

    We invite you therefore to compare the weights and capacities of Weil-McLain Steam Boilers with all of its competitors.

    If you are still determined to be rid of the old steam system in entirety, so be it. But save back those radiators. Don’t give your installer an extra payday.