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Hot Water

Hot Water 101 Articles

  • Do I need to flush an old radiator from time to time?

    No. Hot water radiators operate within a “closed” system where there’s little or no corrosion taking place. Flushing these radiators will only cause you to add more water to the system, which will...

  • Where does the air vent belong on a hot water radiator?

    Each hot water radiator should have an air vent at the top, on the side opposite the inlet pipe. You’ll use this vent to “bleed” air from the radiator when you’re first starting...

  • Does a two-pipe steam radiator have to have a steam trap?

    No, but it has to have something to keep the steam from entering the condensate return lines. That “something” may be an internal orifice, a tiny check valve you can’t see, a hidden...

  • What’s the difference between a steam and a hot water radiator?

    It’s the way the radiator sections go together. They may be nippled together at both the top and bottom, or just at the bottom. Older steam radiators have nipples across just the bottom portion...

  • The best place to install a cast-iron radiator

    *Q: If I decide to move a cast-iron radiator, where should I reinstall it?* *A:* Ideally, a cast-iron radiator should be under the window (that’s where the greatest heat loss is), and it should...

  • What’s the best way to disconnect, move, and reconnect radiators for floor repairs?

    First, take care with those old pipes. Make sure you’re using two wrenches when you’re loosening the union connections. Assume the position, and then turn one wrench while holding back with the other....

  • Can I successfully cut down the size of an antique cast-iron radiator?

    Maybe. It all depends on how the long-gone manufacturer assembled the radiator. A cast-iron radiator goes together in sections, like a loaf of sliced bread. Each section attaches to the next with round...

  • PEX for Hydronic Distribution Piping

    PEX is a viable option for a variety of hydronic distribution-piping applications on both residential and commercial projects. With its durability, flexibility, range of sizes, system-performance characteristics and labor-saving benefits, PEX need no longer take a back seat to traditional metallic materials in the design and installation of a distribution piping system.

  • How to Remove an Old, Threaded Fitting Video

    A Wallie, *Bio*, posted this video as a part of a great thread that *Delta T*, another Wallie, started. He posted: Thought I would share this trick for getting an old threaded fitting...

  • Cast-Iron Radiator Restoration: Removing old pipe nipple to make way for new fittings Video

    Bob "Hot Rod" Rohr of Caleffi shows how to remove an old pipe nipple to make way for new fittings when restoring a radiator.

  • Threaded Copper Tubing

    *A discussion on The Wall: * *Paul S*. asked, "Has ever heard of screwed copper pipe? I have it on a job and sizes are way off. I guess it has the same OD as steel...

  • Dissimilar-metals and electrolysis corrosion

    *I asked this question on The Wall:* When do you think you need to protect against electrolysis corrosion from stray electrical current, and corrosion caused by dissimilar metals? In all cases, or just...

  • Dan Holohan's Classic Hydronics Seminar Video

      Here's an excerpt from Dan Holohan's Classic Hydronics seminar. *Click here to purchase this course.* In this all-technical three-hour-and-ten-minute seminar, Dan Holohan will give you a Liberal Arts education in those Classic Hydronics systems....

  • Tips on Radiant Heat and Wood Floors

    *The wider the boards, the greater the chance for trouble.* Stick with boards that are no wider than three inches. Wide wood can warp. *Use mechanical humidity control.* The relative humidity in a radiantly heated...

  • Air in a hot-water heating system

    Air is the enemy in a hydronic (hot-water) heating system. It blocks there flow to the radiators. It rattles around and annoys customers. It wastes fuel by making our systems less efficient (no...

  • Watch the tailpipe

    Start your car on a cold morning and walk around to the tailpipe. See that water dripping? That’s the way a high-efficiency, condensing boiler works. It removes so much of the heat from...

  • Grocery store radiant

    A great place to understand radiant heating (or to explain it to your customer) is your local grocery store. Stop first in the gadget aisle and pick up a thermometer. It will probably...

  • Why closely spaced tees?

    Primary-secondary piping systems call for the tees that go off to the secondary circuit to be close together, ideally not more than six inches apart. Think like water and you’ll see why this...

  • Discovering Water Hammer

    *Discovering that water hammer has moved into any hydronic system, be it steam or hot water is never fun, but finding the cause of it sure can be. Hey, you get to...

  • Radiator colors

    Ever wonder why so many of the old radiators you see are painted silver? Back in the day, they were mostly plain grey metal, but then the Spanish Influenza arrived during the winter...

  • Pumping Away Piping

    This is an excerpt from Dan Holohan’s book Pumping Away and other really cool piping options for hydronic systems. Since you've read this far, I figure you must be pretty open-minded. You may...

  • Old Radiator Ratings

    If you're replacing a steam boiler, there's only one right way to size that boiler, and that's to measure the radiators. If you're replacing a hot-water boiler, you'll do a heat-loss calculation on the...

  • Let's chat about compression tanks

    *That I can get excited about compression tanks probably means that I'd be a lousy lunch companion, right? I mean who wants to hear about solving problems with something that hangs from the...

  • What is a thermostatic radiator valve?

    A thermostatic radiator valve enables you to control the temperature of that specific radiator, thus giving you greater control of the temperature and comfort of that room or space.

  • How do you paint cast-iron baseboard radiators?

    When painting cast-iron baseboard radiators, use an oil-based enamel type of paint like Benjamin Moore Satin Impervo for the best result.

  • Does my boiler need chemicals?

    Here are some tips from contractors about cleaning new heating systems, using boiler chemicals, and water treatment.

  • Special Tees

    These days, I think the most special tees are the ones designed to make primary-secondary heating systems easier for you to install.

  • Converting from gravity to pumped flow Video

    Here's a full day's work compressed into a couple of minutes, courtesy of our friend John Cataneo's Dropcam. There's a lot to consider when moving a hot-water system from the early-20th Century into...

  • What is the safe pressure for a hot-water-heating system?

    A member of the Wall community asks this question: What is the "safe" operating pressure in PSI for a hot-water boiler heating system, and what is the "safe" range in terms of temperature for...

  • How many times can PEX freeze before bursting?

    A member of The Wall community asked this question and I thought the conversation that followed was interesting: *"How many times can PEX freeze before bursting? At what temp will it only take...

  • Fernox injection for hot water boilers Video

    Gerry Gill is brilliant when it comes to solving steam- and hot-water-heating problems. Learn more about him HERE. 

  • The O-S Fitting

    I was looking at a photograph of Crosley Field, a grand, Cincinnati, Ohio baseball stadium that burned to the ground in 1900. The men in the photo are wearing derbies and loading debris...

  • How They Rated Radiators

    So go look in a radiator catalog and you’ll see the EDR (that’s Equivalent Direct Radiation) ratings for all those different shapes and sizes. We take those numbers for granted nowadays, but believe...

  • What do to with boilers during the summer

    I read dead people. Not many people graduate from Harvard at the age of 20 but Theodore Minot (who, understandably, went by T.M.) Clark did. Mr. Clark was born in Boston in 1845,...

  • Banging Zone Valves

    Here's Johnny! It sounded like someone was coming through the front door with a fire axe. We were sound asleep and then it arrived, as it did night after night, all winter long. BANG!...

  • Thermostatic radiator valves

    What's wrong with this picture? See the remote thermostat sitting on top of the hot radiator? The folks in that office wondered why they couldn't seem to get comfortable. You can't make this stuff...

  • Steam vs. Hot Water

    It was a real battle in the early days of heating. There were steamfitters and then there were the hot water people. I have a wonderful old ad from Honeywell that goes...

  • Don't size a hot-water boiler by measuring the radiators

    They built our house in 1950 here on the Isle of Long and it used to have a radiant heating system. In 1970, the previous owner noticed wet spots on his kitchen floor,...

  • Don't size heating equipment with rules of thumb

    The World Headquarters of HeatingHelp.com, our humble company, used to be in a tiny store in beautiful downtown Bethpage, here on the Isle of Long. We then moved to another, larger, store, this...

  • The Brilliance of Bathroom Heating

    The bathroom is arguably the most important room in the house. It is the only place where you can really lock yourself away and get a little rest and relaxation. As a result,...

  • Black radiators

    The search for the unique is a never-ending quest, something that mutates and evolves every single moment. The thing is, as a concept, uniqueness is almost ineffable and unachievable, and so when you...

  • Cast-iron radiators – A cost-effective choice for your home?

    As I am writing this, snow is on the ground and cold is all about. It sounds like something from A Christmas Carol. One of the biggest costs for all of us...

  • Buying Bathroom Radiators – Three things to consider

    I do not care what brickbats impugning my masculinity that come my way, I’m going to state something right here and now: I wouldn’t leave bed in the morning if my bathroom hadn’t...

  • When a radiant-heating system goes wrong

    Marianne and I were at the 5 PM mass last Saturday. We like going to that mass because it allows us to be lazy in bed with newspapers and coffee on Sunday...

  • Radiant heat and wood floors

    More and more radiant systems going into existing homes as retrofit projects. On many of these jobs the tubing winds up getting attached to the underside of the wood floor. On other jobs,...

  • The first radiant heating jobs

    Each morning, when I sit at my desk, I give a moment’s thought to the broken copper pipes that are buried in the concrete slab just below my feet. The guy who...

  • Types of PEX pipe

    You have options when it comes to the tubing you bury or staple up on a radiant job. You may choose to go with a particular supplier and never question the type...

  • Oxygen-diffusion corrosion in radiant heating systems

    Whether you’re doing radiant floor heating or hydronic snowmelt jobs, it pays to give lots of thought to this oxygen-diffusion corrosion business. Since this is one of those areas where the marketing and...

  • Levittown radiant heating systems

    I grew up in Hicksville, Long Island (don't laugh!) and I spent a good part of Junior and Senior High School sharing a classroom with Billy Joel, and that is my single...

  • Understanding primary-secondary pumping

    Primary-secondary pumping has become pretty popular nowadays, especially with boiler manufacturers. They love it because it offers a simple way to protect their boilers against low-temperature return water and the resulting flue-gas condensation that...

  • Primary-Secondary systems sometimes overheat

    The guy had told his architect to have a corner of his basement dug out so that he could play half-court basketball with his two kids. The ceiling was 14 feet above the...

  • Why your boiler needs a low-water cutoff

    A friend of mine who happens to be a contractor went out to look at a hot water boiler that was causing its owner a problem a few years back. It seems...

  • Loop system hot-water heating Q&A

    *Q: What's loop hot water heating? * A: It's the simplest method of heating with hot water. Each zone consists of a single loop made up of the pipe and the radiators. The...

  • How can cavity-wall insulation help your home remain heated?

    Keeping your home heated is about more than just having a source of heating, as it also has a lot to do with preventing heat from escaping the interior of your house. This...

  • Insulate your home and get energy efficient

    The cost of heating and running our homes on electricity and gas continues to increase. With the amount of money being spent by millions of families every year, it’s important to make sure...

  • Bubble-foil insulation

    On this subject, I'll direct you to Robert Bean's HealthyHeating.com site, where he makes his case very well. 

  • Best insulation tips

    In the autumn, of the block of flats in which I live (I’m not posh enough to live in an apartment) I had cavity wall insulation installed. What followed a few months...

  • A heat-friendly house - simple tips to improve insulation

    Now that the price of heating a house has gone completely through the roof, homeowners have to be far better at saving energy than they used to be. Gone are the days...

  • Indoor Air Quality and Tight Houses

    Good IAQ starts with a tight building. It is often said a house has tobreathe. This brings to mind a Prohibition-era movie where one gang has captured members of their rival. Lined up...

  • Basics of Indoor Air Quality

    We of the Hydronic Realm often don't think too much about Indoor Air Quality, but that mindset is obsolete. We need to look at the Big Picture, not just the heating system. We...

  • Indirect hot-water heating Q&A

    *Q: What's "indirect" heating? * A: It's a method of heating the old-timers used to warm fresh air before it entered a building. *Q: How did they do this? * A: They placed the...

  • Honeywell Heat Generator

    My run-in with Mark Honeywell (and the day I met his Heat Generator) Mark Honeywell. Yeah, that one. The guy who has his name on all those thermostats. He, and Dave and I...

  • Orifices and gravity hot-water heat

    Gravity hot-water heating is both the simplest and the most complicated system ever to come driving down Hydronic Highway. It’s simple because it has so few moving parts. The water is the only...

  • Should fill valves be left open or closed?

    Now there’s a question for you. The feed valve’s job is to, well, feed. You figure out the height of the hydronic system from the point where the feed valve is to...

  • Diverter-Tee Q&A

    *Q: What's the principle of the diverter-tee system? * A: This system lets you supply hot water to a radiator and return cooler water from the same radiator by using a single pipe. one...

  • Converting from steam to hot water heat?

    First things first. Before the 1920s, most steam contractors used cast-iron, column-type radiators. Those are the free-standing ones with the real wide sections. Column radiators were perfect for steam heating because they had...

  • How to run a hot-water zone off a steam boiler

    *Q: Is it possible for me to use the condensate in a steam boiler to make a hot water zone? * A: Sure! Heating professionals have been doing this for years in areas...

  • Why compression tanks waterlog

    When hot water heating was new (and this goes back to the turn of the century) the Dead Men installed gravity systems because Homer Thrush had not yet invented the circulator. Up in...

  • Why some compression tanks fail

    Packaged boilers have been popular for a very long time and they sure do make a contractor’s life easier. These days, most packaged boilers come with a circulator in the carton, and not...

  • Some gravity-hot-water systems didn't have compression tanks

    It all started when a friend called to tell me about this old gravity hot-water system that had him baffled. “There’s no expansion tank anywhere on this job,” he said. “You sure? I asked.” “Yep....

  • Gas-Pipe Sizing Chart pdf

    Which is just that! 

  • Using vacuum gauges to tune an oil burner

    Vacuum Gauges Paint a Picture for You By painting a picture I simply mean that when you use this instrument it will reveal some much needed information when diagnosing a fuel related service...

  • Why Do I Need a Chimney Liner?

    There are several reasons why installing a stainless steel, flexible chimney liner is important. The primary reasons are to ensure the safety of your home and to maximize the efficiency of your heating...

  • Is Chimney Liner Insulation a Must?

    Here’s the quick run-down on insulating your chimney. Insulating your stainless steel chimney liner is highly recommended. Chimney liner insulation helps ensure safety and efficiency of the chimney. Insulation allows for the flue to...

  • Choosing the Right Chimney Liner for Your Application

    Your current chimney flue may be showing signs of deterioration, such as a hairline crack in the flue, missing mortar between the clay flue tiles, or you may not have a flue at...

  • Why you should never dead-head a circulator

    When I was still young and very wet behind the ears I worked for a manufacturers representative in New York City and we sold Bell & Gossett pumps to wholesalers. It was...

  • The Point of No Pressure Change

    In 1994, I wrote a book called, *Pumping Away[http://store.heatinghelp.com/pumping-away-p/104.htm]*, which I began by remembering the late, great Gil Carlson. Here's what I wrote: "When I knew Gil Carlson, he was never far from the cigarettes...

  • The Hidden Costs of Hidden Pumps

    If you're watching the news you probably realize that, these days, Americans are becoming more conscious of green things, as well as rising fuel prices. I think that's good – both for the...

  • Sizing circulators for old gravity-hot-water heating systems

    When servicing old hot-water heating systems that originally circulated by gravity, but now use circulating pumps, I began to notice a lot of oversized circulators. In some cases, the circulator was so severely...

  • Net Positive Suction Head

    NPSH also stands for Not Pumping So Hot I was lucky to have had as one of my teachers the late, great Gil Carlson. Gil was Bell & Gossett’s Director of Technical Services...

  • How to Size Circulators

    In 1970, I went to work for a manufacturers rep on the Isle of Long and I fell in love with hydronics. We sold Bell & Gossett and one of the elder...

  • Adjusting the flow rate for an old gravity-hot-water system

    A hot-water stumper About eight blocks from my house in Baltimore, there is a large two-family house with an equally large hot-water heating system that originally circulated by gravity. The original boiler, a Spencer...

  • Boiler Ratings Explained

    When you look in a boiler manufacturer's catalog you'll see that there are several types of ratings for each boiler. There's the Input rating, the Gross Output rating (which some call the D.O.E....

  • Why winter may mean that you need to get a replacement boiler

    Winter has crept up on us in the UK. The cold winds and downpours were inevitable, and now the snow has begun to sprinkle its flakes across the country. The change in temperature...

  • What is a Wood Boiler Heat Exchanger?

    Wood furnaces have many benefits and are installed both indoors and out. With a heat exchanger, the hot air is transferred throughout the home or business via a venting system constructed of copper...

  • Thermocouple Testing Procedure

    I am often asked about troubleshooting a thermocouple on gas systems. This will be a permanent reference that will give a step-by-step procedure: A thermocouple is a device used to satisfy pilot safety...

  • Modulating-condensing boilers

    A question asked on the Wall, "Who, in your opinion, makes the best modulating-condensing boiler?" *Andrew Hagen replies:* My favorites in order: 1. Viessmann Vitodens 2. Triangle Tube Prestige 3. Lochinvar Knight I...

  • How to have a boiler replaced

    "We haven't had decent heat since that heating contractor left our basement."  She was about as angry as any homeowner who had ever called me. "We paid good money for that new boiler,"...

  • Considerations when using constant circulation

    A question asked on the Wall, "What do I need to consider with a hot-water system running on constant circulation?" *Mark Eatherton replies: * It has to be designed into the system from the...

  • Boiler Failure after Two Years

    The boilers (and there were 20 of them) were laying out there in the parking lot, not far from the boiler room door. I could see them as Joe and I drove...

  • Heating in France

    I was in Paris one chilly November, where I had the wonderful opportunity to explain American-heating practices (such as they are) to the folks who run most of the huge European boiler companies....

  • Heating in Russia

    My buddy, Fred, was over for a visit and the talk turned to steam. Fred works for Consolidated Edison in New York City. Con Ed provides the electricity and steam for a...

  • Wood, Solar and Other European Lessons

    I first went to the big ISH fair in Frankfurt, Germany in 1991 with two buddies, and I think we three were joined by only about 17 other Americans that year. ISH...

  • A Different Way to Pipe

    I was raised by Bell & Gossett and gobbled up the writings of the late, great Gil Carlson for a lot of years. I learned about Monoflo systems and primary-secondary pumping, the importance...

  • Antifreeze for Hydronic Systems

    In response to a person on the Wall who asked, "Can I add antifreeze to my heating system?"   *Brad White replies:* Antifreeze is commonly done but like anything else, you have to do it...

  • Mixing passive and active heaters can lead to problems

    Sometimes, you just have to think like air. The house had been sitting on this old Connecticut street for more than 100 years. Children, grown and long gone, had once skipped across its...

  • Gravity Hot Water Heating Q&A

    *Q: How long has gravity hot water heating been around?* A: Gravity hot-water heating began quietly in the United States between 1875 and 1885. It was a Canadian import, a safe substitute...

  • Why Some Compression Tanks Fail

    Packaged boilers have been popular for a very long time and they sure do make a contractor’s life easier. These days, most packaged boilers come with a circulator in the carton, and not...

  • Lochinvar's SHIELD™ commercial water heater Video

    Here's an interesting new product from our friends at Lochinvar.

  • The first hot-water heating system Video

  • Wall-hung boilers (and all that comes with them)

    They sell a lot of boilers on the other side of the sea. Sixteen countries make up the European/Chinese boiler market. Here they are, high to low, in order of sales during 2006: United...