Joined on June 30, 2004
Last Post on December 9, 2007
@ September 12, 2004 6:28 PM in Steam vs. Hot waterthe burner on-time was timed at between 5 and 10 minutes of combustion before the pressure in the boiler got off the mark. The main vented of non-condensibles rapidly. I had nice Gorton high capacity vents. As you stated, the mains vented in a minute or two, but the rollback kept the boiler going. Sort of like Sysyphus and the stone up the hill. :^)> The comment of burner on to steam at radiators was about 15 minutes on average. Before I insulated the mains in the basement, this was about 35-40 minutes! When they abated the insulation they took everything. I had a supply of one-inch sized for 2-inch pipe (should have been two, I know) but it was free. Still, cut the delivery time easily in half. When cycling, I had a 2 psi cut-out and 3 psi cut-in. I did not think to crank it down as is current wisdom. But it would cycle on a cold day (20's) about 4 times an hour, on for five minutes, off for 10 when the place was insulated. The boiler was a Burnham Series 4 if memory serves, installed in 1974 or so and retrofitted with EI and vent damper in 1978 when I bought the place. I sold the property in 1985 or so, and have no idea what the current status is. But I left it better than I found it!
@ September 12, 2004 4:15 PM in Steam vs. Hot waterWhat city and state do you live in? It would seem that your costs are average for a 0 F degree winter design area for the structure you state. (Here in eastern MA, I use about 900 to 1,000 therms a year in my 130 year old insulated house. At $1.40 a therm that works out to a little less than $1/SF, about what your house is doing. But this includes dryer, gas log, domestic hot water off the boiler and cooking. For your larger house, I would expect you to have a heat loss (uninsulated and at 0 degrees F outside with 68F inside) of about 50 to 55 Btu's per square foot at design. This is just empirical for discussion purposes. So your total heat loss would be maybe 200-220,000 Btu's per hour at design. Let's say 210,000 average. And let's stipulate that you are in an area that has 6,000 heating degree-days. I could see you using 4100 therms of gas per year and that you have a good price too. Until I know your rate and locale, I would assume you live in a more temperate area than I described. Remember if you convert to hot water from steam, you will lose significant capacity of your radiators as has been pointed out. Each square foot of radiator surface with steam, emits 240 Btu's per hour to a 70F room. If you go to 180 degree HW, this drops by over a third to 150 per square foot. If we assume that the building meets temperature now with steam, then simply stated all of your envelope improvements must offset the radiation diminished output. If you cannot meet the heat loss difference or add radiators to compensate, then stick with steam as Steamhead has suggested. A key thing to keep in mind (as may have been pointed out) is that the new steam boiler must be sized for the connected radiation, not the "new, improved" lower heat loss. Steam can be made to work beautifully and enhanced in all sorts of ways (Thermostatic vent valves on radiators, well-insulated mains, fine-grade pressure (vaporstat) controls all of which are detailed and referenced on this site. You ask which will use less gas to operate? I would say hot water, but that presumes that you are not factoring in the cost to convert radiators, just comparing apples to apples. I had rental property with both (3-decker here in Boston), steam on the bottom floor and hot water on the upper two. Even with the roof losses, (whole building was insulated) the cost premium for the steam, with well-insulated pipes and very low pressure, was about 20% higher than hot water heat. This is my experience. From T-stat "on" to steam at the radiators took about 10-15 minutes from a cold start and about 5 minutes with the hot water. Granted the hot water was warm then went to hot, but in the meantime the steam system was warming the chimney and outdoors giving up nada to the space to be heated.
@ September 12, 2004 3:49 PM in Steam vs. Hot waterbut I do not have to change the state of the fluid from liquid to gas to get useful (read: delivered) heat from it. On a per-pound basis, you are correct, no question. And by volume (1700 to 1 roughly) steam wins. Me? I just merrily circulate the coolest water that I can, enjoy the heat and not change the state of anything except natural gas and air into carbon dioxide and water vapor... But remember, I do love steam. Use it all the time in my work (and run out of it from time to time):^)>
@ September 11, 2004 12:06 PM in Steam vs. Hot waterThis is supposed to be a simple answer for the benefit of a general question as to which is more efficient. I am not ingoring the laws of thermodynamics. Ultimately nothing is lost, we both know that in a theroetical and absolute sense. (I measure my temperatures from a base level of room temperature not absolute zero. Kelvin scale may techically be more correct for absolute terms, but I do not keep my house that cold :^)>) The inefficiency of which I speak is relative to the heat delivered to the space served versus the fuel consumed in the process. Sure the heat generated by burning fuel all goes to atmosphere ultimately, but I want it to linger by my couch for a spell first, as much as possible. Factually, while my hypothetical steam system is coming to a boil, I can be delivering hot water to my space at much lower temperatures with my hypothetical and comparative hot water system. I can modulate those temperatures without affecting a change in state within the fluid. This is physics, not religion.
@ September 11, 2004 11:23 AM in push nipples or o ringssomething about compatible materials seeking harmony and unity in the universe we call a boiler, grasshoppa. After years of happy firing, the push nipples may become One with the Universe. (Just a bit of Budherus Philosophy, -sorry!) But point is, you may never get them apart. That is the downside. Rubber and its derivatives (EPDM, Nitrile etc). just seem so "temporary" in geologic terms, and the anti-freeze (anti-sleaze- is that a Freudian Slip, Mark?) issue is always in the back of my mind. Besides, you cannot call a gasket a nipple and what fun is that?
@ September 11, 2004 11:15 AM in Steam vs. Hot waterthat is but one point in a series of conditions. There are many as you pointed out others. I wanted to keep it simple and to the largest single physical difference, the change of state factor. The physics comment is just that, a physical fact that it takes energy to effect a change in state of a material (fluid- liquid water in this case to a gas, -steam). While this is occuring in a comparitive steam system, I can use the water beneficially in my distribution. I did acknowledge that you get that heat back, but there is inefficiency in the process. I'd rather put my Btu's in the house, not up the chimney waiting for steam to form. Your point about additional radiation losses from hotter surfaces is well taken (assuming that they are not in spaces where heat is not intended to go anywhere. Even if in a heated space, it is uncontrolled.) I think we agree, not sure any of your comments point to disagreement, am I right? I mean, I was comparing garden-variety steam to garden-variety hot water, even at higher temperatures approaching 212. The condensing boiler comment you made just adds to the contrast.
@ September 11, 2004 9:33 AM in what are these square-head valves?I like Tour and Andersson or equivalent Armstrong or Oventropp balancing valves. These have built-in T&P ports and have 4 turns open to closed (1440 degrees of turning) in the smaller sizes most of us use, and 8 turns on larger sizes. Compare this to a ball valve which has 90 degrees, and only the last 45 degrees or so does the work. The T&A type valves are a little more money, but well spent, especially on low flow systems where water flow management is critical. I for one do not have that fine a touch using a ball valve to balance. With the T&A valves, I become Goldilocks, and this one is Just Right...
@ September 11, 2004 9:27 AM in Steam vs. Hot waterThanks for welcoming me back, by the way, a few months ago. My attendance has been sporadic. I agree with your subtext premise that an efficient steam system will beat an inefficient hot water system every time. I was responding to the basic premise of comparison, one fluid to another, with all other things being equal. I kept it basic (perhaps too much so).
@ September 11, 2004 9:23 AM in Steam vs. Hot waterbut the basic physics remain that a pound of water heated from 68 to 212 but not vaporized has 144 Btu's potential. In a steam system, it will sit in the boiler and give only the boiler a warm, fuzzy feeling. You have to add 960-970 or so additional Btu's to get that stuff to move. Sure, you get it back upon condensing, but in the meantime, I can take that pound of water in a hot water system and put it to work while I am waiting for steam to form. Just the facts. And I can heat that water to any temperature I like depending on demand. Don't get me wrong, I love steam, understand it, and learned from Dead Men before I heard the term. (God Bless Ray Stevens). Steam is great, can be tamed, tuned and tickled to perform exceptionally well. But I like to play with the temperature of my fluids without resorting to drawing 20 inches mercury vacuum in my heating system. :^)>
@ September 10, 2004 4:17 PM in Steam vs. Hot waterin general because you can modulate the temperature of the hot water relative to outdoor temperature as one reference. Steam by definition at sea level must be 212 degrees F. PLUS the heat of evaporation which turns water at the boiling point actually in to steam. Steam moves without a pump so that is one economy.
@ September 10, 2004 9:22 AM in Viessmann Vitodens experts near Rhode IslandViessmann in Warwick. Stephen David is my favorite contact there and he may be able to direct you.
@ September 10, 2004 9:07 AM in Chilled water coolingI have no idea what I was thinking- You are absolutely correct. I had it in my head at a btu for btu...therms per ton...96,000 BTU's for 60,000 BTU's. My bad. That should have jumped out at me. Time for vacation. The 46 ton house is a shingle-style, about 20,000 net SF with lots of south facing glass and ventilation load, in Massachusetts. Two (2) Viessmann Vertomats (one standby) for all heat, the pool(s) and domestic hot water.
@ September 8, 2004 4:48 PM in Chilled water coolingon the five ton and up scenario. Issue is cost but you cannot beat the flexibility. Multiple zones on one cooling machine. Keep in mind system volume and use a 3-5 minute flow rate volume tank on the return side so the chiller does not cycle on and off at part load. I have a problem with Servel type gas fired absorbers. They take about 96,000 btus of gas to produce 5 tons (60,000 btu's) cooling. At the cost of gas ($1.25-1.40 a therm?) that is $5.00 to $7.00 an hour, sort of like having your chiller earn minimum wage (absent a favorable summer rate). If electrical and 1.2 kW/ton and 12 cents per kW, that is 72 cents an hour for the five tons, unless I am missing something. Personally, I like TSI Chillers, out of Pryor, Oklahoma. Good equipment, stock parts available anywhere, and custom flexble. I have used them in the 3 to 8 ton range and in fact designed a 46 ton chiller for a house (some house!) several years ago.
@ September 8, 2004 4:40 PM in Does an interior chimney need to be lined?I do not have the input handy but the manufacturer would have data on a recommended flue diameter and height. If to be lined, my first choice is stainless (good corrosion resistance balanced with cost). AL-29 4C is nice if you can afford it. If you go refractory, I do like the Perma-Flue system but it is not necessarily allowed in all jurisdictions. It is allowed here in MA but only for retrofit situations.
@ September 8, 2004 1:08 PM in HB Smith G300I was going to call you and ask this one of you. Speedy...
@ September 8, 2004 1:03 PM in Does an interior chimney need to be lined?into the chimney? (Not speaking to the code aspects especially in Nassau County). Technically and in my experience, I have vented an atmospheric-fired appliance into an interior unlined chimney for years without a problem. (I since went to a direct-vent Monitor MZ so the chimney is now dormant.) However, IF you are going to vent a high efficiency appliance (condensing boiler or something in the range of 86% or better in some cases) manufacturers warn against it. Also if it is positive draft (forced outward) and the chimney leaks or has restrictions, the gasses may go through the brick and openings into your living space.
@ September 8, 2004 12:57 PM in air purge valves for baseboard hot waterThere, I feel better now. If the relief valve is weeping, check your system pressure, expansion tank or not. If all small piping as I think you said, a size 30 tank would accomodate a lot of that. If parts are an older gravity system (doubtful but for comparison) do a volume take-off and size it correctly. Now- the make-up valve. Is it too weeping by? Or do you even have one? Let's eliminate that relief valve issue first and go on to purging. You can use baseboard tees at high points, or automatic vent valves, sure. What is more common is a purge valve set-up at your boiler. Just a ball valve on the return prececed by a tee and hose-end drain valve. Pipe up a hose with make-up water on the supply side, close all valves to other zones including the one you are purging, and run a hose from the purge drain cock to a sink or outside. Let her rip. After a few minutes, when the stream runs clear with no "air embolisms", that is a good place to start. Purge your circuits one by one. Treat yourself to a SpiroVent if you can, upstream of your main circulator. That will remove the air released by the heating process over time. Once heated, run each circuit one at a time throgh the SpiroVent to release each circuits' initial heat-released air. After that, the SpiroVent "polishes" the water of air over time.
@ September 8, 2004 10:34 AM in Boiler Overfills Reason Unknownin the heating season when, I agree, some condensate would hang up then be released such as by a vacuum breaker. Because the over-fill occurred in the summer when the system was said to be down, the only source(s) of water connected to the boiler are the domestic water coil and the manual make-up water valves, JMHO. With the coil now said to be disconnected, that leaves those darn valves. As an experiment, disconnect both. If water still appears, call the Pope and then set up facilities for the pilgrims sure to appear at the Shrine of St. Peerless of Eternal Water. Dominus Vobiscum
@ September 8, 2004 8:43 AM in Boiler Overfills Reason Unknowndisconnected from the water source? A pinhole leak can add quite a bit to the boiler. I agree it is unlikely that two ball valve in series would both leak. However, depending on how much water is captured between the two ball valves, there may be another issue. If water is captured betwen them and that section is full, Boyle's Law governs and may allow weep-by due to infinite pressure of a contained liquid. Not terribly likely but easy to eliminate as a factor: 1) Shut the farthest valve from the boiler first, (boiler off) and wait a moment. Then shut the second valve, with presumption that the intermediate pipe has drained. or 2) Provide a tee and drain-off between the two. This is what is known as a "double-block and bleed" to prevent said problem. Still, my money is on a connected but dormant domestic coil with a leak.
@ September 8, 2004 8:33 AM in where can i find design temp, max snow level?is the root of most of ASHRAE numbers. I forget the link but I think it is off of the NOAA web site. As a design engineer it is worth the $75 for the CD for a world of data. Really, the world. When the USAF has to deploy forces and establish bases, they need to know projected fuel consumption demand, snow, wind, cooling, heating degree days, humididy, everything. If you could e-mail me with your most specific location, I can send you a copy of the data. It is in handy .pdf format, in color and is 18 pages per location. Lots of graphs. Fun in an engineer sort of way :^)>
@ September 7, 2004 2:55 PM in Boiler oversize problemSounds too low in BHP for modulating fire but do you have or can you at least get lo-hi-lo control on the burner? Again, as Kevin suggests, only with manufacturer's blessing. What is the cut-in/cut-out differential? Can the system tolerate wider swings?
@ September 7, 2004 2:49 PM in airlines questionPriority Mail. The $3.10 you spend will be easier than taking off your boots and bending over for a TSA rubber glove exam. Thermostats have no terrorist value. When al Qaeda tried to use them in Afganistan, the temperatures soared to the 110's in the shade so they abandoned that program. :^)>