Heating Help

I would take

@ June 20, 2008 5:30 PM in brass manifolds approved for use with potable water?

Uponor at their word. If they say "no", why would the plumber contradict that? Red flag for me. It does go state by state, but here in Massachusetts all components have to be approved by the plumbing board. One of the things they look for in particular is the lead content of the metal.

Glad to know

@ June 20, 2008 5:27 PM in unlined extrol expansion tank installed with potable water

you are planning on getting that tank out of there come September 14th- must be your birthday? :) Just a typo, I know... :) The unlined expansion tank issues have to do with the interior coatings in the tank and their dissolution in potable water over time. The potable water tanks you want have a National Sanitation Foundation label (NSF-61) which you probably know. The hazards are chemical as far as I know, not biological (although I always did wonder about stagnant water in the tank itself so that is something I do not know.) The stagnant water issue would be common to any tank I would think, so enough about that. I would say that a flushing and chemical disinfecting be done per code. (I specify it regardless after any work is done which violates the water system such as soldering or if it has laid fallow and open for any length of time.) Your plumber should be able to guide you and others are in a better position to advise than I.

Phase Change

@ June 15, 2008 5:26 PM in Got a question

is a kind of surgery we do here in Massachusetts by the way. Everywhere else it goes like this: Change of State of ice to water or water to ice is 144 BTU's per pound. Here is some trivia behind it: Take one ton of ice, (2000 lbs.) and melt it over a 24 hour period. If each pound absorbs 144 BTU's, the total amount of heat to be absorbed is (2,000 x 144) or 288,000 BTUH. If over a 24-hour period, that 288,000/24 = 12,000 BTU's per hour. That is the origin (and definition) of "one ton of cooling", all based on the rate of a ton of ice melting over a 24 hour day expressed on an hourly basis. To change water to steam (at sea level atmospheric pressure of 14.696 PSIA from and at 212 degrees F.) takes 970.3 BTU's as Devan said.

I really have to admire

@ June 15, 2008 5:12 PM in Bromo Seltzer (Arts) Tower Trap Rebuild and TRV Install

a company that makes it's own tools (stamped with your name no less, probably so they will not walk too far :) Seems the Bromo Building really has your number now, probably works better than it did on Day One and will see years of good service. I hope that puts your name more indelibly on the map! Oh, Photo #5? Classic textbook shot of either: 1) Testing for Temperature the Old Fashioned Way or 2) Little Dutch Boy Find Leak :)

Paul has it

@ June 14, 2008 5:34 PM in early barometrics?

Exactly, a wind venturi. The weathervane tail directs it to the strongest wind. Think of it more as a draft inducer than a barometric function. I have seen them used most predominantly as ventilators, not as combustion inducers.

What?

@ June 14, 2008 11:14 AM in Insulation

There are NO dumb questions, LoriMae. Get that out of your head. If you are planning to do an open blow in the attic floor, renting a blower is fine. Buy good material, the best you can afford. It should have the appropriate UL labels. A recognized brand such as NuWool, Greenfiber Cocoon among others. No "Brand X" or off-label products. If truly an open blow (no floor boards or walking surfaces) be generous with the material. If blown between joists but below boards, strive for maximum density. Before you do this though, you have a blank slate! Time to go over the plumbing, wiring and other open chases in detail (IN DETAIL) with canned foam. Be bold and seal those gaps. You will not likely ever do this again so do it once. (Last summer I removed R-75 of old insulation due to raccoons using my attic as a cheap hotel. NOT fun, but once stripped out and cleaned, the opportunity to seal the attic floor was presented. I got a second chance, you will likely not.) If you DO opt for a professional installation, seek a "Dense-Pack" application. If they insulate the rafters, a non-woven mesh is stapled across the rafters and the material is blown to a decent density, definitely not a DIY project. I have seen this done with a wet-spray (damp spray really) on a new house in RI. I did a blower door test and even unfinished (without window trim) it tested out to 0.10 Air Changes per Hour (ACH). It was so tight it needs a heat recovery ventilator, but that is a nice problem to have.

I had asked this

@ June 14, 2008 11:05 AM in Refrigeration pipe sizing

about six months ago and came up empty on R410A. What I have seen in the field at least is that the sizes, even over good distances, seem a tad small from what my gut says would be ideal. They seem to be "connection size" if not, then "connection size plus one". Still, the systems work but I am specifically NOT giving this as sizing advice. It is just what I have seen and is hardly the last word. Far from it! The manufacturers I have spoken with (Mitsubishi and Daiken being but two and regarding their VRF type systems), have given me blank looks but then point to their sizing and design software showing, routinely, 130 foot runs of 3/8" liquid and 1/2" or 5/8" suction lines for a ton or so worth of evaporator. For 134A, I have that in my tables and sizing program. If you have a specific application, fitting count and lengths, I can spot you a sizing run if you like. But 410A? I would love to have a good set of charts...

So this is what

@ June 8, 2008 2:04 PM in Single pipe steam, house insulation

is keeping you up at night... :) You are correct in "the right way" to go about your project- minimize heat loss, correct the radiator sizing and size boiler accordingly. Few actually do the second step but bravo if you do. Absent doing the second, you have to skip the third and size based on connected radiation as you know. I would not change the piping to reduced radiators. No harm in that and chances are you would not reduce the radiator to a point that the connecting piping would make a difference. I mean, if you have a 1-1/4" pipe and you can get away with a 1", why? Leave it. Lower pressure required at an academic level. That said, uninsulated piping of any size will exacerbate any pinging or banging or short cycling you may already have. Stripping piping will create it. Insulate all piping regardless of size- that is where the benefit lies. The difference in heat loss between one size of pipe and one size smaller, especially if both are insulated, is too small to go to the trouble of thinking about it, let alone to change it.

All Good Advice

@ June 8, 2008 1:53 PM in Dental Office heat gain

All of the responses have the right nuggets. To add my $0.02 at risk of repeating or re-stating: I have designed a good number of medical facilities (but fewer dental facilities but still some valid experience). The last one, a few years ago, had about a dozen operatories and a full floor fit-out of a very large practice as an example. I have found much of the "load foraging" and zoning are the most crucial parts. In other words, if the sterilization core and back-of-house prep rooms are joined with exterior patient operatories then someone will be unhappy. One would hope that the former would be grouped on a dedicated zone. It is these loads which contribute a very strong "base" load and that does not need to be coupled to fluctuating exterior zones. The operatories have fairly steady internal gains, the largest variable being the exam light (with a high radiant component). That is mostly directed at the patient but the convective components do go to the space in general. I typically take those lamps at 75% diversity. They are on for about 20-25% of a given workday but the lingering off-heat goes on for a while. Regular lighting I take at 100% diversity. Nowadays they usually have that DVD video reel going, showing before and after shots of cosmetic dentistry. Some have plasma screens, a high radiant output to be sure. Specifically, make your own inventory of what is in the room, what is "on" and for how long. I usually count three people per operatory, sometimes four if dental surgery. If the dental hygienist is 19 and perky, add another 250 BTUH. :) The other part about operatories is latent load. Folks are gowned up today per current health protocols so keeping Dr. DeSoto from sweating up under his goggles is a mitzvah. Size sparingly for maximum dehumidification or better yet incorporate a dehumidification mode which over-rides temperature. Other than calculated internal gains, your exterior gains are taken as per a normal building. Note well though that most operatories use blinds for privacy so the sensible solar heat gain factors increase somewhat due to the hot buffer space created. A good program will sort this out. Document everything, double check, then rinse and spit. See the receptionist for a follow-up and floss daily. Brad

Another thought

@ June 8, 2008 10:24 AM in Condensate inside A/C ducts

Reflecting upon what Chris was saying, plus I had time to access some of my tables and resources.. :) Naturally we have been focusing on the temperature aspects but without looking at the humidity level in the house, pretty basic. Even a relatively dry house, say 70F and 20% RH, will have a dewpoint of about 27.7 degrees F. That is fairly low and to find a point in the house that is that cold, even during design winter temperatures, indicates either a serious gap in insulation value somewhere, a very high humidity within the house or a combination of both. With 1.5" duct wrap, (compressed to 80%), 70F air in the duct, the exterior duct surface temperature would be about 56 degrees F., twice the dewpoint. Even half-inch thick wrap, slightly compressed to 3/8", would get you a sheetmetal surface temperature of about 41 degrees.... For the ductwork to see a temperature of say 28 degrees to be conservative, with a zero degree ambient in the attic (and how likely is that?), the effective R-value would have to be seriously diminished at least in spots. (It may not be all of the surface, just a few choice misses spots anyway.) Calculating the effective "balance" dewpoint assuming 70F air floating up into the ductwork and at zero degrees around it, you would have to be about 70% RH "in the duct". A slight cooling within the duct would elevate the RH (but not the absolute or net humidity quantity), but to even get that close, there has to be an elevated humidity in the home and at least some "gaps" in insulation integrity. As stated, even compressed insulation would keep the duct above dewpoint, assuming normal (low) winter RH's in the 20% or even 30% range. Point being, you have some "cover" (so to speak) and some wiggle room as to cause. I suggest some data loggers as a place to start, monitoring duct RH and temperature, house RH and temperature, over time. Do this either before or after the "fix", although it would have been great to do this over the past winter. Oh well.

Some thoughts before going much further

@ June 1, 2008 10:19 AM in VICTORIAN STEAM CONVERSION

Hi Sam- If I may raise and ask a few points of clarification? 1. Is the promise of publication the incentive here in lieu of a normal design fee? Too often a developer/owner or other entity would entice a design professional to submit schematic designs or a higher level of design on the promise of publication or other peer recognition. This is frowned upon in professional circles because it undermines the profession and gives away free design services (with waived future compensation) to be taken to completion by others. There are many good designers, architects and engineers out there who are and should be paid fully for their time and also have no problem being published as perhaps a secondary motivation or because we just like to share. :) I am not suggesting this is your motivation but because that was your lead sentence, I have to ask. 2. The second part is, why mention steam? I am not a "save steam at all costs" person but also have shown that bringing a steam system up to it's best operating efficiency is often more cost-effective than ripping out a steam system and replacing it with whatever. To replace a system with another more modern type for no other reason than the new one is more efficient by X percent has to be borne out by a life-cycle cost analysis. May be attractive, may not be. If the steam system is failing at many levels, then OK, that is a "need to do it" factor. If the piping is good, there is more thinking to be done before one jumps in. The presumption that "one-pipe steam inefficient" states a fact not entered into evidence and begs the question, "compared to what and replaced at what cost over what life-cycle cost?" 3. The third part also again asks, "Why mention steam?" If the system is to be ripped out then what was there before becomes moot. It also sets up or rather reinforces the statement that steam is inherently inefficient and was replaced because of that. The project then just becomes an application of newer technology to a structure which could as much be a 1680 colonial, a Victorian or a 2008 SIP construction house. 4. If we can presume that the envelope will be brought up to snuff, perhaps foam sealed, certainly insulated and air-sealed, that is the proven single efficiency increaser, second only to adapting or installing a new heating system appropriately sized for the new loads. Thus the "system change-out benefit" becomes lost in the overall project. 5. I do have to comment on the addition of snow melting to your listing. Absent a totally solar or other renewable energy source, my inclination is that any savings for financial or altruistic reasons in a showcase project is entirely lost when a "thermal snow-shovel" draws from the energy mix so carefully crafted otherwise. One of those things that makes me go, "huh?" That is my $0.02. Could you please elaborate on your overall objectives here?

Hey Guys!

@ May 26, 2008 10:15 AM in Welcome back Brad.

Thanks for thinking of us....*Almost* back... just using the remaining time off to square things away at our respective houses. Great time in southern VT Saturday night to Wednesday afternoon, (the Windham Hill Inn in West Townshend is highly recommended). We have abundant photos (yet to be seen) and we will post a couple and share once we get them! My bride was absolutely ravishing in a hot pink wedding dress she re-designed herself. The girls were both pretty in pink. (If you detect "pink" as a theme here, you are correct!) It feels so good to be married to your best friend. The Lovely Susan says hello. Cheers! Brad

Inverter AC

@ May 23, 2008 4:10 PM in Coming next year

is available today in the under 3-ton market with Daiken and Mitsubishi, modulating down to about 1/3 capacity. The Daiken larger systems and the Mitsubishi "City Multi" also employ inverter technology quite nicely. I am surprised that more do not currently employ inverter technology.

You are right!

@ May 23, 2008 4:07 PM in Weight of Concrete pad ?

I always get those confused, "endo" meaning internal and "exo" meaning external. I always take "endo" as being "internally generated" as opposed to the heat being sent externally ("exo"). But looking it up, the usage is as you describe. The process itself in mass is pretty neat though. I recall a large pour of magnetite concrete for a Proton Therapy center with walls two meters thick and three stories tall. The concrete took about six months to come to equilibrium. Thanks, Doug!

Typically

@ May 23, 2008 3:24 PM in Weight of Concrete pad ?

concrete, when cured, weighs 140 lbs. per cubic foot and so-called "light-weight" concrete weighs about 25% less. Water weight adds about 12 to 16 lbs. per cubic foot but as you note, evaporates in the endothermic process.

MI Cable

@ May 16, 2008 10:58 AM in Help themselves to free copper!

MI= Metallic Insulated, not Michigan by the way. You know the stuff- used to run high voltage without conduit, often in life-safety systems... The outside sheath is soft-temper copper, with a mineral barrier around the conductive copper core. Some years back, during a copper price spike, some nimrod ignored the "480V" and "13800V" labels at a Boston public housing project. (What does "V" stand for? Valuable?). Cutting into it with a pipe cutter while standing on a water pipe, our "Flash Gordon" went out in a blaze of glory I am sure. This fortunately coincided with the invention of the Dust-Buster, so the story is not entirely a sad one :)