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Brad White

Brad White

Joined on August 6, 2006

Last Post on August 8, 2006

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Setback versus Reset

@ August 8, 2006 5:21 AM in Replacement Boiler Advice

Just to be clear on the two different concepts which you may -or may not- be confusing, Eric, but also for any readers new to this: "Setback" is the reducing of a space's/zone's temperature at night and/or when unoccupied. This of course requires a temperature boost when and before occupancy again occurs. You save whenever the system does not run at all of course, and save when it maintains a lower temperature. You do spend some but not all of your savings on the "morning warm-up", so you probably come out ahead. Many variables play into this strategy and how effective it works for you at saving fuel. "Reset", or better termed, "Outdoor Reset" is the automatic adjustment of the heating supply water temperature indexed to the outside air temperature. This is a very precise way to heat a home once set up properly and this is where the most money is saved. Some system owners forego setback entirely in favor of very precise and deep/agressive reset schedules. This is typically with modulating condensing boilers. Just wanted to delineate the terms, that's all.

Mazel Tov!

@ August 7, 2006 8:14 PM in congradulations Dan

From the Lapsed Episcopalian :^)> Save money, Dan- Do what my former father in law did for me: Leave a ladder outside the window...

The best thing I ever bought....

@ August 7, 2006 8:05 PM in Sizing Floor Heat Piping

with regard to radiant system design, is the Rad Pad (available from this site and via the RPA). Of course, Dan's books, Siggy's book and lots of other things... but the Rad Pad is one of my favorite tools. (I play with it on the train and it almost guarantees me my own seat... :) ) I own two. Now, to your question: If you are using an above floor system (say Climate Panel for one example) the piping diameter will be fixed for you. Cannot be thicker than the board of course. Other considerations are spacing, depth of cover, tubing output, water temperature, floor covering R-value, tubing circuit lengths ...ALL of these things in concert... Firstly, and forgive me if too basic but your calculated heat loss is an absolute must-do before you start. From there your BTUH per usable radiant floor square footage can be derived. From that, your spacing and then your available water temperature can be derived, one may dictate the other. As an example (not checked, just for conversation), a given room may have a heat loss and floor density of 28 BTU's per hour per SF. You could have any combination of tubing at a dense spacing but with a lower water temperature, tubing at a wider spacing with a higher water temperature... but with identical outputs. If your floor topping is thin you may tend toward greater density to avoid "striping" (perceptable warm-cold zones on a given floor). This will dictate a different water temperature than a less dense layout. If your circuits are unavoidably long you may want to use a larger tube size and the smaller size tubes are more limited. Most practitioners use a 300 foot mazimum for most tubing sizes but for 3/8" (10 mm), 150 to 200 feet maximum... So you can see how all work together as a system. Do yourself a favor- buy a Rad Pad and play with it. It gives abundant "what-if" scenarios that will answer nearly any question you may have. Not like the "Magic 8-Ball" or Ouija Board of course, but those too will get you your own seat on a train. Brad p.s. I do not work for anyone who remotely sells or promotes the Rad Pad nor do I have any financial stake in any product or system I may recommend. Full disclosure here.

@ August 7, 2006 7:50 PM in New T-shirt


Floor squeaks

@ August 7, 2006 7:49 PM in Joist Blocking

Generally, floor squeaks are a function of how well the sub-floor is bonded to the joists. I do not know the floor loading but 2x8's do not strike me as being excessive in span especially if 16" OC. Not a lot of room to twist, if you can picture that also. My inclination would be the dragon teeth to be sure or in the alternate and if the underside of the joists is not in a finished space, lag-bolt a 2x4 across the bottoms of the joists perpendicular to them. I did this in my own house for different reasons. It did make my floor stiffer but that was also a function of putting in a bearing partition below... Full 2" x 8" lumber from the 1870's spanning 22 feet I kid you not... and spacing? Whatever the distance from elbow to wrist it seems. Not indicative but at extremes it worked. Cannot hurt otherwise. I know you are good and you will do the right thing. Let me know what you finally do, if you do not mind. Brad

If I may expand on that

@ August 7, 2006 7:43 PM in Runtal baseboards

I agree the "radiator bottom to floor" dimension has some give to it. The key principle being that the distance behind the unit (about two inches including unit total depth) should be allowed from bottom of the radiator to the floor. This is so as not to constrict airflow especially if you have the fins (lamelles) which afford higher convective output. As lchmb has said, this can be done and works fine; it just may not conform to the laboratory conditions under which they were rated. The concept of using these at the end of a run of fin-tube rather than the beginning is to preserve the hottest water for the fin-tube. With the higher radiant output of the Runtal, it is more forgiving of lower water temperatures. Just an elaboration on the point mentioned. I have it in my house among some cast iron units. Each radiator of either type is piped individually, not in series and with TRV's (thermostatic radiator valves) on each. They heat quickly and evenly. Viv, your comment about needing higher output in the far north would have me add that the radiators -of any type- should be sized for a calculated heat loss AND for the expected water temperature you will send out on the coldest day. From here you can plan a reset schedule (automatic outdoor reset) which will save you money.

Yes we are not crazy...

@ August 7, 2006 7:33 PM in Steam/water's boiling point??

Not vapor so much as vacuum systems can achieve fast heating albeit at a lower temperature. I do not know if varying the vacuum to make it a form of outdoor reset has ever been tried.... If Steamhead says yeah or nay, then it would be so.... The vacuum systems I have worked on (often courthouses and post offices built in the 1930's) had issues maintaining normal vacuum range, perhaps 4 to 8 inches of mercury ("Inches Hg.") We were lucky to maintain three inches... At the "ideal" standard of 5.5 inches, this was a reduction of about 2.7 psig, so the steam would be at 12 lbs. absolute and would have a temperature of about 202 degrees, F. However, each pound at that pressure would have a heat of evaporation of 976.6 BTU's compared to 970.3 at atmospheric pressure and 968 or so at 1 psig. Not much difference we agree but properly run, those systems heated very quickly. Of course the radiators had to be sized for lower temperatures. EDIT: Useless but fun trivia: Never say "vacuum" to a deaf person. :^O>

Depends on the flooring system

@ August 7, 2006 7:16 PM in Joist Blocking

Engineered lumber has their own criteria but the older stick framing x-bracing (how tedious was that?) at least lets you snake through. My Susan's house, 1922, (the house, not Susan), has that and the ease with which you can wiggle them tells me that they are not doing too much. I had an old-time carpenter tell me that bracing or blocking really did nothing provided the sub-floor above was properly secured and the bottoms of the joists were joined at support points. The notion of the joists twisting when so secured even without bracing was far-fetched. The bracing was held with nails driven by a hammer at marginal force... driven in an "s" curve if you were good. But, I am a softy for redundancy. I would replace any blocking or bracing with the stamped metal "dragon teeth" kind of X-Bracing made by Simpson or others of that type. You can still snake by with tubing and also have some clear opportunity to grind down those nails. Engineered lumber systems? I do not know. I would ask someone else. This is just my $0.02

I just knew Steamhead would know....

@ August 7, 2006 6:25 AM in main vents advice

I particularly like the comment about the "accessory 80 year old house", Chuck. Your priorities check out just fine! Brad


@ August 6, 2006 10:14 PM in Old Stuff

Looks like an Aerofin coil also used by Buffalo Forge and still available I think. The fins were turned off of heavy wall soft tubing on a pattern lathe then fitted to headers. Sometimes the entire assembly would be "solder-dipped" and that may account for the silvery color. The fin-to-tube bond is inherent with that manufacturing method.

I agree with John

@ August 6, 2006 6:47 PM in hydronic register loop length

I would have tried to work with the existing boiler and replace it only if on it's last legs, but also if replaced it would be sized to a calculated heat loss. The 75,000 BTU boiler would seem at first look to adequately heat an 1810 SF insulated home in zero degree weather (33 BTU's per hour per SF if 80% efficient seems reasonable to me.) A single 414 foot loop?? So if you get too warm you move toward the end of the loop and if too cold you move to the beginning? What a concept. No way to live. I would have a very pointed conversation with the contractor, hold all retainage and use the manufacturer's recommendations as a lever. Regardless of contracted details, installing material contrary to a manufacturer's listing tends to prevail for your side in arbitration if it comes to that. As a matter of your path to correction, here is one experience I had some years ago: I investigated and fixed a similar issue (not so egregious as yours seems to be) in an expanded ranch house with over-extended baseboard, probably double the element which the pipe size could support. The fix was to split the zone and feed one of the most heavily glazed rooms (floor to ceiling glass and formerly the coldest room) first. What we would hope for you is that the piping can be intercepted from a basement or crawlspace directly below. The heating elements are an issue on their own. Without seeing them, replacement may well be required. Want to know who to believe? Most any of us here. You may see occasional differences of opinion but within that, consensus. Good Luck- Brad

Excellent point, Larry

@ August 6, 2006 6:33 PM in Insulation = reduced efficiency?

We both know that infiltration is often the single largest category of heat loss especially in a house that is well insulated. Blower door tests and sealing indeed pay huge dividends. I wish that they were more mainstream and commonly done.

Is there glycol in the system?

@ August 6, 2006 6:29 PM in Whistler

If the glycol is too rich a mixture, there is a surface boil-off condition whereby the water in solution but in contact with the heat exchanger opposite the flame-side, will have a film of fluid that will come to a boil. Moaning and wailing often result. Just a thought.

Unicquely, Techman,

@ August 6, 2006 6:24 PM in technical reference for sizing high velocity a/c system

Unicquley indeed. :)

Burnham Heating Helper Publication

@ August 6, 2006 6:21 PM in Commercial Greenhouse Heating

One thing I found is on page 52 of the on-line Burnham Heating Helper in PDF format. One page dedicated to greenhouse heat loss calculations- I mean, there are hundreds of applications besides houses and buildings... someone at Burnham saw fit to include... greenhouses... Just found that interesting...

Just kidding of course, JR...

@ August 6, 2006 6:14 PM in Will wallies be the new dead men?

I will send you a copy of my portfolio for your blessing, and lunch when we meet.

Glad you like it!

@ August 6, 2006 6:12 PM in Sequence of operation

Just expanding on the concept, you can have a nice label made on your computer with company logo and a short video of any walk-through, service or just, "Hi, I am Josh the designer and installer of this system... ". Years from now you will be a legend more than you already are.. In my business (consulting engineers) it is the contractors who do the O&M manual preparation and the CD is just a part of that. Great age we are living in!