Joined on November 26, 2011
Last Post on March 6, 2014
@ February 26, 2014 1:27 PM in Short Cyclinginclude this already. Just match square feet to square feet (most of the time.)
@ February 26, 2014 12:36 PM in Logamatic 2107 or Tekmar 260 ?is different than surge or TVSS protection. By far the best place for a TVSS is at the service entry, connected via a short, low impedance path to a good earth ground. Additional TVSS protection, if used, should be installed at potential sources of noise as well as at sensitive equipment. Good power supply designs include onboard surge suppression (usually MOVs, sometimes transient diodes or gas discharge tubes) and the entire device will be tested to at least 6kV.
The combination of an isolation transformer with a capacitor creates a low-pass filter which simultaneously prevents HF noise from getting in (to the equipment being protected) and out (from the HF current spikes created by a switch-mode power supply.) It will also "round off" the modified squarewaves generated by UPS inverters -- at the expense of a small efficiency loss (the extra energy is converted to heat and/or noise.)
Most "SPD with low pass filter" designs place an inductor in series with the line. The size of that inductor is limited by cost, which has the effect of presenting a high source impedance to the load, which will actually increase line noise.
@ February 24, 2014 12:37 PM in friction lossReducing flow and increasing ∆T will result pretty big wins both for first cost and electrical usage.
50 GPM = 42.4 feet (say 20ºF ∆T)
40 GPM = 27.9 feet at 25ºF ∆T
30 GPM = 16.3 feet at 30ºF ∆T
@ February 24, 2014 10:21 AM in The best Delta T for a mod-con?Set the stat for 85ºF and leave it there for a few weeks. Adjust the ODR curve and balance your emitter flows until your indoor temp remains stable across the full range of outdoor temps.
The posts above contain some misinformation.
@ February 24, 2014 10:03 AM in Help with Steam EfficiencyAlan? Not sure who else to suggest up there, but you should at least review these before signing anything
@ February 24, 2014 9:57 AM in Big problem with even heat distribution, please please help!That boiler could be converted, which would reduce your fuel bills rather dramatically, especially with proper venting.
@ February 24, 2014 9:39 AM in Heat Transfer Plates over Onix?I'm curious...
@ February 21, 2014 9:14 PM in Advice on Rare Old School "Dual Flow/Bypass" Radiator Valvehttp://www.heatinghelp.com/files/articles/1213/140.pdf
p.13 of http://www.heatinghelp.com/files/articles/1014/105.pdf
@ February 21, 2014 8:57 PM in Help!! staple-up insulation foil mythCall Watts Radiant and ask them what's compatible. I suspect their new FlexPlate might have been made for it. It's also possible that some U-plates will work.
@ February 21, 2014 1:03 AM in Scott's radiant heating projecthttp://www.lochinvar.com/products/default.aspx?type=productline&lineid=202 Giannoni heat exchanger, far simpler controls than the current Knight line, but attractive prices and (in the CD*040) the smallest mod/con with the lowest minimum modulation rate available in North America.
@ February 20, 2014 10:56 AM in Pictures of existing system that needs replacementare regularly carried into basements one section at a time.
@ February 19, 2014 11:42 PM in how prevalent is this?once the MMM moderation machine has had a chance to digest your post. A number of posts already mention Mark. Both Weegie5 and Kenoryn posted links to Radiantec, a site with a well-documented history of flaunting accepted industry practices, building codes, and the occasional law of physics.
@ February 19, 2014 11:24 PM in Not Enough Radiation?What were the room temps like with the old boiler, as compared with other rooms in the house?
@ February 19, 2014 11:02 PM in I've been going over Señor Gil's venting values. Again.http://www.engineeringtoolbox.com/ansi-steel-pipes-d_305.html for steel pipe. Note the "internal transverse area" column.
@ February 19, 2014 10:56 PM in Steam utilities (Excel)to Google Drive (used to be Google Docs, and/or Google Spreadsheets) with full control over who can see, edit, comment, etc.
@ February 19, 2014 10:39 PM in Heat Transfer Plates over Onix?the Watts FlexPlate (flexible graphite heat transfer plates.) I was not impressed with the minimal contact they achieved with 1/2" PEX, but Onix has a larger OD (which I'm now thinking the FlexPlate may have actually been designed to work with.)
@ February 19, 2014 10:42 AM in Which of these two setbacks is more economical?And I'm actually not opposed to setting back the water temp from the boiler to see how it all works and feels. My experience is that setting back a thermostat with a tight ODR curve is generally an exercise in futility.
Note that there's still more stuffing inside a mod/con boiler than a tankless. The methods of modulation are quite different on most gas tankless as well. Then you factor in the sales volumes and the distribution channels and it starts to make some sense.
@ February 18, 2014 9:13 PM in geothermal vs. airsourceon modern VRF ASHPs are competitive with those on older GSHPs. The latest batch of GSHPs with VRF have raised the bar even higher. I would suggest a consultant, engineer, or contractor who is up on the latest offerings as the field is changing.
@ February 18, 2014 8:37 PM in Triangle Tube Indirect vs HTP SSU Indirectare where the SMART indirects really shine. Turbomax handles high demand applications quite well; on hard water the SMART still outperforms the field by a wide margin.
The stainless used for the inner tank does not like high chlorides.
The carbon steel outer tank is not compatible with open systems (most outdoor wood boilers, many drainback solar systems.)
The issues Ice ran into above are a side effect of that portion of their design which allows them to mostly ignore hard water. Make an informed choice.
@ February 18, 2014 12:05 AM in boiler sizeand room-by-room heat loss will tell you whether this is true or not. 85k output gives you 44 BTUs per square foot, which is quite likely oversized itself.
@ February 17, 2014 11:51 PM in how prevalent is this?and mostly covers the bases.
> A comprehensive control strategy needs to be developed and tested to optimize the control of heating pump flow, air handler flow, and TWH heating output, to control on heating water return temperature, heating SAT, and DHW supply temperature to better optimize and monitor efficiency and comfort of specific combination systems.
Last time I checked, much of this hardware and software were included with the best of current mod/con boilers.
> There are really no standards or peer-reviewed guides for efficient combination system design. Most systems are designed and installed by trial-and-error “experts” from smaller independent heating system companies.
Not really sure what to say here.
@ February 17, 2014 11:07 PM in Which of these two setbacks is more economical?> The main relevance to not setting back, as i understand it, is if you
could run at a low mod in condensing mode the whole time
The "main relevance here" is that recovery from setback requires a boiler sized larger than the design load.
> My understanding of thermodynamics here is that the mod alone mostly
saves short cycling on less than full load, it doesn't raise efficiency
of op without employing condensing mode
Modulation more closely tracks the load, reducing standby losses. As the return water temperature drops, efficiency increases. At some point along that curve, flue gas condensation begins. The exact point at which that happens is a fraction of a degree below the last point at which it was not occurring. There is nothing fundamentally different about those two points (the way there is for something like a phase change.)