Joined on November 26, 2011
Last Post on December 4, 2013
@ December 1, 2013 12:33 PM in Midco Low-Nox Burner Performance ReportI've been eying the Midco burners and am glad to see some realworld data.
I think of anticipators as a workaround for the limitations of bang-bang control. PI is so much better at avoiding over/undershoot.
@ December 1, 2013 11:58 AM in want feedback piping WOOD boiler gas mod/con backup via reverse indirect BUFFER tankExactly, which is why you need to size the buffer tank as I described above.
@ December 1, 2013 11:47 AM in Midco Low-Nox Burner Performance ReportI'm curious whether you're using a thermostat contact closure or a sensor for the indoor temp?
@ November 30, 2013 4:06 PM in Maximizing efficiency of a mod con questionhave an aux output which can be configured for ∆T modulation of the boiler pump. This pairs nicely with a Taco VVF pump, hence my suggestion above. Turns out I got the model number wrong and the stainless version is the same price, so I'd probably choose a 003-VVST4 for this if I were keeping the primary loop.
@ November 30, 2013 12:23 PM in Hot water baseboard heatingagree that a 008 is a better choice than a 0010. I'm going to see if I can pry some curves out of HTP just for fun.
The Bumble Bee (HEC-2) has almost the same curve as the 008 and only costs a few bucks more. I'd probably choose one of those.
@ November 29, 2013 10:03 PM in An Epic Tale: I hear the Trane a comin'!Keep sending pictures, and good luck!
@ November 29, 2013 9:37 PM in Maximizing efficiency of a mod con questionand one of the things you've just learned is that heat loss calculations already have a generous fudge factor built into them. Remember that the "minimum" flow rates in the manual are only required at maximum boiler output. If your actual load is less, the boiler's maximum demand will be lower. The other 99% of the time it will be even less. The low head loss of that HX presents you with an interesting challenge: finding a pump that's small enough. Full fire needs 4.6 GPM for a 35ºF ∆T, with the HX offering about 1/3rd of one foot of head resistance. A Taco 003B-VVF should play well with the Lochnivar controls. I really wish B&G/Laing offered the ecocirc e-Series with 0-10V input.
@ November 29, 2013 6:13 PM in Hot water baseboard heatingWhether 11 feet of head is realistic at 7.3 GPM. If Table 7 applies to multiple models (unnecessarily confusing IMO) the 11.3' it shows must be for an SSU-30. Otherwise, how can the head loss possibly be greater at 7 GPM than it is at 10 GPM?
Does HTP have curves available?
@ November 29, 2013 5:48 PM in want feedback piping WOOD boiler gas mod/con backup via reverse indirect BUFFER tankfor liquid or gaseous fuel boilers is based on those factors. For a solid fuel boiler you need to look at the total capacity of a fully loaded boiler and use that combined with the tank ∆T.
How many pounds of wood can you fit in the firebox? Multiply the total BTUs in that load http://chimneysweeponline.com/howoodbtu.htm by the efficiency of the boiler (percent) to determine how many BTUs the boiler will produce in a complete burn of a full load of wood. If you burned 100# of 20% moisture wood like the example in the link above, yielding 6,200 BTUs per pound, you would have 620,000 BTUs to store. This is not BTUs per hour, this is just BTUs. Assuming for a moment that your floors can make use of 85ºF water on a mild day and the tank/boiler/PRV will allow 180ºF to be safely stored you have a ∆T of 95ºF for the tank. 620,000 BTUs divided by 95ºF can be stored in 6,526 pounds of water (almost 800 gallons.) You can subtract the building load for a mild day over the course of a complete burn (BTU/hr x hours = BTUs) from the total if you want. I generally start by assuming the possibility of overt stupidity on the part of a clueless future owner and assume they will need to store everything that is produced in a full load of the densest fuel they have around when the heating system is off.
@ November 29, 2013 5:21 PM in Hot water baseboard heatingon the indirect loop? It's still possible I'm missing something here, but why?
@ November 29, 2013 4:34 PM in Hot water baseboard heatingshows pressure drop at recommended flow rates, but only @10 GPM for the SSU-45 as far as I can tell. Using their number of 141,000 BTU/hr I get an assumed ∆T of 28.2ºF If those are boiler output figures, the 72,000 the Alpine 080 would only need 5.1 GPM with that ∆T. Assume a bit less, say 20ºF, and you get 7.2 GPM. I suspect that somewhere in between lies a flow which will deliver all the BTUs that boiler can produce.
@ November 29, 2013 4:24 PM in Have nay of you installed a Dettson electric boiler ,don't cost all that much. Thermolec is another Canadian brand with a good track record (and their stainless pressure vessels don't weigh a lot.) For the task you're describing, I'd be inclined to see if the factory or my rep could scare up an older model or a demo and hack up some switches to cut elements in and out depending on the available power at the job.
@ November 29, 2013 12:09 PM in Hot water baseboard heatingat 10 GPM means less at 8 GPM. I don't see any HX curves in the SSU IOM and I can't really make sense out of Table 7 given that it shows higher head loss for 7 GPM than it does for 10 GPM. Perhaps it represents multiple models? Whatever it is saying needs clarification.
At this point, I'm not saying an 007 is adequate (though it may be) but I do believe that 10 GPM is not necessary given the size of the boiler. If row 1 (6 GPM) of Table 7 happens to apply to the SSU-45 then an 007 should work, but a 008 (or better yet, a Bumble Bee) would probably represent a better choice.
@ November 29, 2013 11:07 AM in want feedback piping WOOD boiler gas mod/con backup via reverse indirect BUFFER tankshould be sized according to the maximum BTU output of the boiler from a full load of wood. The BTU/hr rating determines the size of pipes and pumps, but the tank should have the capacity to absorb the full output of the boiler when there is a minimal load (e.g. a mild fall day where you need just a bit of heat to keep the place comfortable.) The capacity of the buffer tank is determined by three things:
The size (in gallons) of the tank.
The maximum temperature of the tank.
The minimum useful temperature of the tank (which depends on the emitter design and building heat loss.)
@ November 29, 2013 10:51 AM in Hot water baseboard heatingfor 10 GPM when the boiler maxes out at 72,000 BTU/hr. Or did I miss something?
@ November 29, 2013 10:48 AM in want feedback piping WOOD boiler gas mod/con backup via reverse indirect BUFFER tankare you using plates? Insulation? Just curious.
http://www.caleffi.us/en_US/caleffi/Details/Magazines/pdf/idronics_10_us.pdf will teach you more about wood boilers than you ever wanted to know. I'd start there.
@ November 29, 2013 10:24 AM in Two Pipe Steam - Air Vents and some other confusionseems to require a bit of creativity, but the results are clearly worth it.
I'll ask again -- is there any reason some of this ingenuity could not be applied to a conventional two-pipe system (using currently available parts) to produce a kind of modern "vapor retrofit"?
@ November 29, 2013 10:12 AM in Have nay of you installed a Dettson electric boiler ,but it looks like a nice unit. The challenge for temporary use will be wiring, especially for the larger units -- though it takes a lot less to prevent freezing than it does to heat a space to a comfortable temperature.
@ November 29, 2013 12:20 AM in Hot water baseboard heatingWhy size the pump for the maximum the tank can absorb when the boiler only puts out half of that?
@ November 28, 2013 11:22 PM in Burner retrofit for scotch boxDDC is almost certainly in your future, but if you can find a way to keep what you have working for a few years, by all means do so. Take the next couple of years to educate yourself on everything you can about DDC, especially about the business practices and "plays well with others" characteristics of both your local installers and the manufacturers they represent.
@ November 28, 2013 12:48 PM in Pipe Dope&Tape:Is this OK?are available from quite a few companies. Loctite has a big advertising budget.
http://www.fppi.com/products/list/139/pipefit-as-thread-sealant-paste.aspx is rated to 400ºF and is priced right.
@ November 28, 2013 11:58 AM in Delta t ?Not sure how either the house or the zones are laid out, but if you can find a way to link all the loops subject to solar gain together and have them respond to that stat it will likely improve the overall system balance. You'll have to tinker with the minimum floor temp setting on the 519 a bit -- I'd start a couple degrees above the lowest temp you're seeing now and see how it recovers.