Joined on March 25, 2009
Last Post on September 20, 2013
@ September 20, 2013 2:59 PM in Help with using Navien in a primary/secondary loopSure seems like a lot of flow...
@ September 20, 2013 2:12 PM in Staple Up Radiant - Old House, Is this possible?That's a lot of heat loss. Even under the best circumstances a heated floor can only provide up to 35 BTU/sqft due to surface temperature limit recommendations, and yours are not the best circumstances so even that may not be attainable. 1.75" of wood is no small barrier to heat flow. To boot, the subfloor is probably cupped and there are gaps in it so contact between heat transfer plates and it might be tenuous. There's a system (UltraFin) that uses little convective plates that snap onto the PEX tube that's suspended a few inches below the subfloor in the joist bay, which would not be vulnerable to irregularities in subfloor but would require that the joist bays be sealed really well at the perimeter to prevent heated air leakage. Bare PEX tube, regardless of size, is not likely to be able to transfer enough heat to be a primary heat source in any non-superinsulated house in a Northern climate.
And then, as I indicated in the subject, there are radiant ceilings, which are a good retrofit option. Search for that term on the site and you'll find out a lot about the pros and cons. These typically, but not necessarily, involve furring out the existing ceiling and stapling thin plates to the furring strips, snapping tubing into them, and then sheetrocking over the entire kit'n'kaboodle.
@ September 9, 2013 3:21 PM in Using a combustion analyzer on an engineI thought that perhaps this had something to do with exhaust pulses. So is it the pressure fluctuations themselves, rather than the air they draw in, that would throw the readings off? If it's just dilution, it seems like I should be able to adjust. Or simply find the peak CO2 and know that I'm stoichiometric, and then richen a bit...
@ September 9, 2013 7:49 AM in Using a combustion analyzer on an engineI recently repowered a garden tractor with an LPG engine and I thought I'd check combustion to see if it needed tuning. This is just an air cooled engine with a simple venturi, no electronics at all, so you have a single screw to tune the mixture - just like a boiler, right? :-) Unlike a boiler, however, you're supposed to tune these to 14% CO2 and .5-.75% CO - that's 5000-7500 ppm! I stuck the probe inside the exhaust port as far as I could, and I can't get any readings that make sense. CO2 is reading at .2 - 2% (measured), O2 is reading at 20-18% (calculated based on lean mixture, I expect this to be wrong), and I know that I'm not anywhere close to that lean; the engine wouldn't run. The only reading that makes sense is CO (measured), but I'm not even trusting that one given how screwy the others are. Besides, the UEI SmartBell Plus that I'm using is only supposed to have a range up to 2000 ppm, even though it was reading out over 6000 ppm at times.
So... combustion being combustion, any ideas about why my CO2 reading is so off and how to improve it?
@ September 5, 2013 11:35 AM in Help with fitting...For copper to iron, use a brass fitting as a transition. Use teflon tape and pipe dope on the iron-to-brass joint to prevent galling.
@ May 2, 2013 10:03 AM in Rumor has itI mean that it's a fairly big box and you have to have room for the entire big box. In retrofit applications this may not always happen. In reality, it probably takes up less space than the equivalent system built out of parts. I hear you on people moving mechanicals out of the basement; hadn't thought of that since I'm far from any flood plane. I had actually looked at whether it would be possible to import a 333 some four years ago or so; at that point the 300 series were the only ones with lambda pro, they had better turn-down, the bus circulator, and were available with an actual indirect rather than flat plate + storage. That's how much I liked the concept - for myself. I decided that it was too scary to completely foresake any product support, even if it's something as solid as a Vitodens. ;-) So I'm not pooh-poohing the product.
@ May 2, 2013 7:35 AM in Rumor has itIt has built-in storage (27 and 35 gal). It looks like it's meant to be a system-in-a-box. But it's a big hunk o' something! On the one hand, I can see the benefits of a well-integrated system... but, on the other hand, there are disadvantages, too. It is likely more expensive than something you'd build out of components, both up front and (especially) when something needs replacing. Also, you have less flexibility with tailoring the system to its various functions. And you have no flexibility with locating various bits to suit the space constraints. Let's face it, nobody in North America will put this thing in their kitchen or even bathroom, it will be in some corner of the basement where it has to fight for space with wiring, plumbing, and cat boxes.
@ May 1, 2013 11:43 AM in Taking out a 3 yr old Navian..What boilers have this wide a gap between return water temps and stack temps? I typically see a few degrees difference max on fire tube designs.
@ April 30, 2013 7:13 AM in I do not just work on steam boilersAnd a manifold site-built from black iron pipe... must be an old timer. ;-)
@ April 27, 2013 9:10 AM in National Plumber Day!I guess you could wire an outdoor reset control to some device that would make the steer stand up, as this would expose more surface area and produce greater heat output...
Maybe we could breed steer for increased surface area relative to volume. At the extreme end of that, you could imagine a living cowhide rug.
@ April 27, 2013 7:29 AM in navien and odr?But it seems that you can make this zone just fine even if it doesn't support both a heat demand input and the indoor feedback unit, just as long as you place the indoor feedback unit in your "most difficult" zone. This will then be the only thing that drives your system demand, and thermostats in other zones will only open zone valves for their zone without any feedback to the system. This is the same way TRVs are usually employed - since they don't have any end switches on them. :-)
@ April 25, 2013 7:36 PM in Very NiceYou'd have to ask the people who wrote the manual. They contradict it in at least two different places.
If they could turn it down to 2', would you set it that way? That would be a good way to make sure that your higher head loss zones don't get the flow they need. Or you could balance your branches and have appropriate zone flow regardless of total system demand. Yes, I know, people don't balance their circuits, they don't do heat loss, they don't use outdoor reset or set it correctly, they don't calculate flow and head loss, they don't glue or prime their venting, they don't use oxygen diffusion barriers, they don't pump away... sheesh, scorched air is starting to sound pretty good! Luckily, now we have a product that will single-handedly right all these wrongs. But will it put down the toilet seat after someone leaves it up?
@ April 25, 2013 1:31 PM in Very NiceIf it were set with H=5, then shut-off head is 4.5 and the pump would circulate roughly 1.5 gpm through that little zone. The zone would be overpumped by 50%, in other words. But that zone would be overpumped by as much even when all the zones are calling. And it would be overpumped by as much at near-design conditions no matter which circulator you use (yes, even the Bumble Bee) for one simple reason: flow has not been appropriately balanced.
@ April 25, 2013 10:17 AM in Very NiceWhat happens to the Bumble Bee if you just put it in out of the box?
Or are you suggesting that figuring out where to place the two temperature sensors and how to plug them in is simpler than twiddling a dial? Yet, in the blog posts about dT, I don't see any analysis of what will happen if you just install this excellent product in an out-of-the box configuration - sensors detached - without bothering to read and understand the install instructions. Shouldn't he be more concerned with the proper installation of his own product than the competitor's? Why harp on this when a simple paragraph would do? Here's the suggested wording of that paragraph: "As with any control strategy, the benefits of pressure differential-based variable speed circulation will only be realized if the appropriate curve is selected. If set too high for the system, the variable speed circulator may constantly operate at full speed and overpumping may result, as illustrated in Figure X." A good location for this paragraph would be at the end of an article that honestly describes dP operation when parameters are correctly set.
We won't even mention the Alpha, a dP circulator that comes with the factory AutoAdapt mode selected.
It is the author's prerogative to write anything he likes any way he likes. All things considered, however, I find it impossible NOT to gain the impression that the way he chose to write this pooh-poohs a competing technology unfairly.
@ April 25, 2013 7:58 AM in Very Nice...with his choice to stick to his guns on analyzing what a misconfigured competitor's product does before he ever gets into what it will do if (presumably) correctly configured, and use the out-of-the-box clause as a cover.
Here's a realization: out-of-the-box, no circulator does anything useful except maybe act as a paper weight. You still have to, ahem, install it. Plugging it in is good, too. I'm surprised that this series of articles takes such a critical thing for granted...
@ April 25, 2013 6:48 AM in Very NiceI'm bashing the article. I see no evidence on this thread of bashing dT or setpoint circulator control, Taco, or its products. Seems to me like we all agree that there's an application for dT. (As an aside, as far as the setpoint mode is concerned, you could make it far more useful by using the other sensor as an outdoor sensor and providing a way to set a reset curve, which seems like it would be a software-only upgrade. But that's just my opinion.) But the article would certainly appear to bash dP circulator control, and do it in a fairly unfair manner. Anyone with a concern for the health of the industry and the passion for technology that John has surely aspires to a higher standard of fairness and accuracy.
There's a difference between stating that there's a target delta T for design conditions that's a good compromise between cost, energy efficiency, and performance, and that there shall be a fixed delta T for all conditions. I, for one, would like to see him discuss more broadly the implications of a fixed delta T operation compared to floating. He hinted at it in this article (suggesting that a dP circulator would run at the same speeds during shoulder seasons as it would during peak season) but a balanced and in-depth analysis of the two approaches (maintain flow but reduce supply temp further [floating dT] vs. reduce flow but reduce supply temp less [fixed dT]), both ways to attain the same AWT and therefore the same heat output, is what it's really called for and what has driven a lot of the discussions here. He may find it necessary to tweak his format a bit.
@ April 24, 2013 4:07 PM in Very NiceThere are other products with clearer manuals out there. Also, as an expert, or at least a person with considerable expertise available to him at will, he should be far less dependent upon these manuals to figure out how these devices should be set. As a person of authority in this space he has a responsibility to the industry to present accurate information. I'd be far more inclined to cut slack if the tone of his article did not strike me as pretty condescending to the unwashed masses who are honestly trying to make sense of this technology (and apparently having more success than he, the expert.)
@ April 24, 2013 3:47 PM in Very NiceLooks like shutoff head is not really H/2 but more like (H + Hmin)/2. So, rather than split the difference between H and 0, split the difference between H and Hmin. What this would mean is that at H=5 (which would be a good setting for this system) you'd basically have a near constant dP curve.
@ April 24, 2013 2:58 PM in Very Nice1/2 H is then 2' head. That's the shut-off head. For the circ to operate the way you describe it would have to be set for 8'. By default, it is set to 10'.
@ April 24, 2013 2:28 PM in Very NiceMy point is contained in the last sentence. Why would you intentionally misconfigure a product just so you can state that it doesn't perform?
Yet that, in my view, is what the blog's author did.
@ April 24, 2013 2:26 PM in Very Nice...that dial is there so you can turn it up too high and then complain that the circ is operating at full speed and you're overpumping your system. :-)
Chris, I updated my original response to this thread with what would happen to the circulator's duty point if it had been properly set up for this system. I hope that answers it.
@ April 24, 2013 1:27 PM in Very NiceThe Alpha is only dP-constant. Larger Stratos circs (among others) support both. The blog author was using the Eco in the context of dP circs in general.