Joined on April 11, 2007
Last Post on April 19, 2013
@ April 19, 2013 11:06 AM in Boston Tragedy Hits Closer To HomeReceived this from a colleague this morning - was on the radio news this morning:
An update to Jeff Bauman's story -- it was reported on the radio today that Jeff, even under sedation and in massive pain, tubes down his throat , helped the FBI sketch artists with a description of one of the guys he saw drop the backpack. From that sketch description they were able to focus in on all the video film and target the suspects.
@ April 17, 2013 9:28 AM in Boston Tragedy Hits Closer To HomeSaw this on Facebook this morning -- a young fellow named Jeff Bauman was badly injured in Monday's bombing at the Boston Marathon. Jeff wound up losing both of his legs.
Jeff's brother Tim works for Eric C. Foster Plumbing and Heating in Chelmsford, MA so in my book, that makes Jeff one of the "family." I"ve known Eric for a lot of years and he runs an outstanding business.
They've started a fundraising website to help defray what is sure to be a mountain of medical bills coming the family's way. Please keep Jeff in your thoughts, and if you can, help the family out.
Here's the link to the fundraising website: http://www.gofundme.com/BucksforBauman
@ February 20, 2013 2:04 PM in How would you control a Bumblebee circulator in a pure TRV situation?Just because the pump is "smart," it doesn't mean the person using it doesn't need to be!
@ February 20, 2013 12:06 PM in How would you control a Bumblebee circulator in a pure TRV situation?I've seen those plots as well...and one thing I can't quite figure out, and what no one has been able to adequately explain to me...is that heat output droops with a fixed speed circulator as well and, according to the charts, would't "work."
Not sure what that means, but it must mean something...
@ February 20, 2013 12:02 PM in How would you control a Bumblebee circulator in a pure TRV situation?...it is a contrived example, and contrived examples ALWAYS make one's point ;-)
I mean, who would contrive an example that disproves his point?
Delta-P was designed for this type exact application - and it works very well, there' sn o dispute there.. But Delta-T works well in this situation, too. As I said, I lived with the exact example you mention yesterday, just to see what would happen - a fairly realistic setting. Was it an entire heating season? No, just one freakin' cold day in Minnesota. The circulator seemed to be just fine with it all...because one TRV does not a system make. There are a bunch of them...and water temperature doesn't make them throttle, room temperature in the vicinity of the operating head does. And I'll bet dollars to donuts my ODR curve is probably a bit high for the real heat loss of the house. I calculated it to 44,000, but I'll bet it's lower than that in reality...
And again, the Delta-T pump does not set or control the supply water temperature - that may be the element you're missing - it doesn't even care what the supply water temperature is. It only cares about the Supply-Return difference. BTU requirements change - if the Delta-T is maintained, the system flow rate will change accordingly.
I think, Gordan, we may be at the point where we shake hands and agree to disagree...
@ February 19, 2013 8:28 PM in How would you control a Bumblebee circulator in a pure TRV situation?Just need to get that machine from "Honey, I Shrunk The Kids"....
@ February 19, 2013 6:48 PM in How would you control a Bumblebee circulator in a pure TRV situation?Hi Gordan –
Had to laugh at your opening line – can’t hear or read “with all due respect” without thinking of Ricky Bobby!
I think if you look at a snapshot in time, you’re very correct about how TRV’s affect AWT in a panel radiator. But think about what causes a single TRV to “throttle down?” The thermostatic head is getting closer to being satisfied – meaning it’s getting warmer in the room – meaning less output is needed from the radiator – meaning your reaching a point of relative equilibrium for the radiator - meaning fewer BTU’s are being taken out of the fluid – at that particular snapshot in time.
Give it a minute – and that equation will change.
Nothing remains static for very long in a panel radiator system. That TRV continues modulating in an effort to maintain a comfort level in the room. And what’s more – every other TRV in the house is doing the same darn thing, all based on their own settings, heat loads, radiators sizes, etc.
Cross purposes? If you look at one snapshot in time – yeah, you’re probably right. But heating systems are more like a full-length feature film than a snapshot. Look at what happens over the course of 10 minutes, 30 minutes or two hours, and consider what’s going on with all the radiators in the entire system (their TRV’s are probably doing different things at different times), and remember that a Delta-T circulator reads the difference between the water temperature going out to the system and the water temperature coming back from the system – key word being “system” – and will vary its speed to maintain that overall system Delta-T. If one radiator out of a dozen has a closing TRV, I can’t see that it would “confuse” a Delta-T circulator.
One more note – the circulator doesn’t care what the supply water temperature is – just the difference. Set that Delta-T for what makes the most sense for the application.
And just for giggles – since it’s about 4 degrees here in Minnesota today – I shut off the open radiator in the family room, turned my BumbleBee on continuous and let it operate on just the TRV’s on the rest of the radiators. Nothing blew up, the circulator hummed along between 9 and 14 watts (that I recorded – may have gone lower or higher while I was in the can), the boiler was happy and the downstairs (except the family room) was fine. Left it like this for about 4 or 5 hours. I don’t know what that means, but it means something…
At the end of the day, it’s kinda hard to get around the simple fact that GPM = BTUH ÷ (DT × 500).
BTW – I think you misread something. I said that people tend to like continuous circulation systems for electrical “simplicity,” not electrical efficiency. No relays, no thermostats, etc makes for a pretty simple system. That said – my own personal opinion – and it’s just that, my opinion – is that I’d just as soon turn a pump off when I don’t need any heat. With properly sized heat emitters and outdoor reset – you’re gonna have fairly long on times, anyway…
@ February 18, 2013 9:43 AM in How would you control a Bumblebee circulator in a pure TRV situation?I would have hoped you got that one right Chris!!!! E-mail me your size and address and we'll hook you up...
@ February 18, 2013 9:41 AM in How would you control a Bumblebee circulator in a pure TRV situation?Have had a BumbleBee of various generations in my house for 3 winters now - with outdoor reset, panel rads and TRV's -- hasn't happened yet. System doesn't deliver much heat in November because not very much is needed. Nor has it happened in any of the test sites used during the 3-year development of the Bumblebee, nor have we seen it happen in any of the installation since its release.
@ February 17, 2013 10:35 PM in How would you control a Bumblebee circulator in a pure TRV situation?Hi gang --
This is sorta what I have in the lower level of my house. Panel rads with TRV's and a Bumblebee - with a minor variation. The panel rad in the family room -- largest load by far - has no TRV - that room runs off a thermostat. All the panel rads are piped with dedicated supply and return PEX runs off a valved manifold. There's retrofit radiant floor in my office - runs off the same manifold as the panel rads - and it operates off the family room thermostat as well.
The thing to remember about TRV's is that they modulate - they're usually either opening or closing- regulating flow through the radiator. This control method lends itself to "continuous circulation," primarily for electrical simplicity more than anything else. This application is pretty standard in Europe, and is what Delta-P circulators are designed for.
Would a Delta-T Bumblebee work in this situation? Well, why wouldn't it?
Let's say you decided to run it "continuously" (which kinda defeats to the purpose of "electrical efficiency," the most efficient circulator is the one that's off - but that's a different story for a different day). You program the BumbleBee for the Delta-T you want (20, 30, 40 - whatever you designed the system for), and then put the supply sensor on the supply piping, and the return sensor on the return piping - near the return side of the manifold and the turn it on.
The pump runs to establish the Delta-T you've programmed. With all the TRV's fully open - you're pulling a lot of BTU's out of the fluid. The return water temperature may be fairly low -- and the circulator will go faster. As TRV's close, or modulate towards closed, that means the radiators - and the system - need less flow. The return water temperature would start to increase - and the Bumblebee will slow down.
So what happens when it's warm out and you don't need much heat at the radiators? Well, if you have outdoor reset on the boiler, everything chugs along as it would if it were colder out - with one exception. The BumbleBee will run at even lower speeds when it's warmer out - like in late November - than when it's colder out, like in mid-January - and there's a Taco T-shirt in it for the first person who knows why!
If there's no outdoor reset, the TRV's won't open as much - to regulate flow through the radiator. Again, since there's not a lot of BTU's being taken out of the fluid, the Bumblebee will react accordingly. Will the pump dead-head if all the TRV's are closed? Yep - so will a Delta-P pump. Don't forget those things are always running, and the impeller is always turning - even when there's no flow required.
What will the Delta-T function do if all the TRV's are closed? That's a pretty rare occurrence, because TRV's aren't made to be "off," they're made to modulate - so the likelihood may be completely off the radar, but just suppose...
Let's say it's mild out - and reset says the supply water temperature needs to be 120, and you've set the Delta-T to 30 degrees. That would mean the pump would run at a certain speed in order to bring the return water back at 90 degrees. As TRV's close - as in completely closed - the BumbleBee will slow down accordingly. When the last TRV's closes completely, the pump will be running very slowly. Now there's no flow. The pump will run at that same speed until the it senses that return water temperature dropping. It's not moving, after all, so it will probably drop some. The pump will try to get that return temp back up by ramping up -- slowly. Once one of the TRV's opens up again - the sensors will get a reading of return water temp changes, and the pump will do what it needs to do.
Again, this is one of those occurrences that is mostly theoretical - and if it does happen, the time period is wicked short.
How would a Delta-P circulator handle this same situation? Look at a Delta P pump curve chart. Delta-P pumps work on a fixed pump curve -- they're funny looking pump curves, but they're fixed. Even the Alpha - it has a range where it operates, and changes are based on pre-programmed algorithms - but it's still a pump curve. If all of the TRV's are closed, the Delta-P pump will work at the spot where the low end of the pump curve intersects the 0 GPM line - it's a fair bet the BumbleBee would be running at a lower speed because the pump adjusts to what the system needs, with a constantly-adjusting pump curve. Check the Delta-P curves to see where that intersection point is.
The other thing to remember, a Delta-P pump runs the same speed in January as it does in November.
There's lots to digest here, but at the very least you guys helped me write a new blog post! I don't check here very often, but if you have any questions, please email me directly at email@example.com
@ July 31, 2012 7:47 PM in Hydronics Roundtable EventThis is going to be one hot event! Looking forward to seeing everyone there and being able to listen to some great speakers! Honored to be able to share the stage with some of the best in the business!
My program will be "How to Estimate Fuel and Electrical Usage in Hydronic Systems." It's a little more in depth than "use the force..."
If you haven't signed up, do it today! It's gonna be an EVENT!!!!
@ January 27, 2012 12:28 PM in Happy Birthday Dan HolohanYou have skills, my friend. All the best!
@ January 25, 2012 11:46 AM in Congratulations John Barba...Thanks for the kind words, gang. Really am speechless! I'm very honored to be entrusted with this amazing artifact - named after two giants - and look forward to telling its story for the next two years.
Just hope I don't break it!
@ July 24, 2011 12:23 PM in John BarbaThanks for the birthday wishes! I was shaken this morning to realize that 51 is only 9 years away from 60....
@ July 4, 2011 10:15 AM in Terrible newsUnbelievable when violence hits home like this...its a struggle to find the words....
@ June 17, 2011 5:34 PM in Taco Training this weekPleasure having you there MikeyB! You helped make it a fun program!!!
@ March 25, 2011 8:52 AM in Some good training here!Looking forward to seeing you there!
@ March 25, 2011 7:34 AM in Some good training here!He's one of the best --- highly recommended!
@ February 23, 2011 6:12 PM in B&G Little Red Schoolhouse instructorHe was one of the best. Went through the Little Red School house in 96 or 97 - learned more than I could have ever imagined - I'll remember Bob ringing the school bell when it was time to come back from break.