Overpumping emitters.

@Harvey Ramer
Running a gravity conversion at a 12*DT would come nowhere near replicating the conditions that existed during gravity circulation. Which is what everyone claims to be trying to do. No one would ever suggest balancing a manifold system by increasing pump capacity. The mains in a gravity conversion are nothing more than high-mass manifolds. I understand that not all customers want to go to the time or expense of doing the job correctly. And, this provides an alternate way to get heat to all the radiators. But, it really needs to be framed, and presented, as such.

Again, this is my unprofessional, common sense opinion, based on information learned from ALL the folks here, and on my own.

You mean to tell me, in a properly designed hot water system, the radiators get bigger and bigger as you go down the line?

Weird.

Gordy said:

ChrisJ said:

You mean to tell me, in a properly designed hot water system, the radiators get bigger and bigger as you go down the line?

Weird.

No that's not it.

How do they cope with the cooler water down the line then?

Gordy said:

Okay let's do this Hat, and Steamhead.

1491 SF. EDR. Gravity system.

Let's put some substance to this.

Both of you come up with your circ of choice, and then compare. Electrical consumption differences, and differences in the deltas the system would see with the circs you choose.

Boiler is a CI variety piped with low return water protection.

If you want size a circ for a direct piped mod/con also.

Heat loss is 100k

Hmmmm. 1491 square feet of old gravity-piped cast-iron radiation and a heat loss of only 100k at design? That's some serious over-radiation. That amount of radiation can give off 223,650 BTUH at 180°F and the long-standard 20° ΔT. Did they intend to heat the whole house with the windows open? Or maybe the owner had a deep energy retrofit done that cut the heat loss in half? But OK, we'll go with it.

For this example, I will assume that the owner does not want to replace any radiator valves and most of the existing ones are stuck wide open. This is a common scenario in the Baltimore area, though some will go for TRVs in bedrooms and other areas that they want to keep cooler than the main living areas. To circulate this system at or near the rate it would have circulated with the original gravity boiler at full fire, we will need about 36 GPM at a 3-1/2' head. Closely matched to this figure are the B&G PL-36, Grundfos Magna-3 32-60 or UPS-32-40 or Taco 0013. The Magna is, I believe, the only ECM unit mentioned here but I'm sure there will be others- Taco just came out with their 007-e but that's too small for this application.

The 007-e would, however, be the right size for pumping the boiler. 10 GPM at 3-1/2' of head is roughly in the middle of its range. If using a standard circ, maybe a Grundfos UP-15-42 or 15-58. Another interesting option might be one of Taco's 00-VR circs (go here: http://www.taco-hvac.com/uploads/FileLibrary/CAT100-024varspeedoocirc.pdf) which change their speeds using outdoor reset, to vary how much boiler water needs to be injected into the system. I would not use the Taco 006 in this application unless it were available with standard mounting flanges, which AFAIK it is not.

This job would require some way to decouple the boiler from the system. Not having actually seen the job, I'll just say that either a primary-secondary setup or some sort of hydraulic separator could be considered. The I-valve is a nice concept, but it's easier to replace a circulator than a mixing valve if something goes wrong. It's important to be able to get the heat on quickly on a 5° night.

Power consumption would, of course, vary according to what circs we used. I won't go into all the possible variations and permutations yet, let's narrow it down first.

Hatterasguy said:

Harvey Ramer said:

Can I add a rule Gordy?
Good.

The homeowner doesn't have the extra money to pay for individual riser balancing devices or TRV's (the latter being the better cheaper option by the way). Or even if they have the money, they aren't going for it.

And the system is old as dirt, which most of them are.

The reason I suggest this rule is more times than not this is the reality we deal with daily.

With the institution of your "rule" obviously Frank's system wins.

The H/O gets a wildly overpumped system with massive room overheating at the elevated boiler SWT (constant for the entire season).

The problem is this is reality.
Just like some of us have 150+ year old houses that leak air like a sieve and need a massive amount of heat added to maintain temperature. Or for that matter, cooling in the summer.

There's no money to fix the problem and even if there was it would likely never pay off anyway, comfort aside of course.

People need to do the best they can with what they have to work with.

@ChrisJ - Agreed. It's called the real world.

I don't fit the description of the individual Harvey mentioned, but if it was me I'd want to know what I did wrong so I wouldn't do it again. #learningopportunity

Paul48 said:

Harvey's obviously being coached by Donald Trump.

Woah.
Them's fighting words.

Stephen Minnich said:

Thanks @Stephen Minnich ! Don't you care how much beer can sting when it comes out your nose? At least I turned my head far enough to miss the laptop. Hahaha

I will take full responsibility for stirring the pot though not intentional. My hope was to find a common understanding of each other's perceptions, and theories. I posted this several posts back. It is still how I feel about the methodology of it.

Gordy said:

I fully understand both sides of the argument. The question becomes how much time does a contractor spend to get it perfect. Perfect is Hats perspective. Nothing wrong with that, and I'm quite sure with enough devoted time it would work. That time involved is greatly dependent on how the potential systems condition is.

Time is money. when it comes to the three bid owner that needs the work done who will they choose? Obviously perfect is more involved than better than what was there so that bid will be higher. If better than what was there makes the owner a happy customer compared to what they had I get that. If you get the job, and can talk them into perfect so be it.

Frank put some time, and effort into a theory that does work, and has some substance that can be applied with out much effort with an edr survey. It's not perfect, but it does give results that are most likley better than what they had.

The savings of perfect is not a heck of a lot unless you can drop to an ECM circ. Most likley in a constant pressure mode setting with constant circulation as Kurt has done. In his example savings were quite measurable. With a drop from say a b&g series 100 HV to a taco 007 in a bang bang set up not so much. In the end the owner has heat to all rads. They saved on electric due to the smaller pump that is still over pumping compared to perfection.

Now if we are strapping a mod/con to the system then Hats stand point has even more substance to get the con out of the mod. But with ci boiler not so much..

I can tell you that you can narrow a system delta by changing circs, and still save watts. I did it on my own system. Changing from a series 100 HV to a pl30 wet rotar increased my flow rate, and saved about 50 watts in power consumption. System delta narrowed from 15 to 13. Radiant side.

My heart be still!

GAS? Dude - show some respect for Erin, will ya?

HEY! SHOW ERIN SOME RESPECT BOYS. ENOUGH IS ENOUGH. MAD DOG

It's too bad there isn't some type of "arbitration" to settle differences. Well.......It's better than walking ten paces, turning and firing.

Understood. I've just never known Steamhead to be anything but super helpful, calm, level headed and just plain nice. Just backing up a good man. All good. Everyone have a great weekend. Mad Dog