Hydronic retrofit - circ pump and low loss header sizing

moosepucky

Is this the type of pump you were taking about earlier?

https://us.grundfos.com/products/find-product/alpha.html

tbrooks

T, I don't quite get the general logic on this, won't the emitter be hot if the flow is higher than necessary? The convection process doesn't know how fast the water flow is, it just does its thing naturally. Gary

I'm no expert, just learning things myself. Just makes perfect sense to me, thanks @Rich for a better explanation.

moosepucky

I was wandering around the basement (aimlessly thinking about the boiler layout) and happened to notice my TMD-56 still attached to my coffee roaster. I've used it so long in that dedicated process that it never occurred to me that I could hook up a couple k type flat probes and wire them to the suppy/return feeds.

Man oh man the basement lit up when the light bulb went off...

SWEI

Nice rig. Are you playing with PLCs on it?

moosepucky

That was an old photo before I added the 2nd probe but shows the meter...

Now I have 2 k-type probes BT and ET (Bean mass temp and roasting chamber temp).

Meter feeds directly out via USB to a laptop running dedicated coffee roasting software

Coffee has gone well beyond a hobby to an obsession with me (obviously).

Link to a pic of my current "coffee wall" in the kitchen:

http://i1066.photobucket.com/albums/u414/turtle-web/food/coffee/11-16-2015_coffee-wall2_zpsscfpmvcw.jpg

A more recent photo of the roaster below.

Hope I have not hijacked my own thread

Gordy

I have no words, and I love my coffee.

tbrooks

I don't drink coffee... all I can say is wow. Never new such things existed

SWEI

Taiwanese high mountain oolong here, but I do appreciate the odd God Shot.

Gordy

Uh oh there's the God Shot term. It seems the coffee geeks can be quite anal attentive also., and yet except some of the unexplained.

http://coffeegeek.com/opinions/coffeeatthemoment/11-12-2002

4Johnpipe

@moosepucky The "racetrack" you have is basically a gigantic supply and return manifold. We use the new manifold with home run method because it is less expensive to install a supply and return manifold near the boiler than to run 1-1/2" pipe all the way around the basement. Secondly we can control the flow precisely to each radiator with flow controls on the manifold. Your system with mono flow T's leaves a lot up to nature / physics to due what we now can do. You say you have flow valves at each radiator so you can adjust them as needed to achieve you comfort level.
The only sketch I saw that was no good is the one with a single mono flow T in between 2 mono flow T's. You will need to avoid that scenario.

Paul48

I hate to be the "dark cloud", but balancing a monoflo system with valves will prove near impossible. It, also, has a similar effect to throttling your circ, and will drive the head up rapidly. Manifold would be a poor comparison to your system. It's a "horse of a different color".

Gordy

It mimics a parallel piping concept. What goes in a t must come out of a t.

ratio

Interesting method. Have you done this before? It seems like it is very depended on the emitters being properly sized.

Paul48

I think the reason he has 1.5" main loop is because the system pumps about 25+ gpm. The 2218 will do 15 or so, and less once you start balancing it. That takes it below the capabilities of a 007. I don't know....

jonny88

You mentioned the Alpha a few times,don't get stuck on it the numbers it reads out are not 100%accurate as I have witnessed in my own house.Hot Rod said it to the other day that their numbers can be way off,very disappointing.

moosepucky

@4Johnpipe

You are correct, my sketch was not accurate. On the feeds with 1st and the 2nd floor together, the 2 center of the 4 are close T and feed the 2nd floor. The main floor feeds are #1 and #4. I drew it from memory and should have looked.

Valves at convectors:

Below is a pic of the valves that are on each of the the feed sat the convectors. I cannot locate anything that looks like this and wonder if they were sourced from the convector manufacturer when the system originally was installed in 1950.

They appear to have a screw with lock nut.

Paul48

Those are balancing valves. The slot reflects the position of the butterfly.

GW

Moose, use some caution when you start sticking tools on those old valves. Life has very few guarantees you know. You should just run it the way it is, see if you have cool rooms, etc.

Gordy

Yeah unless, someone tampered with them. The original install would have balanced them initially.

moosepucky

The balancing on the original 65 year old system seems to be 100% spot on.

I have not taken my dual channel data logger into each room (yet) but for the 25 years that I have lived here, I have never had any reason to complain. To me, all rooms are the same temp. I have no idea how small of a change the human body can detect (I do know that the human ear can detect a 3db change) but this old/original system must below what ever threshold the body can detect.

Now that I know now to measure Delta T (difference between in and out temp taken at the source) I will be having some fun charting the entire system.

I do have a serious question though.......

The Bosch combi boiler has an internal 3 speed pump on the SUPPLY side which runs 2/4/8 gpm (spec sheet from manual below). It also has an internal expansion tank (another question for later).

OK here comes the question.......

Can I run the "loop" from boiler to LLH and back to the boiler using the Bosch internal supply side pump, AND run the larger race track with the Alpha pump I purchased in the return loop on the other side of the LLH?

GW

Yes the internal pump to one side of the LLH and the Alpha on the other side of the LLH.

Make sure you can purge the air out of the boiler though.

4Johnpipe

Yes the LLH is hydraulic separation the 2 pumps do not see each other...

4Johnpipe

I am relatively sure the Bosch allows you to use the boiler pump to purge the air in the control board.

SWEI

moosepucky said:

I have no idea how small of a change the human body can detect (I do know that the human ear can detect a 3db change) but this old/original system must below what ever threshold the body can detect.

ISTR that number being something like half a degree Fahrenheit. One is obvious to most.

Gordy

my wife is .25 degrees

Abracadabra

Gordy said:

my wife is .25 degrees

bmwpowere36m3

Hatterasguy said:

moosepucky said:

race track with the Alpha pump I purchased

The Alpha is the wrong pump for your system.

You have a single zone. The Alpha varies speed based upon changes in headloss. Your headloss is constant. Therefore, effectively, the Alpha is a single speed pump.

Return the Alpha and purchase the Taco VT 2218 which will vary the flow rate to maintain a specific ΔT. In your system, you can set the ΔT to 30°F and enjoy significantly reduced return water temperatures (thereby ensuring condensing for most of the season).

The Alpha cannot do this.

The Alpha pump is capable of three constant speeds, three constant pressure settings and an Automatic setting (it supposed to be "smart" and learn, not sure the specifics of operation)…. so seven different modes of operation.

That's where I'll leave it… since I'm not experienced enough to provide more insight.

Gordy

Shhhh. Secret.

SWEI

Gordy said:

my wife is .25 degrees

Mine too...

GW

Now I'm extra curious. If the alpha doesn't work I'll buy it from you and pay you to ship it to me. Like new condition that is.

moosepucky

@GW It has not arrived yet. Won't be here until next week sometime.

moosepucky

the Bosch boiler has an internal expansion tank.

I was planning on re-using the existing atmospheric expansion tank

Not sure where to place it.

Inside the LLH (boiler side).

Outside the LLH (monoflo side)

I would think that the internal expansion tank would handle the boiler needs inside the short loop to the LLH and that a second tank should be on the monoflo side.

should I use a modern air/bladder type expansion tank

The old tank is 12" diameter and 36" long

GW

These old systems always get an 007 or an 15-58 pump when the original 3-piece bites the dust, I'd love to see how the alpha does. Also, i would be inclined to leave the internal pump setting alone.

GW

your choice, we never keep the old tank, yet it certainly will do the job. We want a clean new install, and nothing that confuses what our warranty covers and what it does not. But if this is your own home, have at it.

Bob Bona_4

If the boiler has automatic air vents/air scoop/microbubble resorber, and it should, you must use a bladder tank.

moosepucky

The boiler has an internal bladder type expansion tank.

I should have another expansion tank on the monoflo side also, shouldn't I?

GW

Like everything else, you'll probably get two answers, but most people would indeed get another tank on the system.

Gordy

@GW there are two angles going on here. One is yours using the alpha the delta is what it is. The other is using variable speed delta t, and a whole lot of tweaking valves to get balance, and maintain a set delta through all loads.

Gordy

Agreed to an extent. Much harder to dial in a set DT through all loads throttling than throttling for comfort.

Gordy

That has merit!