NEED HELP WITH FLOW MIXING OF CALEFFI SEP AT MY CASTLE

jackrich99

Hello I am in need of some help with flow mixing. I bought a castle a couple years ago am in the process of figuring out the existing radiant heat which I did not install. Had many issues such as leaks ect... Right now I just installed a Laars Neotherm 80K for now. As of right now it's supplying 2 zones of 5\8 Wirsbo hepex in the slab about halfway in the middle of a 5 inch poor. The first zone is 38 by 15. It has 3 loops of about 300 to 350 feet of 5\8 tubing. I used Watts Radiant pro software and the heat loss says 15,454 btu of heat loss. This sounds extremely high since the zone consist of a kitchen and a small living room with 3 windows that are 3 by 5 and a door leading to unheated garage. The castle was built in 1998. The 2nd zone is a little harder for determining heatloss because it has 2 floors all being open with a 30 ft ceiling with basically a hole in the roof leading to the 3rd floor of the castle. (Not really a hole but its open to the 3rd floor via spiral stair case which is all enclosed heated space)I will post pics of house and system. The zone measures 38 by 30 with a 30 foot ceiling. Only heat in this zone is the first floor radiant of 3 loops of about 300 feet of 5\8 wirsbo hepex. The heat loss for this zone is around 25,00 but. Right now If I have the boiler cranked up to 180degree Fahrenheit when it gets to the radiant manifold 25 feet of 1 inch copper away the temp is 125F. The return piping is 25 feet back to boiler. I used Siggy's software and the Total Equilavent Length of piping is equalivent to 153ft of 1 inch copper. Right now I have 2 Taco 008 pumping IN to the boiler and a B&G NRF 22 pump on the supply side of boiler and another NRF 22 pump above the manifold supplying the radiant floor. I have too much mixing going on I believe in the 1 inch Caleffi hydro sep. I am guessing that there is not enough going into the floor and backing up to the boiler. My question is what can I do to balance this for now as its cold outside and I just have some heat to keep wife and kids warm. Please keep in mind I am not finished with the system as I still have 3 more Laars mod con boilers that are 130k btu to hook up if necessary when I get the rest of the house hooked up. Once again thank you in advance for reading my post as I tried to keep as short as possible with all info needed when asking for help.

unclejohn

I would switch the red pump the air separator first on the system side. Then move the taco pump to the supply. Here is a link for piping.
http://www.caleffi.com/sites/default/files/file/01076_na.pdf

Zman

What you have is pretty unconventional. Could you draw a sketch with rough distances so it is easier to follow?

jackrich99

Yes I will do it now.

Zman

I see one 008 pumping into the boiler, is there another one? How is it piped?
One red (NRF-22?) between the hydro seperator and air eliminator. Is the arrow pointed left?
What is the circ in the other picture by the manifolds?
Can we talk about the wiring (later )?

jackrich99

Right now their are 6 loops feeding these 2 zones and 4 out of the 6 are on right now. The remaining 2 loops have a leak which I already found this morning and getting ready to break out the Jack Hammer. Doesn't everybody wives love jack hammering up the kitchen and living room. Lol Attached are some pics from 2nd floor looking down at the front door. The house is only about 80 percent complete. That is the mess you see. This is the zone I am trying to heat. Their is currently no heat emitters of any kind on the 2nd floor, although previous owner did run 3\4 pex in a home run distribution for 6 hook ups on the 2nd floor.

Zman

When you run the math on this, 1-008 is plenty for the boiler side and 1-NRF-22 works for the radiant side. I am wondering if the piping is incorrect. Putting the other circ and direction of flow on the drawing would help.
Another good trouble shooting aid is measuring the supply and return temp on the boiler and the supply and return temp on the radiant side.Also, what percentage of output does the boiler indicate.
You definitely don't need more crculators and I would be surprised if you need more boiler.

jackrich99

The drawings are the same I thought maybe one is a a little clearer. Using Siggys software the supply\return header is equavilvent to 150 ft of 1 inch copper. When I disconnect one of the 008 I still have flow at the manifold just not very hot. Boiler set to 180f and temp gage on manifold says 120 max. That is after its been running for an hour. Boiler modulates between 60 and 100 most of the time. I didn't hook up the outdoor reset yet. Hope this sketch is better. Thanks for your time.

jackrich99

My concern at the beginning of the post was that boiler is cranked up to 180F and when it gets to the manifold 25 ft away the highest temp I can get on the manifold temp gage is 120F. What are the opinions on having the temp gage on the return side on the supply side of the hydtro sep just before the first Taco 008. That a soldered temp gage and it takes up at least .25 inch inside the 1 inch main return headed. Essentially the return header is reduced from 1 inch to 3\4 right before going into the boiler on the inlet side. Right? Would you remove it? Put somewhere else or do away with? I see those temp gages on install a lot. Thanks

Zman

Is the boiler actually producing 180?
With slab radiant, 180 is undesirable and often unobtainable due to this inconvenient thermal equilibrium thing.
I sent you a message earlier.

hot_rod

There is usually some blending of temperature going on inside hydro separators. Here is the math that helps determine what the blended temperature is under various flow rates

Google idronics 1 and download the pdf

Zman

Jack,
After a bit of thought, I think I have some answers as to what is going on in your system.
It comes down to one of the key rules of hydronic design. You should always pump away from the "Point of no pressure change" AKA the expansion tank.
In your system one of the NRF-22's is pumping into the expansion tank, the other is pumping away.
This might not seem like a big deal until you consider that the NRF-22 pumping into the tank is interrupting the 2-008's ability to pump away from the expansion tank. This is wreaking havoc on the pressures in the hydrolic separator and causing it to do some very undesirable things.
Try turning off the power to the NRF-22 between the separator and the expansion tank and see if things improve.
Carl

jackrich99

I forgot putting that pump right there is pumping into the expansion tank. Mr. Holahan and a couple others have done a real good job explaining the pumping away from no pressure change. I will unplug now and post results of changes after 60 minutes. Speaking of expansion tank it's a 3 gallon was is currently oversized with 6- 300 ft loops of 5/8 helped and 50 ft of 1 inch header piping.

jackrich99

Update using Siggy software total system volume is approximately 37.3 gallons thus making expansion tank almost the right size. Software calls for 2.9 gallons tank at 180F max water temp, 60F temp of water when filled and 9.3 psi charge on tank. Thanks Zman for noticing I was pumping into PONPC. I guess that's why the pro's flip over a bucket and sit and look for awhile.

jackrich99

Zman to answer your earlier question the boiler outlet temp is 182F at the boiler, 180F at the gauge on the hydro sep supply side. (There's only one gage on hydro step) and the boiler temp is 168F at the boiler inlet sensor with a 13F Delta T across boiler heat exchanger modulating at fairly constant 70% rate. Thanks for your time.

jackrich99

Also wanted to add 25 ft of 1 inch header supply piping the temp on manifold gage supply side is 125F returning at 110F this giving a Delta T of 15F thru the radiant floor. Thanks for your time for reading

CMadatMe

Well let's see what the math says.

Boiler Pump moving 10GPM (based on install manual 008)
System Pump when everything open - taking 8.2 based on posted heat loss, radiant design for 10 degree delta-t

This equals impossible to have a temp drop across the LLH. Only time you can ever have a temp drop across the LLH is when the system side flow rate exceeds the boiler side.

I will say the exp tank and feed are on the wrong side of the LLH. Anytime you use a LLH exp tank and feed should be on the boiler/primary side below the pump (ie pumping away). Reason being is velocity slows in a LLH and that's where you have the most chance of air coming out of solution. Keeping feed pressure on the boiler side w/exp tank protects the HX from flashing in case of that air coming out of solution.

Zman

Chris said:

Well let's see what the math says.

Boiler Pump moving 10GPM (based on install manual 008)
System Pump when everything open - taking 8.2 based on posted heat loss, radiant design for 10 degree delta-t

This equals impossible to have a temp drop across the LLH. Only time you can ever have a temp drop across the LLH is when the system side flow rate exceeds the boiler side.

I will say the exp tank and feed are on the wrong side of the LLH. Anytime you use a LLH exp tank and feed should be on the boiler/primary side below the pump (ie pumping away). Reason being is velocity slows in a LLH and that's where you have the most chance of air coming out of solution. Keeping feed pressure on the boiler side w/exp tank protects the HX from flashing in case of that air coming out of solution.

@Chris,
Picture a scenario where each circ is producing about 3 psi of differential.

If the PONPC is charged to 15 psi, The other circ in that series will be make the supply manifold 18 psi.
The pressure at the separator because of the first circ pumping into the tank will be about 12 psi.

Now on the boiler side, There are two Taco 008's (in series). I suspect that the 6 psi they generate will work against the first circ that is standing between them and the PONPC. I am thinking that this is causing some unpredictable mixing, most likely in the chunk of pipe between the separator and expansion tank.

This would explain the "impossible" conditions that exist.

What do you think?

Carl

CMadatMe

2 Pumps? Didn't even catch that but the only negative effect on the boiler side since we are hydraulically separated is greater flow to the LLH which still would be larger then the system side flow rate. If anything you'd have elevated boiler temps due to exceeding max flow rate across the HX which would give a false temp reading for boiler side supply temp shutting the boiler on high limit. Boiler holds nothing for water.

Basically the LLH is never seeing what he thinks is 180 degree water. Why the 2 008s in the 1st place? Get rid of one.

Zman

There are definitely 2 to many circs in the system. One on each side.
Idronics 16 around page 36. Shows the subtraction pressure when you pump into the PONPC. I believe the "separation" is being compromised by this.
I agree with your earlier statement that the supply's should be the same temp with hydraulic separation. The fact of the matter is that they are not the same. This led me to this theory.
Thanks for your input.
It will be interesting to see how this shapes up.

jackrich99

Thanks for your comments. To update I unplugged the NRF 22 circ thats right after the LLH and before the air separator and their was no difference in anything, the flow and temps thrust manifolds exactly the same. Now I will disco one of the 008 and see what happens. I agree with you guys that the supply flow is more than the load can handle right now. Only 6 loops outta 12 loops total working now.

To answer your question Chris the reason for the 2- 008 is when I first installed this a couple days or so ago I put a check valve on the supply side after the air step and before the manifolds and couldn't even get warm water to flow to manifolds. First instinct was need more pump, and I had it sitting around. Wrong! Removed the check valve and she was flowing
.

jackrich99

Typo- flow and temps thru manifolds exactly the same

CMadatMe

You are piped primary/secondary. You could put a pump the size of your castle and it's doesn't matter. If the Neo has the built in pump get rid of the added boiler pump. Get the boiler side fixed first. It's the 1st chapter of the book. Have to remember you have 3 systems here. Boiler sides only job is to move the flow/water temp (btu/hr) to the LLH. It's job is done. Then system pumps move flow/water temp (btu/hr) throughout the system. Then the emitter (floor) moves the kiddies off the train.

The boiler pumps have zero influence on the PONPC as its piped in the pics.

jackrich99

Thanks for the info Chris and Zman. Got 2 circa hooked up now instead of 4 and accomplishing the same. Do you have any suggestions on how to LESSEN the flow on the boiler side to better closely match the supply side. I have 7 loops working outta 12 so far. I didn't wanna buy a balancing valve because not sure what I will have when I am done. Other 5 loops aren't holding pressure yet. What about closing ball valves a little to slow flow for now? If so which ball valves supply side to manifolds or pumping into boiler before or after the circ? Thanks

Zman

There is no need for the flows to match.That is the point of the separator. Your boiler does need a minimum flow rate due to it's design.
Do you have the actual supply and return temps for the boiler supply and return and the manifold supply and return?
Be sure you are looking at actual temps rather than the setpoint or target.

jackrich99

There is the inlet and outlet temperature measured by the boiler by way of sensors inside of the boiler jacket. The supply/return manifold has temp gages. The boiler inlet sensor reads temp reads 136F and the outlet temperature reads 162F. The boiler set at 160F with a 10degree hysterias or differential. The temp gage on manifold supply reads 110F and returning at 92F. In my mind I am losing 50F temp difference from the time it leaves a boiler and arrives at manifold 25ft away. Thanks for your time Zman.

Zman

How comfortable are you with the gauges? What you are reporting should be impossible. Do you have a way to double check the temps?
Is the house heating?

jackrich99

Very comfortable because I confirmed it with a thermal imager. The gages are sensors on the boiler. The gates on the Caleffi hydro Sep seems to be accurate as does the temp gage on the return piping just before the hydro Sep which I believe that gage needs to be on the boiler side to do any good. Early on in this thread Hot Rod posted link for algebra equation to figure out the flow mixing. Algebra makes my head hurt but not as much as this does now. (This being "paying to heat water to 180F when only 110F water is of any use) Going to get my archive of Idronics, which any contractors reading this and don't already receive your FREE copy of Idronics go to Caleffi and be put on mailing list.

jackrich99

Yes the house is heating but it's about 10F out at 8am and a lot of cold air seeping in from doors and fireplace. Called all the windows yesterday. So I can't blame the heating system for a drafty house. Gonna weather strip door today.

CMadatMe

I have an excel spreadsheet I made that will do all the math for you. See attached. Save you the headache of the math

jackrich99

TYPO-Caulked all the windows.

Mark Eatherton

Chris said:

I have an excel spreadsheet I made that will do all the math for you. See attached. Save you the headache of the math

Hey Chris, mind if I share that Excel spread sheet with the RPA members? Cool tool. Thanks for sharing.

ME

CMadatMe

Mark Eatherton said:

Chris said:

I have an excel spreadsheet I made that will do all the math for you. See attached. Save you the headache of the math

Hey Chris, mind if I share that Excel spread sheet with the RPA members? Cool tool. Thanks for sharing.

ME

Don't mind at all Mark. Here's another one I made. Just makes things easier some times. Been looking for an App that has this one plus the other all in one nice place but haven't found one yet.

Mark Eatherton

Thank you!

To whom should I give credit to for the development?

We have a place on the RPA web site for "members only" and I will be sharing these and others that I have developed with the RPA members.

We appreciate it.

ME

Zman

Chris,
Thanks for the share. I was doing the math the long way a few days ago your sheet sure makes it easy.

Back to the original post, Does anyone have thoughts on why this guys system will not match those numbers?

CMadatMe

Your welcome Zman. I think at this point pictures are required. Its no more then a guessing game without them.

Not looking for any credit Mark. If they help someone that's all that matters. Thanks for asking though.

jackrich99

I will post pics as of today. I now have 8 loops of about 300 to 350 ft of 5\8 hepex balancing valves wide open and all 8 loops are flowing almost 1gpm and boiler still set at 180F water temp and now the hottest water temp I can get at the supply manifold temp gage is 85F and returning at 75F. 20F outside temp in zanesville ohio and windy right now and about 60F inside. I think one problem is this temp gage on return side just before the hydro sep. Its a soldered temp gage that takes up a quarter inch inside pipe basically reducing from 1 inch to 3\4. Will attach pics.

jackrich99

First 3 pics of boiler room and last pics is of manifold station 25 ft away. As a refresher total equavilvent length of header piping with all fittings 150ft of 1 inch type L copper and 2 total circa. One Taco 008 pumping into Neotherm 80K and 1 NRF 22 right above supply manifold. The NRF 22 on supply side right after LL header isn't plugged in. Hadn't had time to remove it. Maybe to keep things a little less confusing I will leave load or heat loss calcs out of this because not all 12 loops are working yet and loops in floor may not even cover the load in 1 zone so I just combined them all for now. House is very open anyways with very little thermal break between rooms. (If that's right word I am looking for "thermal break". Attached is a pic looking down from 2nd floor right inside front door. Thanks for your time.

CMadatMe

Ever check to see if that air separator is clogged up or adding restriction the pump can't or is having a hard time over coming?

jackrich99

No never thought ABOUT that since its new, but being new is why I should check. Great ideal. I did remove that temp gage on return side before hydro Sep and can now get temps of 112F on supply manifold and returning at 100F. 12F Delta T. It's 15F outside and 65F inside.

Tom_133

jackrich99

Sorry if this has been mentioned, what are you getting for flow on your manifolds? I noticed in the pic what type of manifolds and sometimes the supply or the return are not open all the way, or enough. Of course you will end up balancing and setting your flows before you are finished, but wasn't sure if you had that done that yet. This would lead to your lack of flow. Just a thought