Primary/Secondary looping for multi-temperatures

PipeJr

Gordy said:

The top loop may be getting robbed if both loops are operating at the same time. Have you tried just the top loop?

@Gordy I have tried just the top manifold by itself no luck; as @Paul48 posted I'm not entirely sure having them separate would make a difference. I was tempting to save on piping and combined both return manifolds together.

Paul48

How have you determined that the top loop is not getting the temps you want? What are the temps?

PipeJr

Post 4 way is 125-130 ; manifold gauge showing 90. even after removing air and properly aligning circ. When I first tried lower manifold circ. it took a few minutes until it got flow moving then really was noticeable. Waited a few minutes for top manifold circ. but didn't repeat what I noticed the lower manifold circ. do. I even turned off all loops in return other than top manifold loops. Should I just wait longer for the circulation to occur? Don't want to burn up a perfectly good/new pump.

PipeJr

Top manifold (2loops) must immediately travel up 12 feet. before running horizontal in joist bays.

PipeJr

Gordy said:

Yeah ditch that. I was looking at the high temp loop.

@Gordy I will take your advice on the Boiler loop creating T's and push instead of pull circ.

Does anyone have any better suggestions on the low temp Secondary setup?

Paul48

You didn't get all the air out.

Paul48

Height has no bearing in a closed system. There's just as much pipe coming down as there is going up.

PipeJr

When I do properly T off my boiler (high temp) loop I will put the lower (larger) manifold as the priority zone so as not to impede the upper (smaller) manifold circ.

Does that sound ok? or again is there a better piping idea for the low temp Secondary loop?

PipeJr

Paul48 said:

I theorize that they are pumping against each other. The larger circ is creating so much head in the return manifold it's stifling the smaller circ. Try running the smaller by itself and see if you get a different response.

@Paul48 Do you suggest that I should try this configuration for the Secondary loop return?

Gordy

Uhmm looking at your heat loss. Almost 100k on those two manifolds together........what size pipe is feeding those manifolds?

At 2-4 FPS
1/2" 15k
3/4" 45k
1" 72k
1 1/4" 125k


Highest head loop is 12.1' on two loop manifold, and 11.8' on 6 loop manifold. Plot those heads on the corresponding circulator curve. That's your gpm to those manifolds. Highest head loop.



I'm only trying to help. I assumed your emitter is radiant seeing as you are mixing down.

Gordy

It's early but those loads are atrocious unless you live in the arctic circle.....certainly not doable with radiant.

hot_rod

Here is a good options to solve all the problems. Hydraulic separation, dirt, air, magnetic all in one, simple, clean and it works.

Paul48

@PipeJr
Did you account for the additional head created by the 4-way?

Gordy

hot rod said:

Here is a good options to solve all the problems. Hydraulic separation, dirt, air, magnetic all in one, simple, clean and it works.

I think we need to start at the beginning here..........heat load.

Gordy

Heat loss Bumped

PipeJr

@Paul48 - Pumps and 4 way configuration (Secondary loop) determined by Taco design engineer.

Paul48 said:

Forget the loop around the low temp loops. It won't work.

- wouldn't having a loop around the low temp loops using T's for each circ. hydraulically separate these two zones?

@hot rod - so your saying I have to use (2) expensive 4-way mixing valves?

PipeJr

Paul48 said:

I theorize that they are pumping against each other. The larger circ is creating so much head in the return manifold it's stifling the smaller circ. Try running the smaller by itself and see if you get a different response.

@Paul48 - I'm not running both circs. at the same time.

PipeJr

Gordy said:

Heat loss Bumped

Just a bit lost on your remark? A little help?

hot_rod

PipeJr said:

@Paul48 - Pumps and 4 way configuration (Secondary loop) determined by Taco design engineer.

Paul48 said:

Forget the loop around the low temp loops. It won't work.

- wouldn't having a loop around the low temp loops using T's for each circ. hydraulically separate these two zones?

@hot rod - so your saying I have to use (2) expensive 4-way mixing valves?
No, jut one mixed down temperature zone, run the boiler on ODR or fixed temperature

Paul48

You never acknowledged the last time I told you, that you still had not gotten all the air out. If you are running the small loop by itself, and still can't get setpoint temperature at that manifold, the loop is still air bound.

Paul48

What size is that 4-way valve?

Gordy

What are your emitters? Radiant? If so what type of assembly detail?

Gordy

PipeJr said:

Gordy said:

Heat loss Bumped

Just a bit lost on your remark? A little help?

I bumped your heat load calc so we can review it.

PipeJr

Boiler loop is 1.25" the Secondary is 1", Pex is 1/2" ; high temp emitters are Cast iron radiators feed thru 1.25" main to 1/2" (using venture T reducers) and low temp is under floor Pex.

Rich_49

PipeJr said:

Paul48 said:

I theorize that they are pumping against each other. The larger circ is creating so much head in the return manifold it's stifling the smaller circ. Try running the smaller by itself and see if you get a different response.

@Paul48 - I'm not running both circs. at the same time.

So you're saying that those 2 zones never call at the same time ? Doubtful .

Whose manifolds are those that you are using ?

What Taco design engineer gave you that layout ?

Where did those heat loss figures come from , did someone calculate them or are they from a program ?

Please forgive the pun , but where is the cardboard box that this is installed in reside , atop Mount Washington or maybe the arctic circle ?

These numbers would suggest that you somehow require 86.2 BTU sq ft for 2 beds and baths (?) and 126.4 BTU sq ft for the dining room ?
How was the information entered , is the second floor 2 bedrooms and 2 baths ?

Gordy

Don't take this the wrong way. We are all trying to help you. I know your initial question was not what things have lead to. However we all see time, and time again people come here mostly after it's to late. Many dollars have been spent, and things don't work.

Everything revolves around a PROPER heat loss calculation. I'm not seeing that, and neither is @Rich.

If you'll answer questions we ask we will try to help. You may, or may not like the answers, but hydronic is a science.

You can only get 35 btus a sf out of a radiant floor panel. That's because the floor panel can only be 85 degrees or discomfort is an issue to foot traffic. If you have hardwood flooring that temp drops to 82 degrees as wood flooring manufacturers get all upset their product will fail.

Now that's a decent radiant panel detail of which is.

Pex in concrete
Pex in gypcrete.
Over the top sandwich with heat diffusion plates. Prefab panels such as warm board, sun board, Roth panels etc

When you start going under floor panel output goes south in a hurry.

Examples
Staple up with plates
Staple up no plates
Ultra fin
Suspended tube.

The last examples will require much higher water temps in descending order. Expect maybe 15 btus a sf from suspended tube with no plates

Outputs with all radiant panels decrease the higher the value of the floor covering goes.

As I, and @Rich have noted your loads are very very high, and if correct which I doubt. You'll never heat the space with radiant alone.

So let's get the first step ironed out so we are not repiping, and repiping, and repiping.

PipeJr

venturi

PipeJr said:

Hello All, this is my very first post and first go @ setting up a multi-temperature system.
All constructive input and questions are welcome. (Have lots of data)

@Rich

Excuse the Pun but I also like to call young kids stupid because I'm more intelligent with life experiences!!!

complete Pun, jerk. thus why I'm quoting myself "Constructive Input".

Acehole

PipeJr

@Rich - sorry I've sucked up my pride when I first posted for help. I'd rather suffer than take punches from some narcissistic egocentric genius. I already have to deal with that @ work on a daily basis.

Please next time hold the puns to your self.

Rich_49

I don't quite understand your comment , don't need to . If you'd like to hear nothing more from me about your issues , just say so my friend . I was not calling you stupid nor anything derogatory .

Gordy

you will grow to appreciate the candor here if you are patient it is rewarding, and helpful. Rich made a point that is sharp to draw attention to the error(s).

PipeJr

"Please forgive the pun , but where is the cardboard box that this is installed in reside , atop Mount Washington or maybe the arctic circle ? " @Rich

Not sure how would you take this banter? If you went to the doctor for a checkup and he made some type of remark to you similar to this how would you take it. I did ask for constructive?

PipeJr

Personally I don't mind re-piping its fun if you don't have to do it for a living.

Paul48

@PipeJr

Life experiences will teach you not to slam doors when you get angry. @Rich is one of the finest radiant designers around. His critique might have been turned to what you call "constructive input", if you had asked for his help. You need it badly.

Rich_49

PipeJr said:

"Please forgive the pun , but where is the cardboard box that this is installed in reside , atop Mount Washington or maybe the arctic circle ? " @Rich

Not sure how would you take this banter? If you went to the doctor for a checkup and he made some type of remark to you similar to this how would you take it. I did ask for constructive?

Nobody can give you constructive input without knowing information . The pun was that the loads shown would be similar in an Amana Refrigerator box , of course unless the house were at one of those weather stations . If you'd like to discuss your issues and get to the bottom of them and fix them I'd be more than willing to help .

If you'd like to continue calling me by labels because I asked about your leaky or not leaky house , I'll leave the conversation , as stated before .

Gordy

May we continue?

Would you agree your heat loss calcs are not correct?

If they are you can only get 72 k out of 1" pipe at 2-4' per second. That's a flow rate which is high enough to move air back to the air removal device, and low enough to not cause excessive velocity noise, or pipe erosion.

We like to design system flow rates to use the smallest circs possible. For efficiency.

Think about that. If all loops at the supply manifold were equal loads that's 9k per loop. Your heat loads calculated are over twice that.

The universal hydronic formula is your friend in designing systems.

Gordy

When viewing those panel outputs pay attention to the supply water temp of 110 degrees. That's why they are lower than I stated in my other post. However it gives you an idea of how different types of panel assemblies, and their corresponding outputs.

PipeJr

Back to the point.
Calculations where manually completed using information found on the net and Calculators (http://www.calculator.net/btu-calculator.html). The information was validated thru a Taco technical rep. They helped me verify the size of the circulators and recommended the 4-way + current low-temp piping (minus doubling up the return manifold - my idea). Radiant is under floor directly mounted using dispersion plates to the bottom of 3/4" thick Oak HW and 1/2" subfloor/backer/Ceramic Tiled. The house was built in 1908 (blue stone foundation deco block exterior/2x4 framed interior), I've gutted, insulated, wired, plumbed, etc..

Paul48

That BTU calculator is ridiculous. It gives you a btu requirement for a 10 x 10 room that might be accurate if you had open windows. Re-do one of the 20k rooms using this, and see how far you're off... http://www.slantfin.com/slantfin-heat-loss-calculator/

PipeJr

wow.. spot on man!
Let's put it this way the large manifold (6 loop) is working great!! Using 120 f and only losing 5 f coming back. Outside temp is 7 f and inside 70 f; boiler firing about every 45 minutes.
-Changing the boiler loop to properly T off the high temp loop tomorrow. (won't matter much seeing that I'm priority zoning it.

@Rich - calling you out; you want to redeem yourself, figure out how I can pipe my low-temp zone (post 4 way to eliminate smaller pump from being taken over by my larger when both stats call at the same time). I would completely forgive you and disregard your rude comments. : )~

Gordy

The taco rep gave you component sizing based on information given to him. He's not there to say your heat load calc is right, or wrong. He sized components to the load given.

As @Paul48 said that calculator you used is not even close. That's not even a thumb rule. If anything it was made to sell bigger than needed equipment.

Load calcs are as precise as the information loaded. The more accurate the information, and the more inputs the more accurate the calc. Asking a room size, and poor, good, or best insulation type is way off the mark.
Try the slant fin you will see the difference, and its padded.

50 btus a square foot or more is a submarine with screen doors.

30 is high

20 is average

What centers is the pex spaced at?

Are the joist bays insulated? Very important with detail in sealing the rim joist area.


You have a little more than r 1.5 for flooring you have to push btus through.