My radiant is not keeping up

Ericjeeper

I have in slab radiant.. 3,000 linear feet of tubing in 15 seperate loops , eachone has a flow valve. My design calls for as much .53gpm per loop on some of the loops. and I can't get it..I am running a 010 taco bronze.. closed loop . heat exchanger off of a water heater.. No problem with the heat exchanger keeping up.. just everyone is telling me that I need a higher flow.. which makes sense due to the design-heat loss analysis. Can I just replace the 010 with a 013 bronze and it should do the trick? Or do I have other issues?
I have at times a sixty degree delta t. other times it is as low as 30 degrees..
Right now here in Indiana it is colder than a well diggers butt.. -2
I read where the 013 is most suitable for an open loop.. and I have a closed loop system.
Even before this really cold snap.. my larger areas.. like living room-dining kitchen.. which is comprised of four loops.. The perimeter of the floor would get warm.. and leave the center room temp.. and that would satisfy the T stat, Now I can not even satisfy the stat. I am using a BOCK fuel oil fired water heater.
Thanks signed "Chilly in Indiana"

Bill Nye_2

Eric

What is the size of your tubing? 3/4, 5/8, 1/2, 3/8? Spacing?

Big Ed

Loops

You mention only one circulator and "Flow Valve" per loop ..... Do you realy mean "zone valve" ?

eleft_4

My radiant is not keeping up

You say you need 7.95 total flow. 009 will fit in place of the 010, the 013 may not, it's the head you need to increase.

Merry Christmas

al

John McArthur_2

Go to your heat load

Go back to the system design and look at the feet of head needed to overcome the pressure diff. The Taco 0010 delivers a lot of flow but low head pressure. You will also need to look at the entire system versus just the readiant loops. For example if your pump is on the return you will need to find out what your boiler develops for pressure through it. You will also need to find out what the resistance is on the "flow valves ". (Perhaps you mean telestats ). When figuring out the head pressure of the manifold you don't add them, you takethe worst one....Good luck.

Ericjeeper_2

1/2 inch Mrpex 12 inches on center

I have a 3200 square foot home. 15 loops on seven wall mounted thermostats. I have a zone valve on each loop, as well as a flow regulating valve. I am using a 010 taco.. someone mentioned I need more head pressure.. Would a 009. be better than going to a 011? I am the homeowner, and carpenter by trade. I did install this system myself..

S Davis

Radiant Design

On your heatloss it should tell you what your max headloss is on your loops ( keep in mind if loops were run longer than listed on the manifold report you will have to adjust your headloss) you will also need to figure the supply and return piping and your heat exchanger, you should be able to get a pressure loss chart for it.
The other thing I would look at is if you have more than one manifold location you need to ballance flow between the manifolds, I have seen systems that had the correct pump and all of the loops were ballanced correctly but one manifold was closer to the boiler and would get more flow.

S Davis


Apex Radiant Heating

eleft_4

Check the garph on this pdf

Nron_9

low flow

what is the head loss on the heat exchanger from your tank flat plate style have a large head loss , talk to who supplied the parts they should beable to help

Ericjeeper

my heat exchanger is a coiled tube

I have a 21 foot coiled tube..in a galvanized box.with a great exchange rate. almost 100 percent.. I am not sure of the friction loss. But I am real happy with my exchange rate.


I am looking for the specs on my 010 taco bronze to compare to another size pump. such as a 090 taco Bronze as mentioned in prior post.

Floyd_7

The 0013 will give you....

higher head and flow.... it is a 6-1/2" pump and will fit for you......
If it were me I think that I would have split things up and had a pump for each t-stat, then you know you gots the flow you need...

Floyd

Ericjeeper

I would have had seven pumps to maintain? Plus no matter how many pumps I have.. they all have to go through the same heat exchanger.. so I opted for the keep it simpler method.. maybe I was wrong. I will order a 013 Taco bronze Monday morning if the consenses feel it will do the trick for me.. .

Ericjeeper

Thanks to all for helping me with my issues..

Merry Christmas to all.

Jed_2

It's funny nobody

suggested the need for DPV(Differential Pressure Bypass) valve for this system. My quyick calcs indicate he has about 200-210'/Loop. Now tell me what the PD is for 1/2" pex through 210'. True, I don't know what the HX develops at Eric's flow rate, but I ran HDS for a trial run(only 12 loop max), and the head loss is well within the capabilities of a 0010(HX ?). But, certainly with a 0013, coupled with TELESTAT ACTUATORS, don't you think there could be velocity issues?

Just wondering,

Jed

Doug Wagoner

heat exchanger or pump problem

What size and type of pipe did you use for the coil? Do I understand that it is 21 feet long? There may not be enough area on your 21 feet of coil to transfer the heat from the galv. box. Describe this exchanger in detail. You may not have a pump problem but a heat transfer problem or it could be both.

Ericjeeper

There is 21 feet of coiled pipe.. all looped neatly inside a glavanized box.. The box is dry and insulated..mainly gives you a way to hang it The coil is actually double wall heat exchanger.. I assume a 1 inch type l soft with a 3/4 in it and a half? I have not seen the inside of the coil.. But I know I send in hot water on one side and get hot antifreeze on the other..
I am for sure I have flow issues.. as when just the garage four loops are on I can meet the .5 gallon per minute per loop called for by my heatloss.But when more loops open up my flow dimenishes. Thanks all.. I will have the 013 tomorrow.. and will install it and let you all know my results..

S Ebels

A very good reason

" I have seen systems that had the correct pump and all of the loops were balanced correctly but one manifold was closer to the boiler and would get more flow".

What have you seen done to address this problem?

We always reverse return when dealing with multiple manifolds in more than one location. Saves a lot of time fiddling around with balancing valves.

S Ebels

I agree 100%

A 0013 is a serious circulator. One that I don't want to pay the electric bill for if I don't have to. A 26-64 Grundfos would likely be better suited. The 007 is hitting the head so it can't be all that high. He's not able to meet his total GPM once all the zones open so he needs more GPM at that head. Not more head.

If that made any sense........????

Jed_2

follow-up

Re-reading the threads, it sounds like too much loop length diversity. The heat loss analysis is fine, if the tubing was actually installed accordingly. Fat chance? maybe. The only thing, other than a kink or blockage of some sort, which could cause such variation in flow/pressure drop variation, is the loop schedule variance from good radiant analysis design. What is the zone/loop configuration as installed?

Who wants to venture a guess? Eric?

Jed

van_2

How Much Antifreeze?

You mentioned that you have "hot antifreeze" coming out the other side of the heat exchanger. Antifreeze is harder to pump than straight water. How much antifreeze do you have? This may be why the pump is not performing.

S Davis

Globe Valves

We use Globe valves on each manifold return in the boiler room because we run a separate supply and return from the boiler room to each manifold.


S Davis


Apex Radiant Heating

Ericjeeper

I think my system held about 27 gallons of fluid. and 40 percent of that is antifreeze.. Only reason I used antifreeze is my second manifold is fed overhead, Plus I worried about my slab near my overhead doors. Hopefully tomorrow the UPS guys will get tired of hauling the pump around and actually leave it at my door.. I ran a tracking on it today and it said it was to be delivered on schedule the 29th.. well is 9:30 pm.. I doubt they are still planning on delivery.. LOL Oh well so much for the extra 11 dollars for second day air

kevin coppinger_4

1/2 loops coming off what size manifold?

you should be shooting for a 10F delta T...kpc

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S Davis

Manafold

Are the loops you are having problems with on the manifold farthest away from the boiler?

S Davis

Apex Radiant Heating

Ericjeeper

I have one loop on the far manifold.suffering

and four loops on the garage manifold suffering.

ScottMP

What am I missing

Why does this man have a Bronze pump ?

He said it was a closed loop and off a heat exchanger ?

What pump is running form the HWH to the galv. tank and what pump is running out to the loops. If he has a closed loop of the heat exchanger then wny Bronze ?

Scott

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S Davis

Auquapex

He is using auquapex tubing.

S Davis

Apex Radiant Heating

hr

Did you contact the manufacture

of that HX for flow and pressure drop specs? Most brands will provide a chart showing pressure drop at various flow rates. You need this info to properly size the circ pumps. And glycol will make a difference in pump specs!

I wonder that that is where the constipation is?

Did you mention a galv box? Hope the glycol is not in contact with the galv!

hot rod

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Ericjeeper

The galvanized box.. just holds the coil heat exchanger. It is a dry box.. with insulation.. I should have never mentioned this glavanized box.. it has confused everyone

Weezbo

turn the temerature higher on the bock water heater control.

may haps the exchanger needs more btus ....to meet the demand.

Jed_2

Something is not adding up

Eric, can you make some kind of sketch of your system, and post it here? You say you have 15 loops and 7 t'stats, with a zone valve on each loop, along with balancing valves. And then in another post, you mention the furthest manifold(garage, I think), and another manifold. I'm not following the need for the zone valves on each loop. Are the zone valves for each manifold, and the 0010 providing the flow for all the manifolds; or are all the loops on one manifold, with telestats(zone valves) for each loop?

Yes, the antifreeze could affect flow somewhat. 27 gallons is about right for 3000' of 1/2" pex. But, how much supply and return piping to the HX? Is there a header for the manifolds? Additional water content. What size is the header? What size are the S&R's for the manifolds, if there are multiple manifolds. What are the runout lengths of the S&R's to the manifolds? How is the header piped?

It's just not clear what your system piping design actually is. If I remember, your HX is made of a good size tubing, but don't know much about it's coil structure; it may or may not have a significant PD.

Just not clear with what you have there.

Jed

Ericjeeper

Unable to make any sort of sketch, pics though

Ok I have two different manifolds.. One has eight telestats. on two seperate thermostats.. four loops per.. Four loops go to the garage., the other four go to the great room. Then 30 feet away S&R 1" soft copper.is my other manifold.Which by the way is plumbed across my attic and dropping back down. with seven telestats. and five seperate thermostats. . I am using bronze housing by choice. I figure the less contaminants. the better.
when it is moderate temps out I have no problem with supply of water. But when it plummeted last week.. I was lacking the flow I needed to meet design.(with all loops open I lacked volume to warm to what I felt was proper.
My heat exchanger has an excellent transfer rate.. maybe once I up my flow a little bit.. it might fall off a bit.. but that will help.. My design does not call for 120-138 degree fluids.

kevin coppinger_4

did you ...

use etylene glycol(automotive) antifreeze in your system? kpc

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Ericjeeper

I sure did. NT