BIG radiant home question

hr

would be 4.4 valves per manifold. With small diameter tube you end up with shorter loops, generally around 200 feet.

If the tube is 6" on center, common with those small diameter tube panels, than the multiplier is 2.10.

10,000 suquare feet COULD require 21,000 feet of tube. At 200 foot loops that would be 105 loops that would need telestats on every loop. If you push 250 foot loops that would require 84 telestats.

Heck you could weld with a transformer sized large enough to operate that many telestats :)

Even if a manifold has 6 loops on one zone, you would need a telestat on every loop to open them at the sanme thermostat call for heat!

This is why it MAY make more senses to use a non valved (telestat type) manifold and use a zone valve to operate all the loops on that manifold.

Clear as mud?

hot rod

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Steve Minnich_3

BIG radiant home question

OK-here's the deal. Huge new home, 10,000 square feet, radiant throughout. Job is sold.

I'm using two Buderus boilers which will be staged and share equal run time, a Triangle Tube Smart 100, primary secondary piping with variable speed injection mixing(3 different water temps), outdoor reset (tekmar 262), Quik Trak for most of the home(hardwood), and 19 zones using tekmar 511 setpoints.

Here's my question.

What are your opinions on using pumps, telestats, or zone valves to zone this home?

If I use telestats I'm going to need about 75 of them, add'l transformers, and zone control modules. That's alot of electro-mechanical devices to isolate 19 zones.

Pumps would seem to be very redundant, overkill, and unnecessary. IMHO. I already have the two individual boiler loop pumps, the single primary pump, the three VSI pumps, and three secondary pumps(one for each water temp). Each of which is then piped to a number of manifolds.

Zone valves would seem to be the best choice. No waste, redundantcy, etc.

What do you think? I appreciate your input.

Steve Minnich

don_144

Personally

I think lots of zones are redundant without a thermal break
between the zones.

I mean every time I zone a bunch of rooms on the same level,
I ask myself why.

Why the valves are lifting,why is it that this room is the same temp as the room across the hall on it own zone,why did
I even bring up zoning in the first place.

Why,why,why!

Steve Minnich_3

Thanks Don

Actually this house has more doors than most that I've done, alot of seperation. Whether they're actually used or not is something else.

Steve

Al Letellier

multli zone radiant

We did on very similar a couple of years ago, except with one boiler. We used the Viessmann and their system of using motorized mixing valves (2 Temps) and normally open zoned valves. The stats then became local high limits and draw power only when the zone is satisfied. Properly adjusted controls make this system the most economical to run but has some drawbacks. You have to use cooling T-stats and everything works in reverse to the common system. Can make troubleshooting difficult for anyone who didn't install the system or who wasn't trained, but it works great and energy comsumption is quite low compared to all those circs or telestats.

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hr

How many zones?

How many per mixed temperature station? For me I would use 3 circs from each mix station than a good zone valve. Erie works for me. Use up to 4 ZVs without the need for a pressure bypass IF these are low head circs.

Could be an application for a mini tube system if the manifolds are remote from the boiler room.

hot rod

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don_144

I sure

would love to see that setup Al.Sound like what I been hoping or wishing to do,just not sure how to go about it.

Steve Minnich_3

hot rod

There are roughly 6 zones per mixed water temp, one of them has seven.

I'm using 5/16" hepex.

I don't quite follow you on the 3 circ.s/ zone valve thing?

Thanks

Steve

Steve Minnich_3

Al

That's a pretty interesting control strategy.

You're right though, unless there were flashing neon signs alerting the future service tech., he or she would be in for a frustrating service call.

Thanks

Steve

jerry gorski_2

zoning

75 telestats in a 10,000 sqft home is way overkill.I would suggest you sit down with the home owner a discuss their lifestyle and zoning needs.Finf out what they expect from their radiant system.
Quite often in our haste to do our best we kill the job with enthusiasm

Steve Minnich_3

Hey Jerry

Many of the telestats will be piggy-backed(paralleled) together to achieve the end result of 19 total zones.

I agree that it is overkill. Somebody representing the telestats suggested that route.

Steve

jerry gorski_2

have you talked to the homeowner as to what he expects?
Let the homeowner make a written commitment.

joel_19

been there

Done that and i'm with Hot Rod . I wouldn't go all pumps or all those telestats . I'd use pumps for each temp or maybe one for each wing of the house and then try to work out using traditional stats.

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hr

I suspect that system will require

high head pumps, with small bore tube like that? It is generally designed around tight delta T's also. Your design should indicate pump spec.

This article will better explain why you need a bypass valve when you have multiple ZVs and high head pumps.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,29498,00.html

I believe we are dangerously close to having a delta P pump available that would be an ideal fix for this issue. Rumors have it Wilo has that pump here in the US of A. I've seen pictures, but have yet to lay my hands on one

I am reworking my own system this fall to all low temperature emitters in place of my high temp BB system. I am looking at a constant circ system like one of the concepts in this article, linked below. I like Erie Z valves and may use a simple inexpensive 3 way zone valve to accomplish the task.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,113669,00.html

hot rod

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Cosmo_3

Agreed

On the big job I had last year, I used a Vitidens boiler, 2- 3-way motorized mixing valves and sized the pump for each mix to handle the required downstream gpm requirements. I installed remote manifolds, and was able to get away with 12 manifolds for 17 zones. Only a couple manifolds had thermal loop actuators, the rest of the manifolds are controlled with zone valves. The pumps stay on all winter controlled by the heat curve, and the mix of zone valves and thermal loop actuators work as limits, only turning off flow to prevent overheating. I started that baby up last spring, and it purred all winter, ahhhhh.

Cosmo Valavanis

Dependable P.H.C. Inc.

S Davis

Delta P Pump Set Up

hot rod,

Grundfos has a variable speed pump(UPS26-96VS) that will take a 0-10 volt DC signal to ramp up and down, we then use a wet to wet differential pressure transducer to control the pump, we have used it on a couple of large jobs with small zones.


S Davis

Apex Radiant Heating

Weezbo

i would bag all those telstats....

someplace along the line radiant heat balances its self out sort to speak, seldom does it respond (Ramp) real quick , i would like to suggest you take a look at the taco pump block ,just maybe you could pull longer zones back to a station and combine more of the loops to act as a single zone off the block... you would have to do your homework as it were as there is a rather small injection pump and the system pump is like maybe going to have to slave a bit on 5/16ths...

jerry scharf_3

I'm not getting it

Steve,

If you have 19 zones, why would you have 75 telestats? Are you thinking of these as replacements for balancing valves? My gut reaction is 75 things to break.

I like remote manifolds with a few telestats on each.

If you want to talk about it more, a drawing of what you're proposing would be a great help. Also average amd maximum tube lengths will help understand the pumping needs.

jerry

Weezbo

Well at the onset telstats seem like a deal. like hot rod says

though it would be alot less wire an mega watts to control them off a zone for that set of loops.*~/:) or perhaps all the heat loss off that many of them could be added into the kw's requiered to heat the home and all would be well with the world. only thing is is that you would have an electrical ,in wall radiant electrical heating system...pull the loops back to headers and pull them back to a control point station and reduce the control stations to a minimum....think it that way even mix the floors on the distribution isnt all bad,then should something go down you have some coverage one every floor and a little larger margin of error in getting the system back up......as a thought. you can bundel the lengths comming back and send them thru larger holes or a soffit arrangement as another salient point of interest...

Steve Minnich_3

Yes, I agree

> would be 4.4 valves per manifold. With small

> diameter tube you end up with shorter loops,

> generally around 200 feet.

>

> If the tube is 6"

> on center, common with those small diameter tube

> panels, than the multiplier is 2.10.

>

> 10,000

> suquare feet COULD require 21,000 feet of tube.

> At 200 foot loops that would be 105 loops that

> would need telestats on every loop. If you push

> 250 foot loops that would require 84

> telestats.

>

> Heck you could weld with a

> transformer sized large enough to operate that

> many telestats

>

> Even if a manifold has 6

> loops on one zone, you would need a telestat on

> every loop to open them at the sanme thermostat

> call for heat!

>

> This is why it MAY make more

> senses to use a non valved (telestat type)

> manifold and use a zone valve to operate all the

> loops on that manifold.

>

> Clear as mud?

> hot rod

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 144&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

Steve Minnich_3

Yes, I agree

That was really what I was thinking. I just wanted to make sure I wasn't missing something.

Thanks for your help HR and all the guys.

Steve

Steve Ebels_3

I try to

Keep it simple. After all, I may have to come back and fix something there someday............

I try to design one pump per temperature or in the case where we have a second remote manifold location, maybe another pump to service that location. Sometimes I control them with a reset control and sometimes I run them off a circ relay panel controlled by either the boiler control or a "main" thermostat. It depends on the job's requirements. I guess my bottom line is how can I use a given circ to the best of its performance capability. In other words, if I have a zone(s) that call for only 1-2 gpm I'll try to find a way to circ that zone along with another. Like Hot Rod said, zone valves work nicely for this application.

Personally, my design philosphy steers clear of a wall full of circs pushing way less than what they are rated at. About 20-30 of 'em all neatly lined up in a row look impressive as all get out. But! is that really what the job required and are you really designing an efficient system when you suck up a couple KW per hour to wheel 15 gpm around the horn?

Look closely at your required flow and developed head and make a decision based on that. Knowing you, it'll be the right one.

Unknown

Maybe consider a header with the highest temp water, with a couple of distributed mix stations in the home? then each zone could pull off the header, and if you have an area with several smaller zones, you could telestat them, or if you have a few larger zones, you pull off and hit the zone valves...

depends, I guess, on how spread out the house is. Might be easier than running 10-20 sets of manifold feeds.

Paul Pollets

I Agree...

Radiant in large homes often requires (2) radiant mix temps (slab and overpour) and sometimes a high temp circuit(radiators or air handler HW coil); and the DHW Indirect Tank pump. It's very easy to set up a large system using only 4 pumps. I've noticed that even qualified radiant designers get carried away with pumping to every manifold...Then again, using 5/16 tubing, presuming a QuickTrac or Climate Panel install, should consider the new 3/8" panels. It will greatly reduce pumping requirements.

Following the principle of constant circulation, zoning should occur on a room by room basis using telestats. It is not, repeat NOT necessary to install a thermostat in every room. It will defeat the efficiency of constant circulation. It's best to ask how the owner's will use the space and use thermostats/telestats sparingly. Often we'll install the Tstats in bedrooms or home office only. If there are specialty use rooms (exercise, etc.) we'll use a stat in those locations.

I had a client who requested 30 thermostats in a very large home he was building. There were 30 rooms in the home and he had 12 children. I carefully explained the purpose of constant circulation and since he was installing a Euro boiler system, it would work better with only bedroom zoning. He replied gruffly, "he had the money, and simply wanted them". I complied. 6 weeks after moving in, he called me to have the Stats removed in all rooms but the master bedroom. The children had found the digital stats to be irresistable. His temperature swings were 20 degrees in every other room and his oil bill was off the charts. Since then, no problemo. Careful design allowed each room to be loop-tuned within 1 degree accuracy. Keep it simple.

I'd also recommend using a Wirsbo (or Danfoss) ProPanel(s) for near-boiler piping, to make your life easier.

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jerry scharf_3

yikes

As a controls designer, this seems wasteful and sure to cause problems down the road.

In plan 1 have 3-6 telestats on a manifold for a zone, all driven off the same thermostat. In plan 2 I have 1 telestat controlling water to the zone, and all the loops are fed in parallel. In plan A I have several times as many things to fail, and no increase in either control or performance. In plan B I may need to have two manifolds instead of one larger one in some places, but that would cut the run out length on the skinny loops. Either way you need balancing valves on each loop to keep the rooms comfortable.

So 1 zone valve off the thermostat and simple manifold. You can then collect the zones together off pumps to keep the number of pumps and bypass valves to a minimum.

jerry