system piping for TT prestige 110

brad_14

Hi Guys,

I am just about done my joist track install and am ready to order near boiler parts.

I will end up with 3000' of joist track split in two zones and 2500' in slab basement and garage in three zones all 1/2" and a Smart 50 DHW. My boiler will be the Prestige 110.

What do you think about the Superbrutes by Grundfos? The 26-99FC for main circulator and the 15-58FC for the Smart 50. I like the idea of fine tuning also I will probably add another 750' of 1/2 pex to the main when I finish a bonus room.

How about the fill-trol fill valve expansion combos? The 110-P seems apropriate.

My main ? is my near piping. I was planning on 1 1/4" but then I just realized the prestige 110 has a 1" supply for DHW and CH. Does it make any sense to up size to 1 1/4" with the boiler using 1"?

The zones I was thinking of using 3/4" with Taco EBV's any comment on these or should I just use the 570's? Is 3/4 sufficeint? I will use a taco 6 zone controller to give me a zone for expansion.

On the domestic cold in to the smart 50 I was thinking of using a Amrol therm-x-trol ST-5.

Thanks again, the help you all have provided during my planning has been awsome.

Brad

brad_14

Anyone?

I can't see why I would spec anything other than 1" for the main system piping if the boiler has 1" connections, True?

The near boiler piping is there any point going 1 1/4" up too the zone branches?

The DHW connection on the boiler too is 1" but the indirrect tank is 1 1/4" is there any point using 1 1/4"?

My origional design done by a local supplier spec'd 1 1/4" for all other than zone branches but they also spec'd a prestige 175 with 1 1/4" connections. But since then I have reasons and advice to belive the 110 will be more than capable of handling my loss.

thanks

McKern

btus?

how many btus are you moving?

brad_14

BTU's

Net I=B=R is 88 for this boiler and if all zones called for heat on a very cold day I could see it aproaching that.

The original heatloss done was calculated at 112 but the house is very tight and well insulated and I have been heating with a 61K BTu pellet stove all winter. So I think the 112 is very conservative.

McKern

Demand... not supply

No... What's the demand for heat from the house? What are you heating it with during construction? Better question, what is your heatloss? You had that on a building permit I would think... or at least it was used to try and size a boiler. It doesn't really matter much, they're all too big for ALL small homes that aren't leaky.

Perry knows heat exchangers and combustion. We need to get him to work for a boiler company. A 10K - 38K, that's the right ratio isn't it Perry? He needs to design a 10K to 38K boiler.... Before Honda does. Don't laugh they make a wicked snowblower. The Viessmann of the snowblower world. I have a Made in Wisconsin / USA orange Ariens.

Or better yet the Koreans. Are LGs now a high end brand?

Anyway, I'm rambling and Brad you should have an idea of the maximum BTUs for demand. Your boiler will only need to supply that much and can be piped accordingly. In a normal sized house with low infiltration and a very efficient heating system I doubt you'd need 1¼" pipe to keep up with demand.

Unless you're in Antarctica or the other pole... and you can use the full capacity of this boiler.

[Deleted User]

As Uni R said...

You have a LOT of math homework to do. Pipe sizes are typically made based upon loads carried, and not gut feelings or tappings sizes available. If in doubt, do the math. Once this is done, you will be in a better position to do the other math that needs to be done in order to correctly size the pumps.

Personally, I have 5,000 sq. foot homes running on Grundfos 1558's. If you want to drop a 2699 in there, go ahead, but I guarantee the hydraulic hiss will drive you bonkers, and you will be back here asking more questions.

Hydronics is a finely tuned science. Not a gut feeling. Following your gut feelings will generally end up causing things (pumps, pipes, boilers etc) to be oversized. As our gracious host says, "The urge to oversize exceeds the urge to have sex!!"

The consequences of oversizing boilers is not as great a problem as it was 5 years ago, thanks to modulating technologies, but the problems associated with oversizing other components remains the same. Wasted time and money, and excess velocity noise issues.

Do the math, get back with true numbers, and we'll help you fine tune your design.

It would be extremely helpful if you could give the length of mains, loads connected, and small bore tube lengths and loads connected to them as well. I have software that will tell you EXACTLY what you need.

ME

brad_14

The math is done

In my reply I did note a calculated 112K btu heatloss. I also noted that I have determined that that was overly conservative and one of the factors is heating with a 61K BTU pellet stove all winter.

The reason I came up with the max around the boiler net is for 2 reasons. If the 61K btu pellet stove is capable of heating the house in the coldest conditions I will say it is maxed too account for HRV loss(not currently installed) and the overall heat distribution not 100%. The garage heatloss is about 20K btu and is not heated by the pellet stove. So 61+20=81K btu + a little extra for a future zone in the bonus room. The other way I came to roughly this number is I manually calculated a couple rooms against the heatloss I paid for and came up around 20% lower so I just took 112K X 80% =89K. The one problem I found with the heatloss I did is the tables did not always go as high R values as they needed. I also posted hear and most responses indicated with a tight high r=value house the 110 prestige would be more than enough.

Now all of that asside I'm still trying to wrap my head around this one. If the boiler has 1" connections why would you use 1 1/4" with a 1" bottle neck? I don't mind using 1 1/4" if it will make a difference. I think my electrical/electronic background is playing delvils advocate. In electrical the max amperage(flow)is determined by the smallest wire. The prestige has a built in system circulator so the 1" is at the circulator.

Sorry for the goose chase but the real question is does it make sense to go from 1" up to 1 1/4".

McKern

Sorry...

When you said on 112 I thought you were meaning the 110 rating of the boiler because you were also talking IBR which is totally meaningless in the context of a modcon.

Anyway, with piping losses it is not just a matter of how restrictive some section is, it's the cumulative lengths at various restrictions. The volute in your pump is probably smaller than 1" but the water only has to speed up through there for a short distance. So the boiler piping is one inch but you can make the rest of the circuit circulate a bit easier. I would think that the heating side should be at least as large in the are of the closely spaced tees.

I used nearly all 1.25". Some 1" dropping down from the boiler and 1.5" along the primary section that has the closely spaced tees and the wye strainer just upstream of them. That was on a demand of well under 50 it would seem. Overkill I'm sure, but it looks nicer. ;-)

PEDRICK MECH

PIPING HEADER

YOU SHUOLD USE 1-1/4 MANIFOLDS AND PIPE THE 1" SUPPLY AND RETURN FROM BOILER INTO THE HEATING SYSTEM AS A PRIMARY SECONDARY PIPING SET-UP. THAT WAY WHEN YOU NEED MAXIMUM FLOW RATE THE ZONES WILL HAVE FULL CAPACITY DUE TO THE 1-1/4 PIPE SIZE AND NOT BE STARVING DUE TO ALL ZONES CALLING AT ONCE. ALTHOUGH I KNOW YOU CAN PRIORITIZE THE INDIRECT THIS PIPING ALLOWS FOR GREATER EXPANSION CAPABILITIES DUE TO THE PIPE SIZE ALREADY BEING 1-1/4. A 1-1/4 MANIFOLD ALSO ALLOWS FOR BETTER AIR REMOVAL BECAUSE 1-1/4 PIPING WILL SLOW DOWN THE FLOW THRU THE MANIFOLD DUE TO IT'S LARGER SIZE AND ALLOW FOR THE AIR SEPARATE FROM THE WATER AND ENTER THE SEPARATOR.

brad_14

That makes sense I will go with 1 1/4".

Do you know of any good references for pump sizing both suppliers have recommended using a UP 26-64 1 speed. But I should question that too since everything else they recomended was oversized. I was leaning towards the 26-99 3 speed because on low its output is lower than the 26-64 but sounds like that may even be too big.

Thanks again, I'm off to pull more pex. I can't wait until thats done only 5 more 250' loops to go. I'm doing it mostly alone so it is time consuming.

brad_14

1 1/4\" Manifold for zones

I see what you mean the 1 1/4" really would balance the flow better if all called for heat.

Thanks

Guy Woollard

Header

With the piping that you have described, the 1 1/4 P/S setup would not be such a bad idea. I would still recommend using the dedicated circuit for the Smart tank, as it will allow you the benefit of the outdoor reset function for the central heating side.. We have provided seperate wiring and piping connections for the indirect circ. and aquastat, so it should be a simple hookup.