HELP - WILL THIS WORK?

Darek_NYC

I am about to replace my old steam with radiant heating. DIY. While renovating the basement I have access to install floor heating for the basement and floor heating for the 1st floor (from underneath). I need the heating on the 2nd floor so I want to snake the pipes for hot water radiators. One combi boiler - 2 low temp zones, 1 high temp zone. There are so many different designs on line.
After research I came up with my own design (it scaled exactly to available space in my mechanical room):


Will it work?
Thank you for your feedback.

ChrisJ

Ok.

Who's going to say it?

Jamie Hall

not me... taken as read.

mattmia2

Does the boiler have its own circulator? It varies by which boiler you are using. Also, should connect to the primary loop without that connection short circuiting it.

Darek_NYC

I need to pick-up your brains on this. The steam piping is down the boiler and pipes in the boxes. Winter is coming and I have to cut and solder these loops. Please, if you see any flaws let me know Please!

I am thinking about reducing 1 1/2" to 1 1/4" on primary loop and 1" to 3/4 on secondaries. It just looks oversized for me. For some reason, manifolds supply is 1". Do I lose a lot of flow by reducing? Any thoughts?

HVACNUT

As soon as I saw "DIY" and "snake the pipes", I signed. 

mattmia2

Read this:
https://www.caleffi.com/usa/en-us/technical-magazine

The math you need to do will tell you the answer to your questions.

Darek_NYC

@HVACNUT I have the 2" holes after steam pipes all over the house. I don't need to rip-off the whole walls to run the pipes. This is what I meant by "snaking". I saw what few certified plumbers did in my two houses (for a big $$$) and I am choosing DIY since then.

Darek_NYC

@mattmia2 - thanks, I didn't see it before. Looks like a lot of good stuff.

Jamie Hall

I said I wouldn't say anything about the fundamental error, so I won't.

However.

I will say this: unless the system has been designed -- from the very beginning -- correctly, it is unlikely to work properly, if at all. This isn't a matter of pipe sizing. This is a matter of starting at the beginning, and doing a full heat loss calculation for each space. Then, if you are using floor radiant, determining first, whether the floor can deliver enough heat at all and then, if it can, determining the correct loop spacing and arrangement to do so, as well as the required water temperatures. The same thought applies to the hot water radiators. How big are they? What flows do they need at what temperature(s).

Then, and only then, can you select a boiler and control system to supply the needed flows and temperatures, and then -- finally -- you can design the manifold, pumps, and piping necessary to move and control those flows.

I hope you have proceeded from the beginning to the end, and not the other way around...

Darek_NYC

Thank you @Jamie_Hall. I did some math but is a lot of guessing in it anyway. I got some numbers about heat loss in my type of building as well about the floor heating output and radiators. I spaced the boiler accordingly to 199000 BTU up to 9.3 Gal/min. All circulators came to UPS15 or Taco 007 (I am on the budget). I think I did all correctly, but maybe one of you see the error I could oversee.

Darek_NYC

And... I hope that flow regulators on each loop will help compensate for the errors (gues data) in my calculations.
Are they helpful?

JUGHNE

So your first floor will have low temp radiant floor heat only?
How many sq feet is that?

HVACNUT

Darek_NYC said:

@HVACNUT I have the 2" holes after steam pipes all over the house. I don't need to rip-off the whole walls to run the pipes. This is what I meant by "snaking". I saw what few certified plumbers did in my two houses (for a big $$$) and I am choosing DIY since then.

Your right. That was uncalled for. But sometimes you have to get a pro. Penny wise, pound foolish applies. 

Jamie Hall

Um. Well, 199,000 BTUh is quite a bit. Consider that the main building I care for is 7,000 square feet and uninsulated, and only takes about half again as much heat (327,000 BTUh) makes me wonder about your calculations (New England hills -- minus 10 F design day).

You would be well advised to start with a Manual J calculation of the heat loss for each room and in total. There are several calculators on the 'net for that -- Slant/Fin has a very good one. Then go back and check the boiler size. An oversized boiler will be a very expensive error, and one that is easily avoided. You'll need the room by room heat loss to determine the spacing and lengths of loops anyway.

Darek_NYC

@JUGNHE - I decided to have only radiant on the first floor. It is about 600 sq ft of mainly open plan (kitchen, dining, and leaving the room with openings and no doors between them) It comes to 3 loops of 300 ft 1/2 pex. I will run it as a one zone (circulator). My hose is attached and two walls have neighbors. I have a total of 6 (new) windows and not bad insulation. Now I decided to get the second-floor bathroom only floor as well thanks to removing the ceiling under it for new bathtub installation. I will make a separate loop and zone for it. @Jamie_Hall the combi-boiler I am using has a regulated BTU output ranging from 18000 to 199000. I did all calculations and piping/circulator sizing seems OK. I am looking for an experienced eye to look at my schematic and catch the error if any.
Thank you ALL for your attention!

pecmsg

NYC

Whos the Licensed Plumber and Gas fitter doing the work?

hot_rod

To answer your question, yes the piping is correct.
I suspect like many you chose the 199 combi for the 4 gpm DHW output? Combi boilers have a circulator inside.
Granted it may be too large for the heat load, but with a 10-1 turndown and some limiting functions used, it should behave fine.
Pipe size depends on the load in the various zones, assume the max boiler output is 170K, that would require 1-1/2" primary loop, at 20∆ operation. I suspect your load may be lower? 1-1/4 is probably adequate.

Ironman

Did you install extruded aluminum heat transfer plates under the floor?

The square footage of the room doesn't determine whether a radiant floor will provide sufficient heat. It's the ACTUAL heat loss vs. how much output (in btus) the floor can deliver.

As Jamie so clearly stated, it starts with proper design and that starts with an accurate heat loss calculation (Manual J). This is math and physics and their laws don't make any concession for one's budget.

Another consideration is that your radiators output will be reduced to about 2/3rds of what they were on steam - unless they're steam only rad's. Then they won't work at all.

Steamhead

ChrisJ said:

Ok.

Who's going to say it?

Some folks think they'll save money that way..........

https://forum.heatinghelp.com/discussion/145002/actual-savings-over-steam-heating

josephny

This feels like a good mystery.

But a good mystery that doesn't get all tied up nicely at the end is very unsatisfying.

Someone care to point out the big basic initial design error visible in the original layout (for the curious and eager to learn among us)?

Thanks!

Jamie Hall

I kind of think we lost the OP, @josephny -- but the initial, and critical, error was removing the steam. Pretty much everything after that was a matter of tidying up the wreckage. The second error was that apparently no heat loss calculation, room by room, was done -- therefore no way to determine whether the radiant floors would even work. But I don't suppose we'll ever know.

josephny

Jamie Hall said:

I kind of think we lost the OP, @josephny -- but the initial, and critical, error was removing the steam. Pretty much everything after that was a matter of tidying up the wreckage. The second error was that apparently no heat loss calculation, room by room, was done -- therefore no way to determine whether the radiant floors would even work. But I don't suppose we'll ever know.

Thanks, Jamie!

Yep, I got it. My first post (more precisely, the responses to my first post) taught me that there is no getting around starting with a heat loss calculation.

I hope to be posting my completed first project in several days -- looking forward to hearing how I can improve it.