Primary/Secondary Piping


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Old 12-30-09, 08:52 PM
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Primary/Secondary Piping

My first post here.

I plan to replace a very old boiler in an old house we just purchased with a modcon boiler & indirect hot water tank.

Boiler :: DSC08334Large.jpg picture by Subieho - Photobucket

The current system has cast iron radiators on both the 1st and 2nd floors, all set up as one zone. However, it seems that there may be multiple loops by looking at the current near boiler piping. I can't say for sure because the previous owner finished the basement, thereby hiding all the piping with sheetrock.

The is 1-1/4" copper feed pipe goes up to a T going in opposite directions with a gate valve at opposite ends of the "T," presumably to control flow.

The return pipes show three pipes joining to the main return pipe along the ground connected to a 1-1/2" copper pipe that wraps around the corner and returns to the boiler.

http://s759.photobucket.com/albums/xx234/Subieho/Boiler
/?action=view&current=DSC08336Large.jpg


Boiler :: Boiler picture by Subieho - Photobucket

Before I get into the more technical aspects of hydronics, I'm just trying to figure out a few basic things:

1) If I'm going with a modcon unit with an indirect tank, I need to pipe in a boiler (primary) loop, right?
2) If there are indeed separate loops for the 1st and 2nd floors, I'll eventually have a three zone system (1st floor, 2nd floor, and indirect water heater). What's the best schematic to achieve this?

I've been looking at the very good information on this site but can't find a schematic that would fit my case.

http://www.comfort-calc.net/primary-..._tutorial.html

Sorry for all the meandering as this is all pretty new to me.
 
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Old 12-31-09, 05:48 AM
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The manual for the new boiler should provide this information in it. Try looking there. They are typically available online.
 
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Old 12-31-09, 05:56 AM
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Congrats on the new home. Here's a suggested course of action.

Step one for your old house, is to get a real building efficiency audit, using a blower door test and thermal infrared imagery to identify insulation and air sealing deficiencies. These tests take a couple hours and typically run in the $200-300 range. It's some of the best money you can spend on energy, especially with an older house.

Step two is to develop a plan to insulate and air seal the house. This too is some of the best money you can spend. Insulation is fuel you buy only once and it pays back forever. There are good utility rebates and federal tax credits. See DSIRE: DSIRE Home for incentives in your area.

Step three is to do or have done a heat loss calculation to size the boiler to the reduced heat load of your newly upgraded building shell.

Step four is to figure out what boiler, zoning and control options you want. More on that later.
 
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Old 12-31-09, 06:37 AM
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Although I would not necessarily recommend this specific boiler, the piping diagrams are quite good.

http://www.htproducts.com/literature/lp-185.pdf

I would suggest some combination of diagrams 2A and 2C.

Differences:
- in 2A, use a pressure differential circulator (e.g., Wilo ECO or Grundfos Alpha) instead of a differential pressure bypass valve.

- in 2A/C, use a dedicated circulator for the indirect, and do the calculations for flow rates through the boiler to see if it can be piped off the boiler loop rather than the secondary loop.

And now that I think of it, that ends up looking almost exactly like Figure 32B of the Burnham Alpine manual, which is also very good.

http://burnham.com/pdf/Alpine%20I&O%209-09.pdf
 
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Old 12-31-09, 02:07 PM
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Thanks for the responses (and good wishes). I've done a rough heat loss calculation and come up with a heat loss of 136 MBUs for a 3600 squre feet two-story home. The house was built in 1930 and located along the New Jersey shore near Atlantic City. I used an outdoor design temperature of 13F and an indoor design temperature of 70F. The old cast iron dinosaur of a boiler is grossly oversized and rated at 285 MBUs input and 225 MBUs output.

We had an energy audit guy come out to take some notes in order to decide whether it makes sense to participate in a Home Performance with Energy Star Program. If it makes sense to go with the HVAC company he represents, they'll do a manual J calculation with blower door, and we'll need to decide whether we'll actually save money hiring them to do the install along with some other energy saving work.

Funny thing, xiphias, is that I'm already leaning very heavily toward the Burnham Alpine 150 and a 70 gallon Burnham indirect tank -- I know there are better tanks out there (e.g. Triangle Tube), but cost is a real consideration for us.

My regular line of work (computer software) is one that has been outsourced in recent years, and I, like many others, have lost some real money in the stock market. So we took the plunge and sold our remaining stocks to buy this place as an investment property, which we'll need to rent out in order to pay for the carrying costs. We hope to make this place our primary residence after our girls grow up, but for now, we'll only be using it during the off season.

In general, the house needs a ton of work, and I plan on doing much of it myself due to cost considerations. I'm fairly technical -- I do all my auto maintenance & repair (timing belt, overhauled a transfer case, etc...) along with almost everything around the house -- but this would be my first modcon install.

I've been trying to make heads and tails out of the the diagrams in the Burnham installation manual, but the Munchkin link xiphias sent helps me visualize how to do the retrofit.

Just clarify:
1) Both diagrams 2A and 2C show the indirect hot water tank (IWH) pumped off the secondary loop, right? The boiler loop is limited to the first little loop across the closely spaced T's and back to the boiler? If so, is the boiler loop primary in this case? I ask because the Munchkin diagram seems similar to Drawing #4 in this link:

http://www.comfort-calc.net/primary-..._tutorial.html

2) In the Burnham manual, I would most likely have to go with the 32B or 32C due to the difference in flow requirements for the boiler and IWH, right? I'll do calculations after I get a better handle on things to verify.

2) Because I would have at most 3 zones (including the IWH), would it make more sense to zone with circulators? I would need a total of 4 circulators -- Boiler loop, IWH, 1 zone to the 1st floor, and 1 zone to the 2nd floor.

3) Initially, however, I would pipe everything for 2 zones (one for the heating zone radiators and one for the IWH). I could always add another circulator or a couple of zone valves if the two gate valves do indeed lead to 1st and 2nd floor loops, respectively. For all I know, they may just be looped along the front and rear lengths of the house.

I wish I had taken a photo of the feed pipes when I was last out at the house, but this is a close approximation.

G=gate valve
C= circulator added for heating zone to radiators
^= 1-1/4" feed pipes and direction of flow

----------------->G>>>>
---------------------------^
---------------------------^
---------------------------C
---------------------------^
---------------------------^
-------------------Feed from old Boiler


I hope this makes sense.
 
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Old 12-31-09, 02:41 PM
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Originally Posted by Subieho
Just clarify:
1) Both diagrams 2A and 2C show the indirect hot water tank (IWH) pumped off the secondary loop, right? The boiler loop is limited to the first little loop across the closely spaced T's and back to the boiler? If so, is the boiler loop primary in this case? I ask because the Munchkin diagram seems similar to Drawing #4 in this link:

http://www.comfort-calc.net/primary-..._tutorial.html

2) In the Burnham manual, I would most likely have to go with the 32B or 32C due to the difference in flow requirements for the boiler and IWH, right? I'll do calculations after I get a better handle on things to verify.

2) Because I would have at most 3 zones (including the IWH), would it make more sense to zone with circulators? I would need a total of 4 circulators -- Boiler loop, IWH, 1 zone to the 1st floor, and 1 zone to the 2nd floor.

3) Initially, however, I would pipe everything for 2 zones (one for the heating zone radiators and one for the IWH). I could always add another circulator or a couple of zone valves if the two gate valves do indeed lead to 1st and 2nd floor loops, respectively. For all I know, they may just be looped along the front and rear lengths of the house.
1) correct.

2a) correct.

2b) zone with circs or zone with valves. your choice. the new ECM pumps are ~50-75% more electrically efficient compared to just one standard pump and will automagically handle zones opening and closing. Given the choice, I'd go with one of those and some decent zone valves.

3) pipe your header with extras now. easier to cap or valve them off than trying to undo lots of sweat copper or twisted black iron.

Other thoughts

Put as much effort and $$ as you can into reducing the heating load, especially if this is going to be a long-term house for you. Utility-sponsored deep retrofits are sometimes available, like the e-star pgm you mentioned. The cost-sharing can be pretty good. On an old house you can often cut the heating load nearly in half, and so cut down the size of the boiler by half (even a modcon). That reduces upfront costs, too, to say nothing of the long-term cost in saved fuel, better modulation / reduced cycling, etc. etc.

Check out this modcon self-install:

New Boiler Setup pictures by GEEVEE - Photobucket

which came in part out of this thread

http://forum.doityourself.com/boiler...ld-boiler.html
 
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Old 12-31-09, 09:26 PM
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Alright, great. Thanks to you, I think I have a better handle on things.

Happy New Year!

I know I'll have more questions in 2010.
 
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Old 01-02-10, 03:22 PM
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Yes, we'll do as much as we can up front, and we can certainly do more in 2010 before the next heating season.

Good advice on piping in the extras now. At this point, I'm planning on have at least 3 additional stubouts for additional future zones. But for now, I'll have one heating zone and one IWH zone.

The current piping for my old cast iron boiler is 1-1/4" copper feed pipe to cast iron radiators and 1-1/2" return pipe.

The feed and return connections to the Burnham ALP 150 is 1" and to Burnham AL70SL IWH is 3/4".

What would be the ideal header pipe size for my new setup? From some preliminary head loss calculations, I'm assuming that I could go with a 1" copper for the headers and pipe in some reducers to connect to the existing 1-1/4" feed and 1-1/2" return pipes? Or maybe bumping up 1-1/4" header pipes would simply the retrofit a bit?
 
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Old 01-03-10, 05:05 AM
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Despite the increased expense of a larger diameter, I'd go 1.25" on the header.

This article doesn't address your situation in particular, but there's some good principles about headers, etc.

Column - Plumbing and Mechanical
 
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Old 01-03-10, 06:55 AM
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Makes sense. I'll go with 1-1/4" copper for the header to minimize pressure drop across a shorter & fatter header.

Figure 4 in the latest link shows the the boiler loop as the primary loop because that's where the closely spaced Ts are located.

The Munchkin diagrams, on the other hand, show the closely spaced Ts on the header. So would the the boiler loop be a secondary loop piped off the header in this case?

Why is this so and under what circumstances would you go with either arrangement?

P.S. Sorry to everyone for all my typos. Wish there weren't a time limit on the edit function.
 

Last edited by Subieho; 01-03-10 at 07:01 AM. Reason: clarity
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Old 01-03-10, 07:13 AM
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The Siggy article is describing several different circumstances that address different needs.

In your case, you would pipe according to the manufacturer's I&O manual.
 
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Old 01-05-10, 10:27 PM
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Alright Xiphias -- after some more research it looks like I'm going with the Burnham Alpine 150 and a Triangle Tube SMART 60. With the lower head loss and higher flow , I can connect it directly to the boiler loop.

Near boiler connectons will be 1-1/4" copper piping all around.

I found Triangle Tube's installation manuals for their SMART tanks less than useful as they assume the use their boilers as well. Those interested in connecting a triangle tube indirect hot water tank to a low mass modcon boiler may want to check out Weil McLain's installation manual for their "own" indirect tanks.

http://www.weil-mclain.com/en/multim...ter_manual.pdf

Now all I need to do is figure out which heating circulator pump to buy as well as the zone valves and controllers for the heating loops.

Thanks again for all your help.
 
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Old 01-06-10, 05:44 AM
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That is a honking big boiler and likely far more than you really need.

Manual J heat loss is often a 10-30% overestimate. And any envelope improvements will drop the heat loss even more. And the design cold temperature is reached for literally only a few hours per year.

Save yourself a few grand now and every heating day in the future and go with the 105.

Thoughts on the other components later.
 
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Old 01-06-10, 09:07 AM
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Yes, I figure that the Alpine 150 is likely closer to 30% oversized.

I don't want to get too far adrift, but this decision is partially influenced by an intention to hook up another zone of baseboards in the carriage house at some point in the future, maybe an additional 300 sq. ft. of living space It would be a 20-ft. run of pipe underground from the boiler room out to that zone.

The carriage house currently uses hot water from the main house and an electric heat pump so it may make the most sense to convert the heating system to a high efficiency gas furnace out there.
 
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Old 01-06-10, 05:13 PM
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Attaching the cottage house load really takes this to a somewhat higher level. You'd probably want to isolate that loop with a flat-plate heat exchanger and use glycol in that loop for the outside run. All that for 300 sf of heated space doesn't seem worth it unless it is occupied year-round. Even then the design load is probably only 8000 BTU/hr or less.
 
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Old 01-06-10, 06:53 PM
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Originally Posted by xiphias
Attaching the cottage house load really takes this to a somewhat higher level.
I was afraid you'd say that. The carriage is a long term concern (and definitely worthy of a separate thread) as my parents and wife's parents are still very healthy. As such, I'd just pipe in a couple of stubouts on the manifold and leave that issue on the back burner for now?

I have no doubt that the old 285 MBU input/225 MBU output Weil McLain boiler falls under the sticky about being 99% oversized, in which case the Alpine 105 would be just fine, and I certainly get your point about design parameters being few and far between during a calendar year.

At this point, however, I'm just really thinking about the short term and trying to get this house up and running before the upcoming rental season. If there really weren't so much else that needs to be done, I'd spend all of our limited budget on new windows and insulation, and go with a smaller boiler.

Let's assume I did go with a the Alpine 105, I'd likely need to go with a larger indirect hot water heater because renters would require a bountiful supply of hot water. This is why I thought the Alpine 150 and a Smart 60 would be a fair compromise. What do you think?
 
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Old 01-06-10, 07:14 PM
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Domestic hot water in that situation should be figured as best as possible. Estimate what the dump loads are, what a potential continuous draw would be, etc. Then size the indirect and the boiler (if necessary) accordingly.

There are a number of calculators out there for this. One example is this:

http://www.comfort-calc.net/indirect_sizing.html

There are also ways to maximize hot water storage to gain some effective capacity. One method is to run the tank at 140F, and use an anti-scald tempering valve to provide ~115-120F at the fixtures.

So I probably shouldn't bring up solar domestic hot water, eh?
 
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Old 01-07-10, 08:48 PM
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I just returned from Jersey, and after a couple of hours in the crawl space, I'm sorry to report that the house is not plumbed for 1st floor and 2nd floor zones but rather front and back of the house loops. The bright side of things is that it makes my job at the moment a bit easier, and I have all the numbers to calculate for the heating loop pump. I look forward to hearing your suggestions after I do my calculations.

As for the indirect tank, I have to plan for the worst -- say a maximum of 10 people staying at this place, all of them showering after a day at the beach, a load of laundry going, etc...

Assuming that I stick with the Alpine 150, the interesting thing is that the first hour rating of Smart 50 indirect tank is on par with that of Burnham's 70-gallon tank (both at 180 F boiler temp and 70 degree rise).

The mixing valve is a good call, I'll definitely want to add one of those.

Solar is cool. Geothermal very cool. But yes, let's save that for another thread. I'm just beginning to wrap my brain around the basics of this stuff. It's amazing (and disappointing) to learn that it's taken all this time for folks in the trade to finally size things more appropriately.
 
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Old 01-31-10, 10:56 PM
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Resurrecting this thread. I just learned that I will not qualify for the state rebate program; therefore, I'll be moving ahead with the self installation.

Basic system info. is as follows:
- Burnham ALP150 Boiler with Taco 0014 boiler loop circulator
- Weil McLain 60 Ultra Plus Indirect Tank with Taco 0010 piped directly to boiler loop.
- 1 heating zone with Grundfos Alpa 15-55, (I'll be piping in some stub outs for future ad-ons)

I have one question about the wiring: I'll be using the boiler to control both boiler loop and heating loop circulators as suggested in the manual. Instructions also suggest controlling both circulators using a relay with 120 V coil such as Honeywell R4222.

But which one do I need and how are they wired?

R4222B 120 V General Purpose Relay w/ SPDT switching
R4222D 120 V General Purpose Relay w/ DPDT switching
R4222N 120 V General Purpose Relay w/ DPDT Pilot Duty switching

Here's the wiring diagram from the Installation Manual

Boiler :: Burnham Wiring picture by Subieho - Photobucket

On a less practical note, what exactly is this switch doing for the system?
 
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Old 02-01-10, 05:39 PM
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Why don't you qualify for the rebates? Who is your gas company?
 
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Old 02-02-10, 07:41 AM
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A prerequisite for the program is that all knob and tube wiring must be remediated for which the costs would be exorbitant. Hence, the savings of going through the state program would pale in comparison to the cost of the mandated work.
 
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Old 02-02-10, 05:56 PM
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I can't even begin to imagine how that relates to installing a boiler. Where did you see that information?
 
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Old 02-02-10, 06:23 PM
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It doesn't, not directly at least. FYI, the program I'm referring to is called Home Performance with Energy Star (HPES). An HPES contractor told me so. Because this program involves other services such as insulation and air sealing, I think the knob and tube may be a safety concern for those working in the attic. In any case, it would cost a small fortune to entirely redo the wiring.
 

Last edited by Subieho; 02-02-10 at 06:24 PM. Reason: typo
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Old 02-02-10, 06:45 PM
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You should qualify to the Warm Advantage program.

WARMAdvantage | NJ OCE Web Site

That will get you $300.

New Jersey Natural Gas :: The Save Green Project

That will get you an additional $900.

I didn't do anything but put a new boiler in and I got the $900 so far. I'm still waiting for the $300. Not sure why that's taking so long.
 
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Old 02-02-10, 06:59 PM
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Thanks for the links. I've seen both of these rebates but wonder whether I'm eligible for the $900 if I install the unit myself. It looks like a rebate on the equipment.

As you may already know, the HPES program provides a 50% rebate up to $10K on this type of work, if your gas consumption after the work is reduced by at least 25%.
 
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Old 02-02-10, 07:51 PM
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I'm not familiar with HPES.

If you have NJNG, call the people at the Save Green Project. They are easy to talk to and will tell you if you qualify or not. When I talked to them I already had my boiler installed. I didn't need to have the Energy audit down by a contractor to get the rebate. They sent someone from NJNG to check things out and ask a bunch of questions about the house. It was free and easy.
 
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Old 02-09-10, 02:07 PM
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Unfortunately, I'm in Atlantic County and, therefore, receive service from South Jersey Gas (SJG), which is not nearly as well organized in these matters as NJNG.

In fact, SJG is clueless in this regard. You're really lucky.

HPES stands for Home Performance with Energy Star and is available in many states.
 
 

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