May need to replace boiler – What with?

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Dana

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You went through 10 Grundfos pumps in 28 years? Sounds like iron-impeller pump on the potable side or something?

Polaris has a pretty good track record overall, but I don't have a lot of direct experience with them. (Ping BadgerBoilerMN on this- he posts here frequently, and has done quite a few heating systems based on Polaris HW heaters.)

There's little downside to oversizing the heat exchanger other than a bit of pumping power. Since they are fully counter-flow the delta-T between the potable & system side (sometimes called the "approach" temperature) doesn't have to be much- most are BTU-rated at a 10F difference. But installing one rated for 2x or even 3x the BTU rate cuts that difference by quite a bit, and may even be more inline with your actual radiation flows. I suspect (but don't know without doing the full analysis on the actual pump and pumping heads of each zone) with one zone valve open you're getting at least 2-3gpm of flow and with all of them open you may be getting 8-10gpm. See the BTU rate & min-flow requirements of this series.
 

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Dana,
How do I Ping BadgeBoilerMN?
Do you know anything about the Phoenix Water heater?

Send him a private message using the service on this site. Or you could email him. He's done more than a few of these- this pic is from his company site:

hotwater_PolarisFinal.jpg


(The green blob is the Taco "X-Pump Block" heat-exchanger/pump unit, which is a pricey way to get there, with more features than you'll likely need or want.)

The Phoenix water heaters are great units with modulating burners, but way overkill for your loads. There's no point to a modulating unit that in an application where would literally never exceed it's minimum 40 KBTU/hr firing rate. Your space heating load is half that, and with 119 gallons of thermal mass you'll never draw down the hot water to the point where it would need to ramp up either, unless you LITERALLY showered for hours at a time.
 

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I did not realize yet that the Polaris was a modulating unit. That makes it even better. However that is the fact that the house only cost $160 per year to heat and $192 for all the rest of the gas for the year. However, so far, I do not see a lower price reasonable system that is better than the Polaris. People just do not have house that uses this little energy. The current Heatmaker keeps pretty warm year aroung, but always 190 + in winter. As I see it most of the “real” solar type houses the people for the most part will spend anything to save a drop of oil or gas, without much thought. It is all show. I just want a reliable system that works well and last for many years. That does not mean it need to be the lowest cost thing either.

As for putting a system like this, I need to understand the design of what goes in the house. That is an interesting picture from badgerboilerMN. I sent him a message, not too sure if it went out. I will try an e-mail next.
 

Dana

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The Polaris does NOT have a modulating burner.- the Phoenix does.

The Vertex is quite a bit cheaper than the Polaris and in many ways nearly identical. But not being stainless, the anticipated lifespan is probably more like 12-15 years compared to 20+ for the Polaris.
 

Heating in Colorado

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Dana
Is that an advantage of the Polaris having a modulating burner in my system? Both are Stainless, but a different kind of stainless,is one better with the temperature and water contact? I like the expected longer life. I am still leaning toward the Polaris, but can consider the Phoenix.

I have had the Heatmaker for 28 years this month. Most repairs were done by me and they were simple part swaps. I did try a couple contractors replacing those circ pumps but with no added benefit in lifespan and more than triple the cost. I soon gave up on that and just swapped when it began making the noise of the failed bearings. Yes, they were cast iron, what would have been better?

I need to begin looking at the total layout of the new system as a possibility too. Is Taco Flo Pro University a good place to look?
 
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Dana

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As I said in a previous post, there's no point to have a modulating burner that never modulates. At your loads you will rarely or never exceed the min-fire output of the Phoenix, rendering it's ability to modulate moot. Were it's min-modulation 10,000 BTU hr there could be some advantage in your situation depending on how you set it all up, but not at (it's actual) 40,000 BTU/hr min-fire. It's a great unit- for somebody else/some other application.

When pumping potable water you need to use a bronze or stainless types. Most of the Taco circulators have bronze or stainless versions, with compatible impeller cartridges. Fresh water has lots of oxygen in it, causing iron pumps to rust. If it's all on the closed system, with no fresh water coming in, the iron pumps should last for a good 20 years or more if properly specified for the application.

I've never looked at the Taco Flo Pro University stuff, but it has to be better than a WAG, eh?
 

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Dana,
I have been looking at the Panel Radiators previously mentioned. So far, I have only looked at Pexsupply, which carries Buderus. Looking at the specks of them, they state the BTUH different temperature on the Buderus web site. As you know, I expect I will be running this system at 140 or 150. If I replace a 3’ SlantFin with a 2 ½” thick Buderus Model 21 36” unit operating at 140F water the removed unit output was 960 BTUH, the inserted unit output a 12” height would be 1400 BTUH for a gain of 540 BTUH for $360, Monetarily, it certainly pays to put in both taller and wider unit per BTUH by far. Today’s cost goes down from 3.77 BTUH/$ to 6.58 BTU/$. With the wider Bederus being 4”, their narrower at 2 ½” and the current Slant Fin at 2 ½”.The Model 22 24” x 36” x 4” would give me a 2140 BTUH gain in the room with the greatest shortage. The other two rooms can each have an additional 1300 BTUH added the same way. It appears to be a good fit. Will this work okay with a one pipe system in series with the other slant fin radiation? I will continue to look at additional brands. I am unsure of which brand may be better quality
 
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