Deciding between a new condensing boiler, or a FREE conventional boiler

alheim

Hi folks, long-time lurker, first-time poster.



The company I work with was involved with the Hurricane Sandy rebuild efforts in NYC - our plumbing department installed boilers into homes affected by the storm, and the gov't foot the bill. (The whole thing was a mess and we were lucky to just break even.)



Now, almost 2 years later, we have a whole pile (about 70) of unused, brand-new conventional boilers. Various sizes, various manufacturers. I can get one for free.



I just bought a real fixer-upper of a home that has no heating or piping of any kind (stolen while vacant), so I'm starting mostly from scratch. I will be combining existing cast-iron radiators on the second floor with radiant floor heat on the first floor. I think the return water will be well below 130 degrees due to oversized radiators.



Herein lies the dilemma: I would prefer a mod/con boiler (possibly a combi, likely Triangle Tube, Slant Fin, or Baxi), but that will run me at least $3,000 + installation (plus maintenance). Note that the condensing install is eligible for a $700 efficiency rebate from New York State. The conventional boiler would be free to me, and I'm sure I can manage a cheaper install as well.  I can also get a free water heater.



The home's load is roughly 45,000 BTU/hr on peak days. The home is less than 1,500 SF. I see myself living there for about 5 years, but who knows. The home is in a flood zone and could be hit by another "superstorm" if we're unlucky.



Is going condensing worth it in this case? Does the ~15% increase in AFUE account for the condensing boiler's ability to modulate?



..



P.S. if you are interested in learning more about the ~70 conventional boilers that we are selling for pennies, let me know. The models are about 2 years old and are available to all.

remodel

free

the prices seems right

Snowmelt

Hello

Do you have any steam boilers that are new

RobG

Free?

Free seems hard to beat. If it were me I would take the free boiler and use a Taco I Valve to mix it down and provide boiler protection with outdoor air reset. 60K btu's seems awful steep for a 1500 square foot structure. Are you sure about that?



And elevate the boiler as high as you can in case of future floods.





Rob

alheim

Yes

Several. What size? We are in NYC. Please send me a message.

alheim

Thanks

Noted. How would the Taco I-series mixing valve protect the boiler - by shutting it down if return water temperature is too low, to prevent condensing in a non-condensing boiler?



I was being extremely conservative with the 60,000 BTU number.  Looking at my Slant/Fin Heat Loss Explorer results again, it's really more like 45,000.  Sound better?  I updated my original post.  That's 30 BTU/hr/ft2.  The house is very old and is not very tight.

RobG

I Series

I'm not much of a typist so I will keep this short. The valve will mix the return water with the supply water to adjust the system temp to what is needed based on the outdoor air reset curve while allowing the boiler to operate off the aquastat setting (typically the max water temp the building requires).



See the link.

http://www.taco-hvac.com/uploads/FileLibrary/102-145.pdf



Rob

icesailor

Close to the Ocean:

My Northern British Isles genealogy got all excited when you spoke of a free boiler.

Some say it is a good idea to avoid direct vented Mod-Cons near the oceans due to airborne chlorides. Some high performance window manufacturers won't warranty their windows installed within some distance of the ocean. Over a mile. Some Mod-Con boiler manufacturers say the same or at least to not take the fresh air inlet from outside.

If you live in an area close to the shore, and you have times when you have high winds with no rain, and you have nights when the sparks are flying off the primary electrical wires on the power poles and sparks jumping off the transformers, I'd stick with the oil.

alheim

Thanks to all. Sizing & brands ...

Very interesting, the bit about mod/cons not being suitable for installation to close to the sea.  We'll call that the straw that broke the mod/con's back, because the more I think about it, the more I like the idea of a free conventional boiler.





The home is about 1,500 SF with a heat loss of roughly 45,000 BTU/hr on peak days.  The smallest units that I can get my hands on (for free) are the following:



Crown 'Aruba 3' Boiler Model AWI061S; 61,000 Input; 50,000 DOE Heating Capacity, 43,000 I=B=R Net Rating (Water), 80.0% AFUE



Weil-McLain CGa-3 Boiler; 70,000 Input; 59,000 DOE Heating Capacity, 51,000 I=B=R Net Rating (Water), 84.0% AFUE



Burnham ES2 Series Model ES23 Boiler; 70,000 Input; 59,000 DOE Heating Capacity, 51,000 I=B=R Net Rating (Water), 85.0% AFUE





The boiler will be in unheated / semi-heated spaced (an enclosed drafty basement).



Using the IBR Rating, it looks like I could go with either the Weil-McLain or the Burnham. Thoughts? Opinions on these brands & models?



I think that the Burham is the nicest unit, and the Crown is the cheapest.

icesailor

Taco 4-Way "I" Series:

Actually, there is a sensor with DIP switches that are part of the valve, Regardless of what the high limit is on the boiler, or how low the ODR has re-set the secondary water, the valve keeps the primary water from coming in to the valve to mix until the boiler temperature is above the set point of the DIP switch settings. 120 Degrees for Gas or 140 Degrees for oil. The bigger the system, the greater the volume of water in the system, the better the valve works.



In the real world of cheap, they can be a tough sell. But if you are trying to replace a large system with a small hot rod high efficiency boiler, and do P/S, IMO, there's no better way to marry the unknown system, the old, with the new. Especially in a converted gravity system. A circulator run on ODR will sooner or later make every radiator or heat emitter in the house be the same temperature. No more "The radiator above the boiler is so hot you can fry an egg on it but the radiators in the back of the house are ice cold. If the ODR says 120 degree system water, sooner or later, the whole entire system will be 120 degrees. Isn't that the ultimate goal of constant circulation?

IMO.

alheim

Hello again.

I was wondering if anyone has an opinion between these three units:

Crown 'Aruba 3' Boiler Model AWI061S; 61,000 Input; 50,000 DOE Heating Capacity, 43,000 I=B=R Net Rating (Water), 80.0% AFUE

Weil-McLain CGa-3 Boiler; 70,000 Input; 59,000 DOE Heating Capacity, 51,000 I=B=R Net Rating (Water), 84.0% AFUE

Burnham ES2 Series Model ES23 Boiler; 70,000 Input; 59,000 DOE Heating Capacity, 51,000 I=B=R Net Rating (Water), 85.0% AFUE

The home is about 1,500 SF with a heat loss of roughly 45,000 BTU/hr on peak days.

Cheers
Alex

Rich_49

BURNHAM .
The 4 way valve basically makes 2 mixed temps . One back to the boiler and the other out to the system . All supply and return water passes through this valve so it gains control of everything that leaves it in any direction

icesailor

@Rich:

Except that the Taco "I" Series 4-way is a FB Valve. It does all that spooky stuff all by itself with no help from anything else.

On a big converted gravity system, the first time you run it, it seems like FM. The first one I installed, they were running 170 degree water and the middle of the house was so hot they opened windows, The ends needed electric heaters. Once the "I" valve was installed and working, on a 15 degree OAT, the valve was running 125 degree water and the whole house was the same temperature. Every radiator in the system was the same temperature. The only other thing I added was just a standard 3 speed circulator on the secondary side. #2 speed kept up with it.

Did they save any money?

alheim

I went with the Burnham ES2-3.



I pretty much understand the operation of the Taco 4-way valve, thank you. How would this work if I installed the optional Outdoor Reset on my boiler? Installing the ODR will vary the supply water temp as required, leaving the Taco 4-way with the sole job of protecting the boiler from cold return water temperature, yes? Or would it still have a role in keeping every radiator in the system at the same temperature?

Alex

alheim

I should post a schematic of my intended system for criticism.

Rich_49

You would no longer need the I Valve . The purpose it served on the cast iron boiler is not required with this boiler . Just keep the return water temps above 110* as per manufacturer