Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

New Boiler Proposed By Contractor- What Info Should I Know?

Options
Sorta
Sorta Member Posts: 46
Hi all. Thanks for reading.

A local HVAC company came out and recommended that I purchase a new boiler from them. I'd like to make sure I'm making the best decision, but am not sure of what I should know, what important questions I should ask, etc. Are there things I should be asking, or having them answer? I tried searching through the forum threads to read-up on things.

Like how do I know that the boiler that they recommend is the best "match" for my house & needs? They gave me a north of $10k proposal for a high efficiency Bosch Greenstar 131 heating only model / and installation. My current boiler is high-efficiency, and I do know I'd like a 95% high efficiency boiler. The contractor said Bosch is the only high-efficiency they offer.

Many questions in my head. Like, how do I know the recommended boiler is the best for me? Is the price-area (not specific, as I know the forum doesn't talk about specific prices due to price-fixing!) something that makes sense for a new installation? I'm in downstate New York.

This might be a dumb question, but are are there contractors that I can find that just will install a boiler, the piping needed, etc...if I purchase the boiler separately? Can I even buy a boiler separately, or do I have to purchase one from the contractor who will also be installing it?

Well, thank you very much for reading this and for your replies. Thanks for informing!





Mad Dog_2
«1

Comments

  • kcopp
    kcopp Member Posts: 4,449
    Options
    Why are you looking to replace? What wrong w/ your current set up?
    Yes price is dependent on area.
    Most all contractors will not install a unit someone else purchased.
    You purchasing a set up that the installer knows well. They will be the ones who will service it when/ if there is an issue...
    Mad Dog_2
  • Gilmorrie
    Gilmorrie Member Posts: 185
    Options
    I would highly recommend buying the boiler, including installation, from one single contractor. Otherwise, you may be in the middle of a warranty dispute. I would check references, for sure. What is the size of the boiler and how did the prospective contractor come up with it?

    High-efficiency, wall hanging units often require proprietary replacement parts and factory trained service providers. I sense that you are not a DIYer, but that's fine.
    Mad Dog_2
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,169
    Options
    Bosch Greenstar is a quality product. I worked with them for a short time. Tech support is average to better than average. On a scale of 1 to 10 where 10 is the best I would rate them about a 7-8. Can't say anything about post Covid manufacturing but when I was in business they had a great product. Is it the best for you? That depends. If you have a high mass system (Cast iron radiators) or radiant floor heat where the return water system temperature can be lower, then you will get the benefit of the condensing boiler ultra High efficiency.

    If you have a higher temperature system like Copper tube/Aluminum fin baseboard, then the condensing feature of the boiler will not be as efficient because of the higher return water temps. That is a lot of extra feature as a higher price that you wont get the benefit of.

    Tell us more about why you need/want a new boiler?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Mad Dog_2
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
    edited March 2023
    Options
    Think 5 digits for price. I doubt purchasing it yourself would save any money, likely the opposite. I’d consider sizing too - the Bosch’s minimum fire is pretty high: the 131’s minimum input is 36,000btu/h and the two smaller versions minimum input is 24,000btu/h. If your heat loss fits the an 80,000 Btu/h boiler, then other manufacturers offer models that go all the way down to 8,000 btu/h, as 10:1 turndown is common. This provides longer run times, more condensing and more consistent indoor temps. How much propane/gas did you burn last year? And was it propane or gas? 
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,169
    edited March 2023
    Options
    I can't help myself. After looking at the OP's screen name I have to ask if someone could rename this post:

    New Boiler Proposed By Contractor- What Sorta' Info Should I Know?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Mad Dog_2Sortaron
  • Sorta
    Sorta Member Posts: 46
    Options
    Great responses & thank you all for them. These really help me.

    - So really...I don't WANT a new boiler. But was told due to "mud" being in it, that mine is probably coming to an end soon. (?)

    It started when I mistakenly allowed air to enter in to my system, and couldn't get the heat back on in some zones. So I called the local HVAC contractor. They cleared the air from the zones and heat returned. But then the technician said he thinks there is a lot of "mud" in the system, and given the age of the system (I'm guessing it's about 20 years old. It is at least 16 y/o), he said they wouldn't be willing to clean it. But they could offer a new boiler.

    Further, as the tech was finishing-up there was a large pressure increase (past 60psi) and the tech said he thought the water fill valve must have failed. So he worked to get the pressure where he said it was okay, then he manually turned-off the fill-water line. He left, and an hour later I noticed no heat in any rooms. The boiler had stopped, the pressure was down to 10 psi, and a water pressure error code was showing. But when I turned the fill-water line back to open...the boiler started back up and heat returned. But so did the high pressure. It is currently at 60+psi.

    So...I was thinking, why does this mean I need a whole new boiler? What if I purchased & installed a new water regulator/auto-fill? If the tech says it failed, wouldn't it be logical to think a new one would work? Instead of a full flow of water entering the boiler (like it is now), it would limit the amount only the boiler needed it? And a new water fill valve is like $90.

    - Thanks for the price range info. Gives me a better feeling of what to expect.

    - Thank you for the info that in general it is a good idea to buy the boiler from the same contractor who installs it (due to familiarity, knowledge, proprietary parts, etc).

    - I really have no idea of the btu information. I know zilch about this. So, when you mention the input, etc...it's like a foreign language to me. I'm not sure how to address.

    - I DO have copper tube/Aluminum fin baseboard in the house.

    Thank you again everyone.
    Mad Dog_2
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
    edited March 2023
    Options
    Gotcha - sounds like you found the exact wrong company to install a new boiler. That’s good news! You caught it before spending a bunch of money. On to the next one. 
    Mad Dog_2STEVEusaPASuperTech
  • Sorta
    Sorta Member Posts: 46
    Options
    Hi Hot_water_fan. One of the biggest things that stinks when you are dealing with HVAC contractors or auto mechanics, etc...is that I get the feeling that I'm being pushed to purchase the most expensive item, etc. Hey, I realize that knowledge is power and worth paying for. And that HVAC companies & techs go to school, and really know their stuff. But there is always that question in my head "Are they upselling me to upsell me? Or are they doing it because they really think I need this & it is the most cost effective solution?" It's frustrating. But that's why I'm grateful for your help and the others here.

    I guess there are other HVAC contractors in the area. This particular one we've been using for over a decade and they are nice people, but...well maybe second opinions would be warranted. The thing that stinks is that just having an HVAC tech over from another company to the house costs $120.

    And I'm worried about the high 60+ PSI in the boiler currently. I was told it shouldn't ever go above 30psi, and usually operates at 20psi. I'm not quite sure how to go about fixing it, except my idea above about replacing the auto-fill valve.
  • kcopp
    kcopp Member Posts: 4,449
    Options
    I guess some pix would help.... If the system had mud in it, it can be flushed out. Approx where are you? A county location would be fine.
    Mad Dog_2
  • Sorta
    Sorta Member Posts: 46
    Options
    I'm in Orange County NY. The "mud", is that the same thing as boiler sludge? Just never heard the term mud used for boilers. Also, the tech was nice and tried explaining things to me. And he did mention there is a chemical additive that can be circulated to clear out "mud". But then he said I would have to install a new valve, or something-or-other, in order to do this. Below is the system:


  • JUGHNE
    JUGHNE Member Posts: 11,109
    Options
    Is that a "Munchkin" Boiler?

    You could shut off the power and loosen the two screws in the lower front panel and remove the top.

    The product tag would be perhaps on the left side on a steel flap. Picture is good.

    Then inside on the upper right is a pop off relief valve, it should have a tag stating 30 PSI. Picture again.

    If you truly had 60 PSI in the boiler that relief valve should be peeing all over your floor, assuming it is piped correctly.

    The grey expansion tank has an air valve under a plastic cap, remove the cap and depress the air valve just to see if water comes out.

    Your auto fill valve is near that. Pictures also.

    If either of these things fail you could replace them and use those items for a new boiler if it come to that.
    They do not come with a boiler and are accessories added as boiler is installed. You could show a new boiler installer your receipts and if they would not reuse them I would send them away.

    How many feet of baseboard heaters do you have in the house?
    Mad Dog_2
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
    Options
    I’m less concerned about the cost, it’ll be expensive either way. Possibly more, because you’ll be hiring someone with better skills. It’s more concerning you’re losing pressure in a closed system - that implies a leak and shutting off the makeup water doesn’t fix that - fortunately the boiler shut itself off before something bad happened. Adding makeup water frequently causes its own set of issues as well - like corrosion. 
    Mad Dog_2
  • Sorta
    Sorta Member Posts: 46
    Options
    Thanks Jughne and Hot_water-fan!

    Jughne, yes it is a Munchkin. I has served us pretty well over the years. I see now on the label below it was made in 2005. I took the photos you requested (I hope I did..). I also included a photo of the pressure gauge. I remember now that the technician did say that he thinks that the relief valve is "probably very corroded. That's why it isn't opening and releasing water at this high pressure". But the condensate drip line is pumping out steam.

    I just measured the entire house and there is a 236 feet, 5 inches of baseboard.

    Hot_water-fan, the closed system info is interesting. So you mention a leak of some sort. I do know that there was/is a drip coming from the red handle of the hose faucet (on the right "out" vertical pipe). I saw puddle of water there this morning. I tried tightening it as much as possible and think it may have stopped.





    Mad Dog_2
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,840
    Options
    @Sorta Have you checked find a contractor on this site? I would call @JohnNY you can PM him
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,250
    edited March 2023
    Options
    Yeah  I wouldn't make another move until you  get an independent professional consultation to know EXACTLY what the issues are how  to best address them.   You'll find the best minds in the business here at The Wall  Mad Dog 
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,250
    Options
    The tech you had out there was a meatball .
    Whenever you have a pressure issue on a HW system, you can't just make a quick adjustment, shut the feeder valve and walk away.  A caring and experienced heating pro would not do that.  Mud?  Guys call things different names, but he sounded like he cranking you like an organ grinders 🐒 Monkey...for lotsa change.  You might very well just need. A new feeder valve, Relief and Expansion tank swap which I almost always do since the system is dropped anyway.  Mad Dog
    flat_twindavidd
  • hot_rod
    hot_rod Member Posts: 22,486
    Options
    A testimony to how those Munchkins could run even improperly piped. Looks like a start of primary secondary, but I don’t see the second pump, and the closely spaced tees has a partially opened ball valve? Maybe the is piping we don’t see?

    How often has it been opened and cleaned? Is it not running properly now?
    I suspect that pressure gauge may not be accurate.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Mad Dog_2kcoppdavidd
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,250
    Options
    Munchkins sure got a bad rap back then but my fellow Long Islander Mike The Army of One  Jablonski loves them and has dozens of them running for 20 years   mad dog
  • hot_rod
    hot_rod Member Posts: 22,486
    edited March 2023
    Options
    Mad Dog_2 said:

    Munchkins sure got a bad rap back then but my fellow Long Islander Mike The Army of One  Jablonski loves them and has dozens of them running for 20 years   mad dog

    Parts of the learning curve were the piping, service, and control.

    That Gianomi (sp)coil heat exchange is still used in many mod cons, now called Sermeta 30 million have been produced. I prefer it to the fire tube design.

    https://sermeta.com/en-us/

    https://www.youtube.com/watch?v=uQw7mBLz5r4
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Mad Dog_2
  • JUGHNE
    JUGHNE Member Posts: 11,109
    Options
    Steam coming out of the condensate drip line is a concern.

    Tech should have shut the boiler down if he could not get the pressure relief (pop off) valve to pass water.

    With the boiler off and cool, and with some pressure in it, (you can open the drain valve carefully to see if any pressure is in the boiler) does water continue to drip out of the condensate line. Put a bucket under it to monitor.

    There should be no water coming out of the drain an hour or so after firing.

    If so then your heat exchanger could be leaking water inside the boiler.....end of that boiler.
    Mad Dog_2
  • Sorta
    Sorta Member Posts: 46
    Options
    Thank you all again for great insights & help.

    Ebebratt and MadDog, I didn't quite realize that HeatingHelp also had contractors listed for contact. I'm really happy to see this. I will try to use it as best I can. And I'll contact JohnNY as a start. I'll have to see if he is in my area.

    Hot-rod, it was cleaned a few months ago by the same contracting service. It is in generally good shape, IMO. Every once in awhile a zone vale motor or head need replacing. But as of right now, it is running...but at the high pressure you see in the photo of the pressure gauge. The temperature part of the gauge seems to be working pretty well, as it seems to match what the digital read-out says on the panel. Could the PSI portion be malfunctioning? Should i get a new gauge?

    Jughne, thank you for this information. In your instructions, you say "you can open the drain valve carefully". Which one is the "drain valve"? When I turn off the boiler, the boiler pressure eventually drops down to a little above 10psi. I shut it off last night and this morning, the pressure was about 10psi.
    Mad Dog_2
  • hot_rod
    hot_rod Member Posts: 22,486
    Options
    holding pressure is a good sign, is the brown fill valve open or closed?

    Shutting off a couple of those yellow valves would allow you to easily change the gauge. If you get the size thread size it would be a quick switch.

    A hose bib gauge like this could screw onto this valve. A 0- 30 psi range, for a temporary.

    No leaks and it's running, recently cleaned and adjusted. Let 'er run./
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Mad Dog_2
  • Sorta
    Sorta Member Posts: 46
    Options
    Thanks hot_rod. The brown fill-valve on the feed water regulator is currently pointing down. Prior to yesterday, before the tech told me he thought it is broken, I was able to manually push it up and when it got to as far as it could go...I'd hear water running. Same thing when I manually pushed the lever as far down as it could go. But I just now tried doing both, and at both up and down extremes..I do not hear it activating any fill water.

    Regarding the holding of pressure. Do you mean that even if the pressure stays at the very high 60+psi...that is a good sign?

    Good idea about using a screw-on hose gauge. I'm pretty sure I have one of those to use. I'll see if I can find it and add it at that drain in the close-up photo you provided. Thanks again.
    Mad Dog_2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,250
    Options
    Years ago, Jeff Cook ran Munchkin. Met him with timmie Mac.  Great guy.  Chuck Shaw was with tech support w them for several years  another great smart guy i miss.  Yes, you can't go wrong with the Guys from here (Dan's & Erins Dugout).  Mad Dog 
  • catastrophy
    catastrophy Member Posts: 8
    Options
    Arent these water fill valves adjustable?
  • clammy
    clammy Member Posts: 3,114
    Options
    Just wondering is your Hvac contractor worthy right ? Have they been servicing the boiler and are they the one who had installed it ? As for the boilers pressure gauge reading did they verify this reading by checking w another gauge at a boiler drain ? If so then they should have checked the fill valve for proper operation also checked and replace the safety valve which should have blown off , while at it also check expansion tank .The fill valve looks like a standard iron body fill so I would image it clogged w rust . Did the service mech open the boiler up and check the combustion chamber or did they just look and suggest replacement .
    At about 23 years of service it getting close to replacement . I would suggest if the system is supposedly clogged w mud what is there suggestion for removal and cleaning of the system ? If they have no answers for you then you have a idea of what you will be getting from them aside from a new boiler zippo .
    Where’s this mud coming from ? Maybe get a answer for that like I said there’s leaks ? Buried heat loops ?
    You should be asking what are they going to do to bring the quality of your water your filling the boiler with to what the manufactures specs for fill water chlorides ,calcium limes and tds . It’s important for warranty extremely hard water is not good for a boiler which contain very little water . They should also be adding a inhibitors and o2 savanges treatment to protect the boilers heat exchanger . Another question are they going to install condensate neutralizer for the boilers condensate drain it common practice and code in most areas and done by most professionals . I would also be asking what they are doing for make up water treatment . They should be installing a demineralizing make up water filter . If your system has mud and debris in it aside from draining ,purging power flushing and adding treatment a good magnetic dirt separator would be in order . If they look at you w no answers please by all means show them to the door in which they entered because they are clue less and are ac installers not hydronic heating guys.
    I have worked in Orange County in the past a lot and now occasionally and have seen what goes on in the Wild West and as for the workmanship and quality of contractors like the tides it’s got some real high and lows . A lot of cut rate stuff but heck they know no better and just do what they know repeating over and over and always for less then dirt . . At a 199 how many sq ft I see the home and when was it built . Is it also do your hot water ?
    As for you purchasing and them installing just remember it will be your problem not there’s when issues arise being they just installed . I would image there’s no chimney hence the direct vent mod con . If there’s is a chimney possibly look into a standard cast iron boiler and maybe you have to get your chimney lined .The life spanning of a cast will be longer then any mod con and not that they don’t require maintenance it’s not as required as a mod con and most parts for them are pretty off the shelves there also more forgiving on the install as compared to a mod con .
    Being your system is baseboard it’s a hi temp system u less specifically designed to use baseboard at a low temp meaning more baseboard then required a mod con is sort of a mis match being there rated eff it can only achieved that w constant return temp below about 120 slim chance it was designed w that in mind.
    Not to confuse you but there’s a lot to replacing a boiler and when it done correctly by a professional who is familiar w hydronic heating it all get replaced no bits and piece work to save a couple of bucks cause whenever the parts that didn’t get replaced go you paying more to have them replaced ,just common sense .
    It s like buying a new car who wants a new car w your trade in tires on it ?
    Make sure they are going to replace everything zones valves pumps ,backflow ,prv and expansion tank ,maybe possible install a zone valve control instead of a birds neat of wire nuts that doesn’t look quite professional and every time a service person goes there they look at it and don’t want to touch it in fear of spending 20 minuites tracing wire should and re doing wire nuts that ok he s going to add that time to your bill . Ask questions and if they have no answers well that’s telling you something .

    Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
    Sorta
  • clammy
    clammy Member Posts: 3,114
    Options
    I loved clogged w mud , won’t open boiler to clean but we can sell you a new boiler. They sound like a awesome bunch best advice is look else where . Unless they got some answers . Also north of 10 k for a complete replacement is low in my book for that size boiler w what is considered a proper replacement ,but heck what do I know .lol
    Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • Sorta
    Sorta Member Posts: 46
    Options
    Hi clammy. Wow, thank you for such a helpful and informative reply. The service tech did not open the boiler up & check the combustion chamber. They just suggested replacement. They said the company wouldn't want to spend the tech's time to open up, clean out the mud. Which struck me as a little odd. They did not verify the pressure with another gauge. They didn't do the other things you asked either. In their defense, they came out last minute, late in the day & the tech stayed late. He did clear the air-bound lines, and only at the end did the pressure issue & mud issue arise. If he stayed, it would have been well into the night. But they didn't offer to come back to fix/resolve the issues, just to replace the boiler.
  • hot_rod
    hot_rod Member Posts: 22,486
    Options
    On the service techs defense, putting your name or company name on a boiler that old, most all repair parts are parts obsolete, is risky.

    If you spent $$ to have it flushed, cleaned, re-calibrated and the microprocessor failed shortly after. Did they do a service or dis-service? It could be a company policy to not spend time and money on a particular brand or vintage boiler?

    My policy was two bids, rework the old and offer a replacement.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • clammy
    clammy Member Posts: 3,114
    edited March 2023
    Options
    To be clear did he mean mud in the systems water or in the combustion chamber ? I wonder because if they recently did service the heat exchanger should be fairly clean one would think . If your boiler water side heat exchangers was loaded w mud I think your boiler wouldn’t be cycling on on of a few codes including the pro lock out on low pressure being that tiny 1/4 pressure switch connection commonly get clogged especially if your system has mud in it or cycle on its limit due to poor heat exchange due to mud in the water side . I too know many who would not open a vintage munchkin at 20 year special old . Does your system contain any radiant heating by any chance ? Also I see your home on city or well water ,I know Orange County does have a fair amount of iron in most of the well water from what I ve seen but mud build up usually comes from iron piping or From possibly a slow leak and make up water over time . One thing for sure at 60 psi that pressure isn’t doing nothing to keep it going aside from excessive pressure on a o ring banded inlet and outlet assembly on the boiler so at that
    pressure I would think the o ring may start to fail and weep . The tech may have been speaking for himself and not wanted to attempt to get the mud out I would think
    Peace and goodness luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • hot_rod
    hot_rod Member Posts: 22,486
    Options
    Mud is a relative term. All boilers will discharge red, brown, black water when you first start draining them. It is the ferrous metals inn them system corroding.

    If the "mud" layers several inches in the bottom of a bucket....

    That could indicate a leak causing frequent make up water, or
    non barrier tube in the piping, Pex, Rubber tube, etc.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Sorta
    Sorta Member Posts: 46
    Options
    Thank you all for your help again. I've re-read through your help and suggestions. And one thing was to do a "heat loss calculation" (or is it "heat load")? I've downloaded the Slant Fin app, but have run in to some things I have to ask about it:

    - Ceilings: Do I put the ceiling measurements anywhere (those ceilings on the floor where the other side of the ceiling is the attic, or roof in the cases of cathedral ceilings)? The app seems to only ask about ceilings once, under "Ceiling Factor".
    - Cathedral ceilings: A few rooms have cathedral ceilings. For these rooms, how fill-in the "Room Height" question?
    - Indoor Temperature / Outdoor Temperature sections: How do I fill these out? Do I have to find particular info about my area, etc. for outdoor temp to use? And what about indoor? Just use like any constant, for ex. 70 degrees F?

    Thank you all.
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
    edited March 2023
    Options
    In this situation, given that you said above you want a high efficiency boiler, you can skip the heat loss- you know the linear ft of baseboard, that’s a ceiling to boiler size. From there, given that you said you wanted a modcon, you have basically the 150kbtu/h boilers to choose from: many of these have 10:1 turn down ratio, so shouldn’t be oversized. Think of turn down ratio as a newer stove: some burners are sized for simmering, some are for boiling. The selling point of the modulating boilers is you can precisely match your load (which is linear, increasing as outdoor temps decrease) to your boiler output. If done perfectly, your boiler could turn on in October and off in March. It won’t work out like that, but that’s the idea. The thinking is that a. It’s most efficient and b. It keeps indoor temps the most consistent. 

    You can try this quick method: https://www.greenbuildingadvisor.com/article/replacing-a-furnace-or-boiler. But we’re talking very minor refinements from this point, probably nothing you’ll notice. Modulating boilers, especially in this size range, cover up a lot of sizing mistakes. If your home was smaller and you wanted a single output boiler, there might be some value to the heat loss.  
    Sorta
  • Sorta
    Sorta Member Posts: 46
    Options
    Thank you greatly, Hot_water-fan. From comments in this thread, and then googling a little about it...I learned it "might not" be buying a high efficiency mod-con boiler, because we have copper piping? Something like the copper doesn't cool the water enough on the return, which some how a mod-con needs to actually be "efficient"? (Really, I'm confused on this).

    I wanted a high efficiency mod-con because, well...that's what we had in the Munchkin. But if the copper pies "negate" the efficiency-aspect of the mod-con, would a standard boiler be just a good?
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
    Options
    The copper pipes are unrelated. Baseboard uses higher temperatures than some other emitters, but that just means you won’t condense on the very coldest days - not a big deal! You’ll condense the rest of the winter. Try that quick fuel usage calc and we can try to nail down a % or just guesstimate that you’ll condense 75-95% of the time. 
  • hot_rod
    hot_rod Member Posts: 22,486
    Options
    A cast boiler, fixed output probably runs more in the mid to high 70% efficiency when you calculate run time cycle efficiencies. Only at steady state will they get into those 80% numbers.

    So a mod con, even when it is not condensing probably still maintained mid 80 to high 80%. The modulation takes much of the cycling out and possibly 50% of the season you could condense and get into 90%.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Sorta
    Sorta Member Posts: 46
    edited March 2023
    Options
    Hot_water_fan, I went to the greenbuildingadvisor site and started gathering the information needed to do the calculation. But, as far as I can tell, nowhere on my boiler does it list the output BTU/h rating. It does show the input BTU/h rating = 199,000.

    But no output BTU/h rating. The boiler is a Munchkin 199M. Any insight as to what the output rating would be for my boiler? Thank you.

    UPDATE: I found a Munchkin brochure here https://tjsradiantheat.com/assets/Munchkin-Boiler-Brochure.pdf that shows the Munchkin 199m boiler "D.O.E. Rating" as "61,000 to 183,000".

    I've read that D.O.E. is another term for gross output rating. But a range? Don't know what number to use in the heat load calculation for the output rating.
  • hot_rod
    hot_rod Member Posts: 22,486
    Options
    That boiler can modulate from 61- 183,000 btu/ hr.

    The load calculation should end up showing you a load at design day. The boiler needs to size to that number. A sizzle or two larger than you need. As suggested, a 150,000 would be adequate
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
    Options
    @Sorta that's just trying to get an efficiency. You can use 92% - 183/199. If anything, that'll be conservative.
  • Sorta
    Sorta Member Posts: 46
    Options
    Hi Hot_water_fan. Thanks for your reply & help. I worked through the steps/calculation from the greenbuilding site you provided a link to. I used the high-end of the D.O.E. range 183,000 for that part of the calculation. Since it asked for "Max output", i figured I should use the maximum of the range. Below is what I did.

    Does the below look correctly done? And what do the results indicate..that I only need a boiler that does 79,106 - 86,608 BTU/hr ?

    -----------------------------------------------------------------

    Heat Load Calculation: using Jan-Feb statement (1/19/23-02/16/23)
    input rating of 199,000 BTU/h
    output rating of BTU/h (from 63,000 to 183,000 btu/ hr)

    99% outdoor dry bulb = 9
    225.8 therms x (183,000 / 199,000) = 207.64 therms x 100,000 = 20,764,522.62 million BTU (MMBTU) aka 20.76 million BTU (MMBTU)
    HDD 65: 857.3
    HDD 60: 713.3

    HDD 65: 20.76 MMBTU / 857.3 = 24,221 BTU per degree day. Divided by 24 hrs = 1,009 BTU per degree hour
    HDD 60: 20.76 MMBTU / 713.3 = 29,104 BTU per degree day. Divided by 24 hrs = 1,213 BTU per degree hour

    HDD 65:65 degree minus 9 99% design. Implied heat load: 56 degree x 1,009 BTU per degree hour
    = 56,504 BTU/hr

    HDD 60 degree:60 degree minus 9 99% design. Implied heat load: 51 degree x 1,213 BTU per degree hour
    = 61,863 BTU/hr

    For sizing the equipment, use the ASHRAE 1.4x sizing factor:
    1.4 x 56,504 BTU/hr = 79,106 BTU/hr (with a 65°F balance point assumption)
    1.4 x 61,863 BTU/hr = 86,608 BTU/hr (with a 60°F balance point assumption)