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How to approach purchasing a boiler for a historic/old property

kamelkev Member Posts: 9
edited September 2021 in Gas Heating

Bought a craftsman from 1902 in Denver. Has a boiler from ~1950 in the basement. I think it says 160mbh on it. Contains asbestos. There are also asbestos covered pipes to and from the unit.

There are two units here, each with a zone valve. Both valves are bad. One is entirely stuck closed, the other one works if I mess with it.

Has what I would guess is an undersized taco pump, which screams very loudly when on. I happened to find a install date scrawled on it, appears to be from 2005.

Radiators upstairs on the third floor (roughly 30 feet vertically from the boiler) were cold most of last winter. I ended up doing space heaters for my kids. Good times.

Anyways, you get the idea. Quite a bit of "debt" on the property I need to address. To that end, I am thinking I should abandon the current unit and replace it with something new and great. I spent a good portion of this year saving up for this, so that maybe is realistic.

That said, I do not exactly know how to buy a boiler. I do know I don't want a combi unit or whatever. After seeing a dinosaur of a system like this survive for almost 70 years, I am a believer in this technology.

I have a written estimate for a slant-fin cast iron. They sized that for 105mbh. They never really asked me about square footage, never saw the rest of the house, and never did a "heat loss" (I am learning!). I do not know how they came to 105 being appropriate.

An original estimate for this install was provided in march, and that came in at about . I just went back and asked for timing for an install, and they have now indicated that the whole thing will be . Less than 6 months has passed. Leaves me concerned about this vendor.

Anyways, I got this idea in my head that I should get a Bosch. I like Bosch tools, I am engineer, and I think they make good products. Started looking at Berderus. Wondering what people think about those. Wondering if that is considered a "great" boiler that could last 30 years. Wondering about whether I need a certified Bosch installer for some warranty stuff there.

I am really at step 1 here, so by all means, set me straight in terms of how best to think about this.

Thanks in advance. Very interesting to read this forum as a lay person.

note: property is not designated historic, just is very old.


    EBEBRATT-Ed Member Posts: 11,998
    Bosch makes good boilers but I am not in favor of them because they use aluminum heat exchangers. JMHO

    You will get various opinions here some (like me) prefer old school cast iron. Others think we are nuts and you should put in a mod con.

    There is no right or wrong answer IMHO.

    Both have advantages and disadvantages and I will leave it to others to comment on the pros and cons

    But the first step is an accurate heat loss. Your contractor should do one (most will not)

    Download the Slant Fin app and do your own.

    That's the first step
  • kamelkev
    kamelkev Member Posts: 9
    edited September 2021
    That's helpful.

    I was looking at a G234x. This appears to be cast iron, but Im guessing they have alum models outside of this.

    One of the things I noticed was how a variety of boilers actually wouldn't deliver a warranty for a multi-unit property like this. The nice thing about Bosch was that they had a carve out for a two unit building, which is what this effectively is.

    I downloaded the SlantFin app. It is ... burdensome. Do we know roughly what it would cost for a contractor to do this?
    EBEBRATT-Ed Member Posts: 11,998
    edited September 2021
    A good contractor will do a heat loss, most won't. They don't wan't to take the time fearing they won't get the job so they put little effort into it. They might have to quote 8-10 jobs to get 1. Most size off the existing boiler, the radiation load or just .............guess.

    All 3 ways are wrong for hot water

    Actually Slant Fin is a simplified heat loss. Not burdensome at all. You can count the whole house as 1 big room and don't have to calculate each room if you don't want to. The boiler size will be the same
  • Ironman
    Ironman Member Posts: 6,868
    As Ed stated, the heat loss calc is the first step and the foundation for everything.

    Bosch owns Buderus. I’m not a huge fan of the Bosch Green Star mod/con, though I’ve installed a few. 

    If you’re going with a mod/con (I would), then I’d recommend the HTP EFTU or IBC’s version of it. We put in several, including my own house, and we’re very well impressed with it.

    If you decide to go the cast iron route, then the Buderus literally makes the best. However, be advised that if you go with any cast iron atmospheric boiler the chimney will have to be relined due to the lower flue gas temperatures of a modern, more efficient boiler.

    The most important factor is the contractor that you choose; he’s 95% of the equation. Try the contractor locator above.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Jamie Hall
    Jamie Hall Member Posts: 18,935
    I'd agree with all of the above -- except that as I recall there seem to be very few if any contractors known to us in the Denver area. Not sure why.

    On the heat loss calc. I'm not sure I'd call it burdensome -- I've used it quite a number of times and never found it so -- but on the other hand it doesn't provide instant results and one does have to know how the house is constructed and so on. It's a good deal better than doing it all by hand... the trouble, of course, is that there are so many variables in construction that any rule of thumb instant answer type of thing can't possibly be right, except by accident.

    That said, however, there is no substitute for a heat loss calculation in sizing a hot water -- or for that matter forced air -- boiler or furnace. Nos shortcuts on that one, not if one wants it to provide the comfort one wants and be efficient or at least reasonably so at the same time.

    All of which thinking suggests a way for @kamelkev to approach finding a boiler -- and a contractor. Is the contractor interested in -- and willing and able (perhaps for a small fee?) -- to do the heat loss calculation, and give you the results? If so, they are probably also interested in and able to do a decent job of the install. So... then, what boiler do they like to install? And there you go...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Zman
    Zman Member Posts: 7,330
    What is the condition of the existing flue. That often tips the balance in the mod/con debate. I am guessing that your existing boiler vents through an old masonry chimney. The chimney will probably need a liner if it is to be reused.
    If you are going with an atmospheric boiler, the Buderus cast iron would be an excellent choice. If you go the Mod/Con route, it comes down to installer and local manufacture support. In Denver, Lochinvar is king.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Zman
    Zman Member Posts: 7,330
    Your original post shows pricing. site rules prohibit talking price, please edit.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Erin Holohan Haskell
  • kamelkev
    kamelkev Member Posts: 9
    Appreciate the insights.

    I have reached out asking if the contractor can help with a heat loss. I like that as a litmus test.

    The comments on the chimney are dead on. My chimney has some vertically cracked brick, which is a little weird. Only place on the house with that issue. My guess is the hot air getting vented into freezing cold brick caused it to crack along the stress lines. I am planning on a liner there.

  • kamelkev
    kamelkev Member Posts: 9
    Tried the contractor search above, but unfortunately it appears nobody within 100 miles.

    Been hard to find a good outfit to work with out here. Lot of places are only in business a couple years. The various numbers I found written on the current boiler - all those places are out of business. Too bad, as they clearly kept this thing running for quite a while.
  • Mark Eatherton used to be a frequent contributor here on HeatingHelp and the last time I spoke with him, he was working for a hydronic contractor in Denver. Give him a call 720-375-3107.
    Often wrong, never in doubt.
  • JeffM
    JeffM Member Posts: 178
    Contacting Mark is a good suggestion, I think he's still working in Denver (or was the last time I worked with him on some code development). I'm in a Denver home of the same age, though unfortunately with forced air. If that phone # doesn't get you to Mark look him up on LinkedIn and send a message. I also have an HVAC company here that I like for my mini-split system; they might do boilers, so if you still need contacts drop me a direct message and I'll give you their info. What part of Denver are you in?
  • Robert_25
    Robert_25 Member Posts: 406
    If you are not having any luck finding a contractor, I suggest contacting your local supply house for HVAC equipment. There is a good chance they can point you to a local contactor, and if you are lucky - the supply house will have a heating guy on staff just itching to size a boiler for an old house.

  • Steamhead
    Steamhead Member Posts: 15,331
    Isn't @Dave Stroman in Denver?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Zman
    Zman Member Posts: 7,330
    Four seasons heating used to post here a fair bit. I cannot remember his name.
    @SeanBeans was working for a contractor in that area.
    @delta T is somewhere in the state.
    Gregg Gibbs over at Shamrock Sales would likely give you a good referral.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • delta T
    delta T Member Posts: 870
    I am in Trinidad, which is "almost New Mexico, Colorado". I'm 3.5 hrs or so South of Denver, definitely out of my service area. Zman is dead on though, Gregg Gibbs is a great guy and would definitely be able to point you in a good direction.
  • mattmia2
    mattmia2 Member Posts: 5,521
    I would take a step further back. If the old boiler isn't leaking or otherwise damaged, I would suggest once you find someone that really knows hot water heat that you look at cleaning the boiler, fixing the zone valves, and fixing the circulator(maybe it is just being deadheaded against the malfunctioning zone valves). That could buy you quite a bit of time to save up for replacement or possibly let you do it in stages such as abate the asbestos now so there is less to do when you do have to replace the boiler. Replacing the near boiler piping with the new boiler might solve your problems or it might not, the system problems need to be addressed specifically regardless of if the boiler is replaced or not.

    The boiler controls are a little less safe that modern controls, but unless it is some ancient modulating system it is still pretty safe. Old gas valves can stick open so replacing the gas valve with a modern combination vale if it is original wouldn't be a bad idea.
  • kamelkev
    kamelkev Member Posts: 9
    Appreciate all this information, max helpful.

    Had a pleasant conversation with Mark. His company appears to be doing quite well, but they are booked out until next year for new installs.

    Email sent to Greg Gibbs. Appreciate any other specific contacts within this area who may be able to help.

    @mattmia2 there is a real chance I end up having to go down this path, but I really really don't want to throw good money after bad. We want to get all this asbestos out of the house anyway, and all the ancillary equipment on the thing is toast... seems like wholesale replacement is the "most efficient" - but if we can't get the work done in a reasonable timeline, we wouldn't necessarily have choices anyway.
  • Zman
    Zman Member Posts: 7,330
    `71 years is way above the life expectancy. You are on the right path. Just be patient and find the right contractor.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • kamelkev
    kamelkev Member Posts: 9
    Appreciate all the help everyone. I was able to connect with Greg Gibbs, and he's made a referral he believes is solid.

    Plan right now is to fix up existing system, get the chimney fixed up, and then plan for full-scale replacement in spring when we think it may be easier to schedule the abatement back to back with the install.

  • tim smith
    tim smith Member Posts: 2,460
    Question for you, do you know what your annual gas bill is? Would be helpful in vetting out choices. What kind of radiators? Fin tube or cast iron. If cast, how tall, how many sections, maybe a photo or 2 if all rads are same style. All this related to heat loss will help decide what benefits most.
  • BigRob
    BigRob Member Posts: 308
    My 2 cents from over 10 years of using mod cons in a 12 condo multi family building. We have two Lochinvar boilers. One is a coil heat exchanger floor standing Lochinvar Knight 285k for hot water and the other is a wall mount 199k fire tube Lochinvar for 10k sqft thin slab radiant floors and 4 wall radiators. Both boilers are circa 2012. I'm impressed with Lochinvar and would buy another boiler from them for sure. The only issues have been the LCD displays are messed up in small spots, which they could have avoided by turning off the display after a couple minutes. Lochinvar probably fixed this by now. The 285k has over 70k ignitions. No breakdowns. The inducer fan is still smooth running and it runs great. The 199k also has a good amount of ignitions and is setup to condense like a mofo. Lots of condensate to neutralize and you have to change the neutralization media with a mod con which is annoying. Even though I would 100% buy a Lochinvar- not sure I would get a mod con unless the fuel savings for the application is really worth it. I'm not convinced it is. The system has to be setup right AND not messed with by hacks or you lose your gains. Unless the return water temperature is pretty low you don't get that much benefit and mod cons are very complicated with custom microcontroller circuit boards that are expensive to replace. The pump relays are generally not replacable like in a taco pump controller- they are integrated on the custom circuit boards. If it fails, you have to replace an expensive board. Personally, if I was you, I would look at your potential fuel savings with a mod con and balance that with the likelihood of a complex boiler repair. Technically, you are supposed to have a mod con serviced every year. I have found this is not the case, although I may be wrong. In SF the cost of yearly service is high and not having it done over 9 years has funded a new future boiler. I did open the floor standing Knight and the coil was in good shape after 9 years in a 185F indirect water heating application. The fancy mod con controls are cool. I use an analog sensor in the hot water tank and the Lochinvars will control 0-10V ECM pumps. They have outdoor reset and a bunch of configuration options you really don't need in a residential application. The reason your old boiler lasted so long is because it's probably cast iron with relay controls, a gas valve, and an ignitor. Super easy to diagnose and fix. I've seen some cast iron heat exchanger boilers that are designed for condensing. Looked interesting, especially if the controls are simple.

    Before our indirect hot water tank we had an Ergomax reverse indirect. It sprung a leak at a union and rusted out after years of neglect (before I was around). It was scheduled for replacement as I arrived and I played with it a little. I'm a fan. You get hot water and buffering in one package. Our original heating system was well designed, but was maintained by idiots. It was a simple copper tube boiler feeding the ergomax and all the heating zones valves. One boiler circulator for the ergomax and one for the zones with a pressure bypass and thermostatic mixer. Super simple. The contractor that sold the Knights to the HOA was a real crook- added another gas line (LOL) for a second boiler and installed a primary secondary loop monstrosity that short cycled like a mofo. We had to fix a lot. Honestly, we would probably be fine with a 199k boiler for the whole building considering load diversity. Check out the Turbomax or Ergomax reverse indirects. Might be interesting for your application.
    tim smith
  • kamelkev
    kamelkev Member Posts: 9
    UPDATE: Greg Gibbs helped me out, and directed me towards a local contractor. We've since replaced the zone valves, replaced the pump (old taco was from 2005...), and fixed an issue where we had multiple purge mechanisms that appeared to be letting air into the system.

    The system is significantly quieter now. The next step is to get the chimney lined, and then in March we plan to replace the system with a Buderus. The contractor is planning to do sizing based on the heat loss calculation and soforth.

    I think my big challenge now is finding an asbestos abatement company to assist with the demo of the old system in the spring. Also, I will need to figure out some solution for four radiators with "Honeywell Unique" valves. Three of those radiators do get hot, but the knobs are seized. The last one is ice cold, we think it's stuck closed. I will probably post in a different thread with pictures for that particular issue.

    @tim smith I purchased this property early in the year, and don't have a full year's worth of billing. That said, I can estimate...

    For reference, March was $350 dollars. That's not even our coldest month...

    My educated guess is something around 1500-1600, just the boiler.

    @BigRob I'll check out the models you mention in your post. Appreciate the context there.
  • mattmia2
    mattmia2 Member Posts: 5,521
    You might be able to rebuild the unique valves. There is a danfoss valve with a lance that can feed the radiator through a single tapping, might take some creative fittings to fit it in.
  • tim smith
    tim smith Member Posts: 2,460
    I totally agree with @BigRob, Lochinvars have mostly been bullet proof for us. Installed the very 1st production WHN firetube boiler in the USA. Few igniters, one failed heat x, no blowers, burners, main boards. Out of over a 100 +. Commercial up to 60 unit bldgs & single family. Really been a solid performer. Some of the early FTXL firetube, ie larger btu units, had some doa leakers. They took good care of us on those and other than than, solid. My .02 worth.