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Lochinvar Knight boiler problems

crickacricka Posts: 19Member
Last fall, we converted our heating system from an ancient steam heating system to a hot water system (gas heat). Our house is from 1923, about 4700SF, stone masonry construction, 25 radiators (2-pipe) converted. After much looking into gas boilers, we decided to go with a Lochinvar Knight mod-con boiler, the KBN400. The installer was someone recommended by Lochinvar, so presumably they are trained in these boilers and know what they are doing. So we thought we were finally going to be rid of our worries and problems with heat in the winter. True, the heat we have is more comfortable, and the cost is about 75% of what the old system cost (more than we had expected from the new system, but still much better than what we were previously paying). On the other hand, the system is barely over one year old, and we are having problem after problem with it.

First, no heat b/c of an "ignition lockout". This happens on a Saturday evening, of course. Technician comes on Sunday, replaces the ignition cable and ignitor. All fine and good.

A week later, Sunday morning, same problem: no heat, same message on the boiler. Technician comes out same day, but unfortunately, it's a bad main board this time; the installer has none in stock; the local supply house has none either, so we have to wait until Tuesday afternoon to get a delivery from the company in Tennessee. This of course happens on the coldest weekend of this winter, and we are without heat or hot water for 3 days - no fun!

Board replaced on Tuesday, then 4 days later, on Saturday, we are again without heat. This time it's a blocked drain. Condensate trap and switch cleaned, and all is fine for now (barely one week later). Thank goodness we don't live in a really cold climate (Philadelphia), and that it has been a really mild winter.

What's next? Given that a weekend is coming up, we almost expect a problem again. We are now very concerned about this system, and worry that we can't go out of town for even a few days in the winter because the system might fail again! And we dread a cold winter. This is not what we expected with a new boiler.

What we would like to know is: Should we just expect this sort of breakdown? Did we get a lemon of a boiler? Is the Knight boiler prone to such problems more generally? Could there have been a problem with the installation?

I would also like to warn other potential buyers that it may not be a good idea to get an indirect hot water system to run off the boiler: if the boiler stops working, you will not have any hot water either!
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Comments

  • Larry (from OSHA)Larry (from OSHA) Posts: 664Member ✭✭
    edited February 2012
    please send pictures

    Hello cricka,



    Really need to see several photos of your system.  How it is piped up and the more photos you can post, the better.  Even though you have a pretty good size home with perhaps marginal insulation, the KBN400 seems a bit large for your home.  If it is very oversized, this can lead to not getting the savings that you were expecting.  Post some pictures of the venting as well.  It sounds like some of your issues may be installation related.



    I have a Knight KBN80 that has warmed our house since 2007 quite flawlessly.  Our place is about 3000 sq. ft. and fairly well insulated for your comparison.



    People here can help you if you give more info.



    Larry
    · ·
  • cricka2cricka2 Posts: 3Member
    photos of our setup, KBN400

    Larry,

    I hope these photos help. My husband had thought we were getting too large a furnace, but the installers said not to worry. As far as we know, they did NOT do a heat loss calculation. Any advice you can provide will be most appreciated.



    (I could not log on to my account with my known password, so I set up a second account, and therefore needed a different nickname.)
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  • cricka2cricka2 Posts: 3Member
    second attempt at photos

    Larry,

    Sorry, my first set of attachments got removed when I had to change my nickname
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  • cricka2cricka2 Posts: 3Member
    photos

    The first 6 photos should be rotated 90 degrees clockwise. The final 3 are OK as is.
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  • IronmanIronman Posts: 2,192Member ✭✭✭
    Knight Boiler

    Let me first set your mind at ease concerning the Knight boiler. It is an excellent product and is probably the best controlled mod/con around. Board failures due happen and every manufacturer experiences them. That failure may have been caused by a voltage spike. The distributor should have had that part on his shelf; maybe he ran out, but doubt it. Lochinvar immediately shipped one the next day. You can't ask for any better than that from the factory.



    The blocked drain is a maintenance issue and all mod/cons produce the same amount of condensate under the same circumstances. No fault of the boiler there.



    Regarding the installation:



    Your contractor did the install in a workman like manner and for that he is to be commended.



    However, there are some issues that I see just from the info and photos provided:



    1. I believe that the boiler is grossly over-sized for your home. It is a 400k btu boiler; your house is 4700 sq. ft. That comes to 85 btus per sq. ft. Even an old home that is leaky and poorly insulated in the Philly area should not require more than 45 btus per sq. ft. - and that's when it's 0* outside. If insulation has been added and windows upgraded, you're probably in the 32 - 35 btus per sq. ft. range.



    Did your contract do a heat loss calculation to size the boiler? Ask him for it and post it if he did, please.



    2. Converting a steam system to hot water is usually not a good idea. There is a thread on the "Main Wall" of this site right now that discusses this. Here's a link:



    http://www.heatinghelp.com/forum-thread/140627/Two-pipe-steam-system-converted-to-water-with-condensing-gas-boiler



    3. It appears that at least one zone of your system is over-pumped. The large pump that is farthest away from the boiler in your pics is a Grundfos "VersaFlo". It comes in four sizes and the smallest would be way over-sized on almost any residential application. We would have to know the particulars of the piping and the load for that zone to confirm this, but 40 years experience tells me it's probably not right. Over-pumping, like boiler over-sizing, is not a good thing.



    4. I cannot see an expansion tank in any of your photos. There may be one, but I don't see it. The old steam system would not have had one; therefore, your installer would have had to install one. It's a crucial component. It should have been connected to the bottom of the SpiroVent. That's the large brass canister near the big pump.



    5. You have a low water cut off installed on your system; that's a good thing. It's installed too low in the piping; that's not good. It's the small black box down on the supply line beside the boiler with cable coming from it to the boiler. It should be placed as high above the boiler as reasonably possible.



    Some more questions:



    1. Did your contractor setup the boiler with digital instruments and do a combustion analysis? If so, ask him for the printout. If not, ask him why. It's required.



    2. The boiler is vented into the wall into what appears to be an old chimney. Is the chimney being used as a chase or is the boiler actually venting into it? Can you take some pics of where the vent terminates?



    3. What modifications did your installer make to the piping to convert the system to hot water?



    A word of caution.



    Most, probably all installers won't appreciate their work being questioned or critiqued. Be gracious and not accusing when you speak with him. As I stated, he sold you a good product and did good workmanship on the installation. Try and work together to get any issues resolved. If he has questions about what's been pointed out, send him here. This is "Heating Help" and that's the goal: to help.
    Bob Boan







    You can choose to do what you want, but you cannot choose the consequences.
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  • crickacricka Posts: 19Member
    More info about our boiler

    Ironman,

    Thanks for the info. I had done a fair amount of reading about modcons, and it seemed that the Knight boiler had a lot of positive reviews - that's part of the reason I am upset with our problems. Also, 3 weekends in a row of having no heat or hot water is upsetting. I'm glad to hear that the product is still highly regarded, and that we just ran into some flukes all at about the same time.



    In response to your points:

    1. I'm almost certain no heat loss calculation was done, but will check with our contractor. I had thought that it was oversized (it replaced a 500K BTU steam boiler of 80% efficiency at best i.e., when new); however, the contractor said it was the right size. Doubly annoyed now, because we couldn't get the sizeable PA state rebate for this boiler - it's commercial-sized, not residential, so no rebate.



    2. I had read the arguments pro and con converting before we went ahead with this. Yes, each and every one of our radiators had to be converted (it was a good two-pipe system), and in fact the contractor thought the rads had originally been meant to for hot water. We have had no problem with leakage, and are pleased with the type of heat generated. Our previous steam heat was not very comfortable - hot (extremely) rads only when heat was being called for; when air temp got up to the set temp, rads would get stone cold, with no heat radiation from them, so even though air temp said it was, say, 69F, it would seem cold. We lived with this system for 15 years, and I had had enough. At one point, we found a older steam contractor with loads of experience who almost got the system to work well (i.e., heat in the rads a good bit of the time), but the year after we found him, he retired, and we could never again find somebody who seemed to know how to make it work well. I guess steam heating systems are disappearing, so fewer contractors who really know them well.



    3. Thanks for letting us know about the pump - it's pretty noisy and we hear even on the 3rd floor! When we complained to the contractor about the noise, he had no solution (it seems now that the solution may have been to put in a smaller pump).



    4. We do have an expansion tank - it's in back of the boiler. I can upload a photo of that if that if it helps. I will also go check how it's conected.



    5. I will ask my contractor why the low water cutoff is where it is.



    6. I don't know whether a combustion analysis was done  - again, will need to ask.



    7. The venting is through the chimney - vent terminates at the top of the chimney. On a 3 story house, that's pretty high up, and I don't think I can easily take a pic that will show anything.



    Thanks for the heads up about dealing with our contractor. I of course know this in theory, but it never hurts to be reminded that good contractors take pride in their work and therefore don't like to be criticized –:)
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  • crickacricka Posts: 19Member
    oversized?

    Ironman and Larry:

    Both of you mentioned oversizing of the boiler (and the pump) as a possible problem. Besides the fact that we aren't getting as good fuel savings as we could with a properly sized system, what other problems could be casued by oversizing?



    Ironman:

    The main pump we have on the system is a Grundfos model C, PC 1014, P-N96402730.

    The low water cutoff is above the top of the boiler, but could easily have been installed 2.5' higher.

    The expansion tank is not connected to the Spirovent, but to a line that drains the boiler and that has a pressure and temp gauge on it.

    Aa far as condensate drainage - it appears the contractor probably didn't clean out the drain during the first anniversary inspection of the system. When the drain blockage occurred, they found a 1/2" ball of mesh, probably PPC glue from when the system was assembled.

    The main changes in piping on converting from steam to HW: the 3-4" steam supply pipes were replaced with 2" lines for water; for each radiator, the steam trap was removed and a vent was added at the supply side, top of radiator.
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  • alotlikeearlalotlikeearl Posts: 67Member
    ?

    Where is the expansion tank?  I don't see one in any of the pictures.
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  • IronmanIronman Posts: 2,192Member ✭✭✭
    Over-sizing

    An over-sized boiler will short cycle which will reduce the efficiency and life of the boiler or its parts.



    The simplest solution, other than replacing it, is to install a properly sized buffer tank that will cause the boiler to have a ten minute minimum run time.



    Pump over-sizing will cause a number of issues: high water velocity, noise, pipe erosion, reduced radiator performance, higher electric consumption, etc.



    I cannot tell you for certain if the circulator (proper term) in question is correctly sized. In order to do that I would need to know the gpm required for the loop based on the calculated load, the pipe size and length, the type and number of emitters on the loop and anything else that might add resistance to flow (head) in the loop.



    The number that you supplied is not the model number of the circulator. It should start with "UP", followed by some numbers. Like "UP43-70" or "UP43-110", etc.



    If you can give that and the pipe size and its total length (supply and return) and number of emitters (radiators, etc.), I can give a ballpark on the sizing. But as you can see, this is why a load calc. is necessary; it's the starting point for sizing everything: boiler, piping, pumps, emitters, etc.
    Bob Boan







    You can choose to do what you want, but you cannot choose the consequences.
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  • IronmanIronman Posts: 2,192Member ✭✭✭
    One More Thing...

    I noticed that the air intake pipe is only 2". It should be 4". The boiler comes with an adapter to increase it to 4" at the boiler. Your installer may have done this inside the chase , but it should have been done as soon as the pipe exits the boiler. A 4" pipe carries about eight times that of a 2"



    The burner might be lacking sufficient air for proper combustion. That's why a combustion analysis should have been done.
    Bob Boan







    You can choose to do what you want, but you cannot choose the consequences.
    · ·
  • ZmanZman Posts: 2,264Member ✭✭✭
    A couple of thoughts

    Bob, as usual has this problem accurately evaluated.

    It appears as though the service tech may be attempting to troubleshoot by just replacing all the parts. Has he been working with Lochinvar to determine the problem?

    I think that is is very likely the problem is being caused by something like,poor combustion,2" intake, overpumping, oversized boiler. and the tech is convinced the controls are at fault.

    How long does a typical boiler cycle last?

    Does this model have a combustion test port?

    Is there a hole drilled for one?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
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  • SlimpickinsSlimpickins Posts: 308Member
    edited February 2012
    test port

    To do a combustion analyst you remove the flue temperature sensor and use that port. As far as the boiler being over sized you can live with it by doing some creative parameter adjusting and/or using a buffer tank. Can't comment on over pumping, like Ironman said, need some addition info to determine. Where your primary loops closely placed tees connect to the secondary loop, I'd like to see a longer run on the secondary before the elbow. Iron is correct on the intake air being undersized, needs to be 4 inch like the exhaust. Also the gas should be piped 1" to the boiler, the 3/4 CSST flex can't carry the needed BTU's. Also the make up water should be tied in with a tee at the plug where the air remover is with the expansion tank on another tee at that point.  If its any consolation, I've seen worse
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  • RobGRobG Posts: 1,546Member ✭✭✭
    Knight 400

    All of this has been stated before however these are critical issues.

    1. The gas piping IS undersized. 5 foot of CSST (The yellow flex connector) will only provide 344,000 BTU's. Your boiler is rated at 399,000 BTU's.

    2.The air intake pipe MUST be 4 inches, the same size as the exhaust. An adaptor was supplied with the boiler. Even if the installer up-sized the piping in the chimney it is still incorrect as the adaptor must be installed at the boiler so it may be inspected annually. (please post a picture of the termination on the roof as this will tell us allot).

    3. Once items one and two are corrected, a digital combustion analyses MUST be performed to set the boiler up correctly. You should be provided with a printout of the combustion analysis. (once that is done please post the results here so we may verify the numbers)

    Good luck, Rob
    · ·
  • crickacricka Posts: 19Member
    some more info about our system

    I have attached 4 photos of the expansion tank showing piping for it.



    The pump we have is a Grundfos UPS 32-160F.



    As far as the piping: all the piping except for the risers to individual radiators is new copper. The main distribution loop is 133' of 2.25" pipe; the zonal distribution is 151' of 1.25"; runs off the main circulation to individual rads are 21' of 1.25" and 310' of 7/8". For the old galvanized risers, we have 178' of 1" and 203' of 3/4" pipe.



    We have a variety of radiator sizes; following is a list providing: height of radiator, OD in (OD out was always 3/4" except for the one fin radiator we have), # tubes/section,  total # of sections (# radiators):

    1'11" H ––  1" OD in ––  3 tubes/sec  ––  68 sections (2 radiators)

    1'11"    ––   1"     ––        4      ––                5 (1)

    1'11"   ––    1"     ––        5      ––              25 (2)

    1'8"    ––     1"    ––        3       ––            143 (7)

    1'8"    ––     1"    ––        4       ––              17 (1)

    1'8"    ––    3/4"  ––        4       ––              33 (4)

    1'8"    ––     1"    ––        5       ––              30 (2)

    1'8"    ––    3/4"  ––        5       ––                4 (1)

    1'8"    ––     1"    ––        6       ––              10 (1)

    1'6"    ––     1"    ––        7       ––                9 (1)

    2'5"    ––     1"    ––        5       ––              10 (1)

    2'5"    ––     1"    ––        6       ––              10 (1)

    and 1 fin radiator: 13.75" x 28.25" x 3"



    We have no idea how to calculate volume of water held in each type of radiator; is there some place we could find this info?



    We also have a question about the pump for the main circulation: when should it shut off - when the boiler quits heating water; or should it continue to run for some considerable time after that? It seems to me that last heating season, the pump ran only when heat was being called for, but this season, it seems to run for much of the time (and our electric bill is correspondingly much higher).



    Any help you can provide us will be much appreciated.
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  • crickacricka Posts: 19Member
    photos of the expansion tank

    Sorry, the photos didn't go through a few minutes ago. Here they are.
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  • crickacricka Posts: 19Member
    2 more photos of expansion tank

    The remaining expansion tank photos.
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  • crickacricka Posts: 19Member
    More problems

    We have had additional problems with our KBN400 heating system: 3 times since the last problems we had, system stops working, the info screen on the boiler says "output temp diff". Fortunately, we can hit the reset button and the system starts up again, but I think this should not be happening. We feel like we can't leave the house even for a weekend trip away without worrying that there will be no heat and no hot water! Anybody know what could be causing this problem?
    · ·
  • crickacricka Posts: 19Member
    More info about our system

    Ironman,

    I have attached 4 photos of the expansion tank showing piping for it.







    The pump we have is a Grundfos UPS 32-160F.







    As far as the piping: all the piping except for the risers to individual

    radiators is new copper. The main distribution loop is 133' of 2.25"

    pipe; the zonal distribution is 151' of 1.25"; runs off the main

    circulation to individual rads are 21' of 1.25" and 310' of 7/8". For

    the old galvanized risers, we have 178' of 1" and 203' of 3/4" pipe.







    We have a variety of radiator sizes; following is a list providing:

    height of radiator, OD in (OD out was always 3/4" except for the one fin

    radiator we have), # tubes/section,  total # of sections (# radiators):



    1'11" H ––  1" OD in ––  3 tubes/sec  ––  68 sections (2 radiators)



    1'11"    ––   1"     ––        4      ––                5 (1)



    1'11"   ––    1"     ––        5      ––              25 (2)



    1'8"    ––     1"    ––        3       ––            143 (7)



    1'8"    ––     1"    ––        4       ––              17 (1)



    1'8"    ––    3/4"  ––        4       ––              33 (4)



    1'8"    ––     1"    ––        5       ––              30 (2)



    1'8"    ––    3/4"  ––        5       ––                4 (1)



    1'8"    ––     1"    ––        6       ––              10 (1)



    1'6"    ––     1"    ––        7       ––                9 (1)



    2'5"    ––     1"    ––        5       ––              10 (1)



    2'5"    ––     1"    ––        6       ––              10 (1)



    and 1 fin radiator: 13.75" x 28.25" x 3"







    We have no idea how to calculate volume of water held in each type of radiator; is there some place we could find this info?







    We also have a question about the pump for the main circulation: when

    should it shut off - when the boiler quits heating water; or should it

    continue to run for some considerable time after that? It seems to me

    that last heating season, the pump ran only when heat was being called

    for, but this season, it seems to run for much of the time (and our

    electric bill is correspondingly much higher).







    Any help you can provide us will be much appreciated.
    · ·
  • IronmanIronman Posts: 2,192Member ✭✭✭
    Service manual

    Cricka,



    Look at page 42 of the service manual. I'm not sure what it means by "excessive temp differential 'between the two sensors'. " Not sure which "two sensors" they mean as there is also a fault code for "Delta T High" on page 44 which would refer to the difference between the supply and return sensors. Maybe a call to Lochinvar tech support should be made for clarity.



    Nevertheless, the sensors should be tested for the proper resistance/temp as per the chart.



    Dan has an EDR (radiator sizing) table under one the resource links above that you can determine the square footage of your rads from. Multiply the sq. ft. x 150 to get the btu output.
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    Bob Boan







    You can choose to do what you want, but you cannot choose the consequences.
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  • crickacricka Posts: 19Member
    Where to find EDR ratings

    Ironman,

    I have looked through resources and done a search, but the only thing I can find that provides EDR ratings for cast iron radiators is a book by Dan Holohan that I would have to buy. Is there any online source that would have this info? Perhaps I just don't know where to look.



    Thanks so much for the Lochinvar Knight manual. I may yet get to know more than I want to about these boilers and this system.
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  • crickacricka Posts: 19Member
    Found it!

    A bit more search of the web, and I found a table with SF for different radiator sizes.
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  • IronmanIronman Posts: 2,192Member ✭✭✭
    edited March 2012
    How about this

    We don't need the water volume of the rads, but the heat output.
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    Bob Boan







    You can choose to do what you want, but you cannot choose the consequences.
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  • RobGRobG Posts: 1,546Member ✭✭✭
    Air intake pipe size, Gas Suply, Combustion Analysis

    Cricka, until the three items above are addressed, you will never be able to asses the other issues at hand. If your air intake pipe is 2" instead of 4" all the way up that chimney, your boiler is starving for air and will never work properly (that is why pictures of the termination at the top of the chimney are requested). Your gas supply appears to be undersized. A combustion analysis is required to ensure the boiler is firing correctly. These are just for starters, but they must be corrected before it's possible to look further. (who knows, it may just solve your problems altogether)

    Rob  
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  • gennadygennady Posts: 524Member ✭✭
    "output temp diff"

    if water flow is not sufficient, at minimum load water is overheated and temperature difference on inlet and outlet of the boiler increase to much and too fast. boiler control protects heat exchanger and locks out. expansion tank and boiler feed line connected in wrong locations. boiler is over sized at least 3 times. and person installing it has little knowledge in those systems. Find a good contractor in your are to clear this mess. it is not a matter of problem within installation, this is a problem with whole installation.
    Gennady Tsakh



    Absolute Mechanical Co. Inc.

    www.AbsoluteMechanicalCoInc.com
    · ·
  • gennadygennady Posts: 524Member ✭✭
    edited March 2012
    .

    .
    Gennady Tsakh



    Absolute Mechanical Co. Inc.

    www.AbsoluteMechanicalCoInc.com
    · ·
  • crickacricka Posts: 19Member
    Additional info

    Ironman, RobG, and Gennady -

    Thank you for all your help. It sounds like we got ourselves a bit of a nightmare. We looked back at the contract that we had signed, and it had specified a KBN210, not a 400! We have no idea why a 400K BTU was put in - it was not discussed, or OK'd with us, it just was what they installed and presented as a done deal. So we are going to try to go back to the company and get them to put in what the contract stated - apparently the foreman who did the installation is no longer with the company.



    We did an EDR estimate of our radiators - 830.7 SF, plus the one fin radiator (no idea how to estimate that); multiplying by 150, we come up with 124,600 BTU - so as Gennady says, we have a boiler that is 3x what we need.

    Rob - we are trying to get pics of the top of our chimney, and will post if we get them. If we get a smaller boiler installed, do we still need to go with a 4" air intake?



    So if we get the company to out in what they should have in the first place, should we go with the 210 that's in th contract, or should we try to get an even smaller boiler? Seems like we need to get the boiler fed line and the expansion tank connected differently at that time - is that a major hassle. What other changes need to be made at the same time? What size circulator do we need to run the system?
    · ·
  • gennadygennady Posts: 524Member ✭✭
    edited March 2012
    circulator

    you have to confirm to pump away principle, ( see book of same name by dan hologan), and if circulator is picked on 20F temperature differential, then divide BTU by 10000, will give you gpm of the pump, if 40F temperature differential picked ( this is strongly recommended for condensing boilers), then you need divide btu of circuit served by 20000, and pressure drop is length of loop, ( including baseboard) and then have 6 feet of water column pressure drop per each 100' . this is not exact , but will get you there. otherwise you have to do hydrolic calculations. or just get grundfos alpha and set it for autoadapt

    Regarding sizing, you have to go with heat loss calculations, not EDR, do not forget to factor in infiltrations as well. You don't know who sized your radiators. ( might be the father of the fellow who over sized you boiler)
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    Gennady Tsakh



    Absolute Mechanical Co. Inc.

    www.AbsoluteMechanicalCoInc.com
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  • crickacricka Posts: 19Member
    radiator sizing

    Gennady,

    We sized all of our radiators ourselves, just a few days ago. I don't think the contractor who installed did any sizing. Another company who bid on this job had sized the radiators, but we don't have those measurements. The latter company would, I'm sure, have done a superb job, but they were 2.5X more than the ones who did the work, and we couldn't afford them.
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  • IronmanIronman Posts: 2,192Member ✭✭✭
    Well...

    Let me ask a couple of more questions:



    Is that all the radiators in the house or just what's on the large loop? Can you separate the EDR for each loop so we can size each circ accordingly?



    Heat Loss, heat loss, heat loss. Someone must do an accurate heat loss calc. to size the boiler, circs, piping, etc. The contractor should have done this before a boiler size was selected. SlantFin has a simple heat loss program that you can download and do you own. Most jurisdictions require a heat loss to be done when a boiler is replaced. All should require it.



    The sizing of the vent piping will depend upon the size of the boiler selected. Again, that's gonna require a heat loss. I know that I sound like a broken record, but that's the starting place and you wouldn't be in the situation that you are in if your contractor had done one in the first place. You've gotta start at home plate, not second or third base.



    If the number that you've given (830 sq. ft.) is the total EDR which = 125k btu's, then you shouldn't install a boiler that has any higher output than that. This assumes that the heat loss confirms that is sufficient to heat your house. If not, more radiation should be added. Remember, the rads had a much higher output when they were on steam. They may not be sufficient now.



    Make your contractor do the heat loss and calculate your EDR. Don't give him the numbers you came up with. Make him do it on his own and see how close he comes to yours.



    Again, I would suggest that you do your own heat loss and then see how close the contractor comes to your numbers. That way you'll know if he's being straight with you or not.



    Also, make him put in writing that he will size and install the new boiler according to Lochinvar's spec's and instructions and do a digital combustion analysis and give you the analysis printout.



    Please keep us informed of how things go.
    Bob Boan







    You can choose to do what you want, but you cannot choose the consequences.
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  • crickacricka Posts: 19Member
    Boiler sizing

    Gennady,

    How did you come up with the figure that our boiler is oversized a factor of 3?
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  • gennadygennady Posts: 524Member ✭✭
    edited March 2012
    boiler sizing

    I do heat loss on each job i do a few different ways, one using HVAC-calc software , another with fuel bills and heating degree day methods, and i developed a feeling of right and wrong. i never go by the feelings, but it helps. i have yet to see private house needed 400MBH boiler. I consistently scare customers with my sizing, putting in contracts paragraphs, saying that i will replace boiler to bigger one at my own expense, because i was proposing boilers much smaller than my competitors, and yet when in the past we had 6F days in NY i did not get any call with complaints. So, i would say even 125k boiler will be probably over-sized too, but you can live with that. Also get rid of zoning as well. it is messing up condensing and modulation on your boiler.I know, there few contractors agree with me, but this is how i do things.
    Gennady Tsakh



    Absolute Mechanical Co. Inc.

    www.AbsoluteMechanicalCoInc.com
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  • gennadygennady Posts: 524Member ✭✭
    radiator sizing

    This is what i mean. you calculated installed EDR, but how do you know this EDR is confirming to house heat losses? But in this case bigger is better. More radiation for condensing boiler is a very good thing. it allows to lower water temperature and make boiler condense more.
    Gennady Tsakh



    Absolute Mechanical Co. Inc.

    www.AbsoluteMechanicalCoInc.com
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  • crickacricka Posts: 19Member
    air intake termination

    Here is a photo of the chimney - the chimney width is about 6', so my very rough estimates from the photo suggest that the air intake is 4" at the top. No idea where or why it gets downsized.

    As far as a heat loss calculation, I can't use the slantfin program because we have a Mac (I know, I know I could get a program to run pc programs on the Mac, but it's a hassle, and mostly I don't need to). Anybody have a link to a good heat loss calculator program for a Mac?
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  • crickacricka Posts: 19Member
    Chimney

    Here's the photo of the chimney top.
    JPG
    JPG
    Top _of_chimney.JPG
    0B
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  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    2" pipes Vs, 4" pipes:

    Last I knew, it takes 4-2" pipes to equal a 4" pipe.

    Sounds like the bpoler has COPD, Chronic Obstructive Pulmonary Disorder.
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  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    Chimney Vent:

    That looks like a 3" exhaust pipe going through that roof flange. It isn't a concentric vent so where is the 2" intake going? I'd like to see how they got that exhaust into that flue in the chimney and got it all connected.

    Do they make a 4" concentric for this? The outside (intake) would need to be 5" or 6" Poly or PVC.

    I'll have to look at the photos again to see the exhaust
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  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    edited March 2012
    Is the near boiler piping correct?

    I just realized that I was looking at a photo of someone else's. But the same points as below apply.

    The connection of the closely spaced tees are awfully far apart.  It is supposed to be (as I understand it) is supposed to be 4 to 6 pipe diameters apart. That is 1" copper on the primary. That's a 3: to 5" nipple between the two tees. It's Center to Center. Not the length of a nipple. That spacing looks like 8".  And is the circulator pumping away or pumping THROUGH the boiler. If the primary loop closely spaced tees aren't correct, you may not get enough cooling return water through the boiler.



    I just looked at this installation.

    In the photo showing the boiler piping with the Low Loss Header and piping, is that how Lochinvar shows the piping? I've never installed a Lochinvar. But all the Mod Cons I have seen and installed have the primary pump, pumping INTO the boiler off the Low Loss Header and all the system circulators piped through the Low Loss Header and pumping away. Why are there two circulators on the boiler side of the LLH? and one on the system side of the LLH? Only the Boiler Pump is supposed to pump through the boiler side of the LLH. That's why it is there.

    Only an idiot doesn't understand how LLH'ers work. If you don't, you have no business installing these boilers. The installer probably drank too much of the "pumping away" Cool Aid and is "pumping away" from the boiler instead of the way the boiler manufacturers (like Veissmann) are telling you to pump THROUGH the boiler. So that the circulator overcomes the Pressure/resistance by PUSHING through it rather than Sucking or Pulling it. I can't tell how those two pumps are orientated, but I can see a circulation through the LLH and by-passing the boiler with a high flow. Hence, the overtemp fault in the boiler.

    JMO.

    OBTW, your description of how the system was piped and converted sounds and by the descriptions, is a horror show. The person/installer must have lost their shirt on the install because if the other contractor was 2.5 times the cost of the winning price, and he knew what he was doing, someone lost a lot.

    Its hard when you know what you are doing, to compete against those that don't. The loosing price was probably the correct price, and you got a mess on your hands. The only way I get work is to fix them. Not pleasant to tell someone what a mess they have on their hand.   
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  • crickacricka Posts: 19Member
    Stretched

    Icesailor,



    Are you saying that what's at the top of our chimney is an exhaust but NOT an air intake? In that case, I have no idea where the intake is.



    You're right that we probably would have been better off with the higher priced project; however, it was a matter of $38000 compared to $96000, and we just couldn't afford the latter. Even $38000 was a stretch. It's not always true that cheaper is less well done. We also had estimates as low as $24000 - but it seemed pretty clear to us that those guys wouldn't be able to do the job.



    At any rate, the question now is what to do to fix the problem. First thing we will ask for is to get the size boiler that was specified in the signed contract - even if not correct, it will be much closer to correct. But now from all the comments I have gotten, it seems there are a lot of other problems, and I'm not sure I can sort them all out. What is absolutely critical for the contractor to fix/change in order to have a well working system? Some of the things that were mentioned are: smaller main circulator; connecting the expansion tank to the Spirovent (?); increased size of air intake pipe; having a combustion analysis done; increase gas piping to 1". Anything else?
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  • gennadygennady Posts: 524Member ✭✭
    project cost

    Are you saying, you paid $38,000 for this mess?
    Gennady Tsakh



    Absolute Mechanical Co. Inc.

    www.AbsoluteMechanicalCoInc.com
    · ·
  • crickacricka Posts: 19Member
    YUP

    Sure did! You'd think or that money I would get a better deal out of it - at least we thought so - that's a hell of a lot of $$ to put out there for all the troubles we're having.
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