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  1. #14
    Join Date
    Jan 2002
    Posts
    1,196
    I've see 4 Munchies tied together, cascading controls, etc. My fear is that if this guys load is really over 200K, and only one zone calls, there is not enough turn down ratio on the bigger single Munch or Ultra.

    Hey, who knows which way to go until we know what load we are talking here. If he wants a 120 storage tank, he will need 240K to make that baby recover decently, along w/ the big piping, etc.

    I liken multiple boilers to putting on heavier clothing as the weather gets colder. Modulation sure helps, but has limits...

  2. #15
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,796
    I know what you mean.
    He said his bath tub holds 120 gals, I don't think he meant he wants a 120 gal indirect.

    I'm not well versed on the munchin.

    An Ultra can mod down to 20%.
    A 230 would give him a min input firing rate of 46,000.
    And 230,000 max input gives ample ability to recover an 80 gal indirect.

    But he needs a load calc done to know what he really needs for his house..

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  3. #16
    Join Date
    Jan 2002
    Posts
    1,196
    I know, I goofed on the gallonage-my wife was rushing me out the door, and the kids were screaming..

    80 gallon tank along with a mixing valve would be near impossible to run out of HW. Ought to have at least 180K net to supply it.

    As more facts come in about the posters house, it's looking like the load may indeed be lower than the present boilers capacity. I'm going to revise my opinion

  4. #17
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,517
    first i stand corrected tow 120,000btu is what i meant sorry.a load calulation should be done since we are guessing about sizeof system. going with what we know he has 240 now and dont remenber the square ft so lets just 3500 for the hell of it. is it to big or small woh realy knows mow we add and boiler mate or any other brand 80 to 120 gal depending on # of baths and showers he has mow we have with out any books in front of me lets say we need 100 to 150,000 btus for the amout of gallons per hour he needs and pipe sizes from 1in the 2in for circulation. so with all this in mind. lets say you need 200,ooo btu for the house since the odds on all zones calling at once are slim cut the down on the water heater btu to 50,000 we are at 250,000 btu. now this is off the top of my head and no real facts in front of or charts to go by. just talk and not edged in stone by a long shot ok. i deal with wielmclain so this what i am going to use for now. i need a total of 250,000 btu on a real cold day and water heater usage take but only 100 to 150 on a hot day for hot water only. since most boliers or biger than what is realy needed take two 125 boliers with a twinnig kit to cycle each as needed to main tain temp so not to have to use btus that are not needed. this is only an opinioun and to me makes sense for certain houses is this house one of themwho knows. get a load calulation and a good contractor and let him tell you the best way to go because we are all just guessing and dont know.

  5. #18
    Join Date
    Feb 2004
    Posts
    22

    additional circulation

    Thanks for all the help. One small thing that i'm not getting at all. WHen you say i sould have the indirect tank on it's own circulator, does that mean that it needs a complutely separate circulation pump? I think that is what is being said. So i'm assuming i need a separate pump as well as the priority zone part which will shut down the other house zones. If anyone can clear this up for me i'll be very greatful. I plan on calling around again tomorrow in order to find a loasd calc person.

    Thanks again.

  6. #19
    Join Date
    Jul 2001
    Location
    Delaware
    Posts
    1,232

    Re: additional circulation

    Originally posted by jmoar5
    Thanks for all the help. One small thing that i'm not getting at all. WHen you say i sould have the indirect tank on it's own circulator, does that mean that it needs a complutely separate circulation pump? I think that is what is being said. So i'm assuming i need a separate pump as well as the priority zone part which will shut down the other house zones. If anyone can clear this up for me i'll be very greatful. I plan on calling around again tomorrow in order to find a loasd calc person.

    Thanks again.
    Yes, the indirect tank needs to be on a zone by itself with it's own circulator. Do not use zone valves for an indirect due to the flow restriction they create.

    At the top of this page there is a bullseye. Click on it & for about $50 you can download & run your own heat loss calculation. You even get tech support.

    [Edited by GradyWhite244 on 03-13-2005 at 10:01 PM]
    Work is for people who don't know how to fish.

  7. #20
    Join Date
    Feb 2005
    Location
    MA
    Posts
    150
    The HVAC-Calc software is great, and Slant-Fin has a free load calc. CD, too. You can do your own calcs and compare to your contractor - chances are you do not need as much boiler as you have now.

    Condensing boilers are great, but your location and application may require higher temps (if you have cast iron radiators, for instance), so then you go with a good, standard boiler with outside air reset and piping or low-limit to prevent condensing problems. Find the best installer you can and you should get a system that you are happy with. Continue to post questions here or heatinghelp's "The Wall" and you will get all the information you need to make an educated decision.

  8. #21
    Join Date
    Feb 2004
    Posts
    22

    check valve on indirect tank?

    I was just told by a local contractor that i need a check valve installed on an indirect tank with it's own circulation pump. Is that correct? wouldn't the pump not being turned on be enough? I have another meeting this afternoon in an hour so any quick advice would really be appreciated!

    Just let me know how this thing is best installed. Please be a bit specific so i can understand!

    Thanks

  9. #22
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,796

    Re: check valve on indirect tank?

    Originally posted by jmoar5
    I was just told by a local contractor that i need a check valve installed on an indirect tank with it's own circulation pump. Is that correct? wouldn't the pump not being turned on be enough? I have another meeting this afternoon in an hour so any quick advice would really be appreciated!

    Just let me know how this thing is best installed. Please be a bit specific so i can understand!

    Thanks

    He means a flo check. A check valve won't work, because it does a different job.
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  10. #23
    Join Date
    Feb 2003
    Posts
    1,996
    A seperate flow check or one integrated into the circ is highly recommended. After the indirect has reached temp and the boiler shuts off and starts to cool down, the hot water in the indirect will try to migrate back to the colder boiler and the colder boiler water will try to move into the indirect. First Law of thermodynamics: everything wants to go to equilibrium.

  11. #24
    Join Date
    Dec 2004
    Location
    Grand Rapids, MI
    Posts
    625
    Check HeatingHelp.com, they have a find a Pro section, could not hurt to get a second bid.

  12. #25
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,517
    sounds like you dont trust this contractor very much or he is not explaining things to well. you need a flo control or alos called flo check valve with a circulator installed just for the water heater. ask him for a book on the heater his plans to put in and it will tell you what you want to know. get a another bid and see if you are more comfortable with that guy

  13. #26
    Join Date
    Feb 2004
    Posts
    22
    It appears that i have found a person that is doing what everone is saying. He says i need a smaller boiler than i have and wants to use a munchkin 199K btu modulating unit in conjunction with a super store 80 gallon indirect water heater. I would have a primary loop with a circulation pump and then a secondary loop with 4 separate pumps. One for each zone (3) and a larger one to circulate the indirect tank as well. This pump must be larger he says to make adequate flow. I would then have a control board that would prioritize the zones however i wanted with the tank being priority one. It all sounds good, but the price! However, it appears to be the best offer from someone that knows what he is talking about. I think i have found the man and plan to have him go big on Thursday morning. Thanks to all for your help.

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