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  1. #14
    HowiefromAPEX Guest
    Hey Joehvac25, thanks for your input. You're probably right, I most likely am over engineering this, all with the idea of keeping it simple. I figured I could use either a flow valve or a strap on aquastat. I assumed I may need a mixing valve on the hot side.

    If I add a second water heater like you suggest, would it be parallel to the first, or in series, and why do you suggest a mixing valve? Is it for safety, and could I essentially just start with with the temp control valve in the shower set a bit colder, and push it along as needed? I'm fairly sure I mentioned having a baby in the house, so if the mixing valve is for safety, then that makes complete sense to me.

    What you're saying about the boiler needing some time to get up to temp makes alot of sense, considering the amount of water that must be in there. Out of curiosity, if the plate exchanger was installed on the hot side of the water heater, and the circulator/zone controls do not start flowing boiler water until the unit is at least warm, then would it work? I'm rationalizing that the boiler would be up to temp and able to help out, if not take over, by the time the water heater was starting to run cooler. I'm starting to agree about this being unreasonably complex; if I went with a flow valve, then every time someone washes their hands its going to short-cycle the boiler. If I go with an aqua-stat where would it go? It could go on the cold water supply pipe just before the water heater, but that could also cycle the unit unnecessarily. On the hot side it may run the boiler extensively if there is no call for hot water and the hot side pipes cool off. I suppose a flow switch with an adjustable delay, and now we're back to over-engineered.

    Any thoughts?

  2. #15
    HowiefromAPEX Guest
    I agree that Buderus makes a GREAT product, they're also prohibitively expensive. Regardless of the recovery rate, they're alot of money up front.

    t527ed, where was your fathers house (region/climate) how much water was used at one time, and what size unit? I suspect that those answers will result in my situation being more practical to simply add a second water heater. Indirect fired units are still storage tanks, just like conventional water heaters. The only difference is that they're being heated by hot water from the boiler. So if I use enough hot water it is certainly possible to "run out".

  3. #16
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    I would say keep it simple stupid lol. There are ways around everything but I doubt it would be practical doing plate to plate. A mixing valve would allow you to raise the temp on your water heater to say 140, then the valve would mix that warm water with cold water back down to 120 or so. So because you are mixing water you are using less hot water and it will last longer. Parallel the water heaters so they do equal work. An indirect is also a good idea, you would be running more eff than a nat draft water heater and you can still put a mixing valve on it and raise the temp. Like gravity said it needs to be installed right, many people have issues of there house heating when they make water.

  4. #17
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    4,488
    you will never run out of hot water with the buderus. it will also keep the water at temp for a LONG time. Has great recovery rates and a loss of less than 1/4*f per hour

  5. #18
    HowiefromAPEX Guest
    The smallest buderus indirect tank is 32 gallons, and is over $. If my boiler is cold when Started, then I most likely will run out of hot water. On top of that, I can install three additional conventional water heaters at the same price. The ONLY advantage is efficiency, which is the least of my concerns. The smallest brazed plate exchanger from Bell & Gossettis rated at 60,000 BTU with boiler input temp of 180 degrees and output temp of 130 degrees. Not much more complex than an indirect fired unit, a fraction of the cost, and almost no space loss.
    Last edited by beenthere; 12-18-2012 at 07:13 AM. Reason: Price

  6. #19
    Join Date
    Feb 2008
    Location
    Altmar, New York, United States
    Posts
    5,175
    you are right it is the same concept exept the indirect has storage so you won't notice a "laps" in recovery. with the plate exchanger it is being treated as a point of use heater. they used to put domestic hot water coils inside boilers to do pretty much what you want to do. they usually did not work well. aleays ran out of hot water and alot of times it would go from hot to warm to cold and do this constantly. of course depending on the demand. it is your demand why i am not confident with this set up.

  7. #20
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    Quote Originally Posted by HowiefromAPEX View Post
    The smallest buderus indirect tank is 32 gallons, and is over $. If my boiler is cold when Started, then I most likely will run out of hot water. On top of that, I can install three additional conventional water heaters at the same price. The ONLY advantage is efficiency, which is the least of my concerns. The smallest brazed plate exchanger from Bell & Gossettis rated at 60,000 BTU with boiler input temp of 180 degrees and output temp of 130 degrees. Not much more complex than an indirect fired unit, a fraction of the cost, and almost no space loss.
    If it worked they wouldn't make an indirect because they wouldn't sell. It's as simple as that
    Last edited by beenthere; 12-18-2012 at 07:14 AM. Reason: Price in quote

  8. #21
    HowiefromAPEX Guest
    I am also skeptical due to my potential volume required. I found this on the B&G site: http://documentlibrary.xylemappliedw...11/03/6552.pdf

    Its in regards to their plate exchangers, with a section specific to domestic hot water. I know its being done, but without a reliable source to discuss it with, I'm very hesitant. I tried to contact Brazetek a while back, but never heard back from them. I will likely try to contact B&G. I prefer to speak with people that do not have any real interest in me using their product, but I am struggling to find anyone with reasonable experience.

    With that said, I'm still interested in opinions and ideas, although I may just can it and put another standard tank in. I do still need to zone my boiler. With as much theory that bounces around in my thick skull, I will be the first to state the HVAC is probably my weakest area of residential construction. I have never actually installed a zone system. I know I already mentioned the gas fired boiler that heats my house, I also have a ducted central cooling system, with the air handler supported from my third floor ceiling, and the exterior unit on the roof. Both heating and cooling are controlled by the same thermostat. Any suggestions of what systems/controls I should look into? Most important on my priority list is initial cost for equipment/setup. I am very comfortable and experienced with both high and low voltage wiring, so ease of setup is not as important to me.

  9. #22
    HowiefromAPEX Guest
    Quote Originally Posted by Joehvac25 View Post
    If it worked they wouldn't make an indirect because they wouldn't sell. It's as simple as that
    I completely agree. These work amazingly well. The initial cost is very prohibitive, and with a simple or "dumb" boiler like my peerless, it wont be nearly as efficient or impressive, compared to installing it with a Buderus "smart" boiler. If money wasn't a concern, then I would hands down install all Buderus equipment. They are one of, if not the best equipment provider out there for hydronic systems. Lets face it, if money wasn't a factor I wouldn't be here picking at all of your brains, I would simply have the best equipment delivered and installed by someone else. This way, if there are any problems, I can point my finger at someone other than me. Unfortunately money is the biggest factor for me, at least for this particular situation, and I genuinely appreciate all of the thoughts, ideas, and opinions that everyone has offered. It does help.

  10. #23
    Join Date
    Aug 2012
    Location
    NE wisconsin
    Posts
    404
    I don't think the water would spend long enough in the plate heat exchanger to go from about 40 or 50* to 120* I usually see them used to in situations where the water passes through multiple times and 10 to 15* temp rise.

  11. #24
    HowiefromAPEX Guest
    Hi Philjafo, do you see these often, and what are they being used for when you see them? I don't see many of them at all, and it seems that most of the info I can find is in conjunction with wood burning exterior boilers. Being in South Philly in a row home, I really dont think my neighbors will take kindly to me setting up a system like that. Seriously, my biggest problem is that I simply dont have enough real life experience to have a strong opinion either way. I agree that the rate of exchange seems significant for the space, but it wouldnt be the first time I've been shocked. As well, all of the manufacturers offer similar ratings, so this info is coming from somewhere. Have you seen any newer systems with brazed plate exchangers? Have you ever seen a brazed plate exchanger being used for potable water? If so, please give me your honest opinions/experience, both good and bad. If not, then in theory, any other thoughts?

  12. #25
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    4,488
    If you need your boiler zoned then i would do a indirect as well. This would be the perfect time to add a zone panel and pipe everything properly.

    you wont run out of hot water if done properly.

  13. #26
    HowiefromAPEX Guest
    Quote Originally Posted by gravity View Post
    If you need your boiler zoned then i would do a indirect as well. This would be the perfect time to add a zone panel and pipe everything properly.

    you wont run out of hot water if done properly.
    If you're offering to pay for it, I'll HAPPILY install an indirect fired unit. Unfortunately, the cost of an indirect fired tank makes it not practical. No matter how efficient it may be, I still need the actual cash to purchase the equipment.

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