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  1. #1
    Join Date
    Jan 2012
    Location
    Central New Jersey USA
    Posts
    64

    Radiant heat boiler piping question

    I walked into a small nighmare. I went on a service call to deal with some noise issues with radiant floor heat. I have a Burnham Reliant boiler that maintains 160* at the boiler. The loop piping is not decoupled. What appears to be happening is when one of the zones kick in that have not been operating for some time, I am experiencing a temperature drop of about 35*. This is causing the noise because the boiler is getting a rapid temperature drop and tries to maintain 160*. After it maintains the 160* it sends the hot water back to the radiant zones and causes the temperature at the zone to jump up about 35* before the mixing valve can react. This is causing the noise.

    Is the loop from the boiler supposed to be decoupled? Does anyone have a link they can share that will show me the proper piping and devices that are required to tame this beast?

    Thanks

  2. #2
    Join Date
    Aug 2001
    Location
    Pavilion, NY
    Posts
    2,106
    Decoupled? Is it primary secondary piping?
    ...

  3. #3
    Join Date
    Jan 2012
    Location
    Central New Jersey USA
    Posts
    64
    Quote Originally Posted by kangaroogod View Post
    Decoupled? Is it primary secondary piping?
    Primary

  4. #4
    Join Date
    Aug 2001
    Location
    Pavilion, NY
    Posts
    2,106
    Does this boiler service other zones? Are these other zones baseboard or something that needs a 160 degree temp?
    ...

  5. #5
    Join Date
    Jan 2012
    Location
    Central New Jersey USA
    Posts
    64
    There are 8 radiant loops coming from the supply and return of the boiler. Each have their own pump and mixing valve. The boiler has its own pump and mixing device internal of the boiler. The boiler has a supply pipe and a return pipe, but this piping is not in a continuos loop. The radiant floor zones do not require any more than 140* water. There is no baseboard or heating coils, strictly radiant floor heat.

  6. #6
    Join Date
    Aug 2001
    Location
    Pavilion, NY
    Posts
    2,106
    Interesting configuration..
    First I would not set the limit temp higher than the max loop supply temp. I would also pipe it primary/secondary to prevent thermal shock to the boiler and unnecessary condensing. Primary/secondary will allow boiler supply water to be directly introduced to the return to keep your return temp up. You could go so far as to use. Temkar or taco variable speed pump to inject water into the secondary loop but that may be more than what you need. My thought is that if your loop temp is 120 degrees,,,, set boiler limit at 120 Get rid of the mixing valves all together using primary/secondary. If condensing occurs or proactively primary loop set at 160ish get rid I the mixing valves on each loop and variable speed injection pump to secondary with taco/tekmar to inject 120 into the secondary
    ...

  7. #7
    Join Date
    Mar 2011
    Location
    North Carolina Piedmont Area
    Posts
    448
    Here is some info on Taco. Like Kangaroogod said an injection system works great. If it is a large system you may want to consider a buffer tank.

    You may want to download the design software.
    here is a link:
    http://www.taco-hvac.com/en/embargo_...ionTacoHSS.exe

    Attachment 350361
    5000MixValve(PA07).pdf

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