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    finned tube convectors with modcon (11 Posts)

  • mchenry mchenry @ 6:19 PM
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    finned tube convectors with modcon

    I am looking at the energy use of a 7,500 sq ft administration building, and had a question for you folks. The building is heated at the perimeter with finned tube baseboard convectors (rough sketch of layout is attached), and they recently installed a new TT Prestige boiler.

    The day I was there it was 40 degrees F outside and the boiler supply and return temperatures were 186 F and 182 F respectively (with 186 F target). There were high heat complaints throughout the building.  I realize the new boiler is not set up correctly (not set up to run on the outdoor reset curve). My question is if the existing TRVs would be recommended once the boiler program is corrected, or is it better to remove them? The TRVs are located at the end of each FTR run. There is also a balancing valve at the end of each FTR run.

    Any advice on best set up would be appreciated.
  • Noel Noel @ 6:38 PM
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    I'd leave them in

    I would set them to the same temperature so that they would only close when that part of the system started to rise above setpoint, forcing the remaining flow to the colder area.
    This assumes that the temperature sensing part of the TRVs are located so that they can accomplish this.
    I'd balance the manual valves to make sure that the return temps at the end of each fin tube run are pretty close to each other with the TRVs WIDE OPEN.
    Noel
  • SWEI SWEI @ 10:02 AM
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    TRVs with ORC

    In addition to cranking the TRVs wide open, we set the reset curve and balance for ~74F indoors.  After the TRVs are adjusted to deliver 69F they retain some upside range for the cold blooded types.
  • icesailor icesailor @ 12:09 PM
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    What would ever

    What would ever posses someone to put a TRV on the floor of a CI baseboard unit that was originally set up with ODR, and think that it would control the temperature of a room? A control temperature that is 48" to 60" above the TRV?
    If you encounter one of these misthought disasters, you will end up like I did. You are a fool and incompetent because you can't make something work that flies in the face of Physics.
    As a carpenter, 50 years ago, I worked on such a building as you describe, that had ODR with true reverse return and the mains in the first floor ceiling. So, all first floor baseboards were on a slab and down fed. There were zone valves in the ceilings to help control temperatures against South side solar gain. Because people insisted on putting their desks against the Weil-McLain cast iron baseboards, the heating didn't work that well. No one understood the re-set capabilities, and a "Expert" came in and installed early versions of TRV's. Ones they made a special tool to get the bad elements out IF THERE WASN'T WATER IN IT!!. Being down-fed, and no draining capabilities, you can just imagine. Because the heat didn't work well, they replaced the boiler. The heat still didn't work so they changed the boiler again. I changed the boiler and told them that they needed to get rid of the TRV's or make sure that they were wide open and run the system on the Tekmar ODR controller I had installed. Well, the TRV;s were continuously futzed with and I was considered not competent to have made the building warm.
    Whomever put those TRV's on the floor has taken the opportunity to make you look like a fool. Would you install a T-87 or equivalent thermostat on the floor? Would you install it on the ceiling? I thought that thermostats were to control the space level that was being controlled.
    Starting to feel burned out after spending years of fixing others stupid mistakes.
    Oh yeah, and they look so nice with the enclosures off. Until someone else finds the covers and puts them back on. If they will fit. Now, you have a nice little hot house for the TRV to live in.
    This post was edited by an admin on March 22, 2013 12:11 PM.
  • Paul48 Paul48 @ 12:17 PM
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    ice

    I see a capillary tube coming from one of those.
  • mchenry mchenry @ 12:44 PM
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    Thanks

    Thanks for the replies, super helpful.
    Ther is a capillary tube coming from all of the TRVs, but the sensor is just laying in the enclosure!
    Also, I can't attach a pdf to this message (format of pdf not accepted). Anyone run into this?
    Thanks again,
    Henry
  • SWEI SWEI @ 4:13 PM
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    sensor lying in the enclosure

    Belongs the short list of truly cockamamie ideas.  That's worse than having a standard TRV sticking out the side of the enclosure.  How far above the enclosure (but not above an element) could they be relocated?
  • icesailor icesailor @ 5:11 PM
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    That's going: (PDF's)

    That's going along with my conception of a really bad idea.
    What were they thinking?
    As far as a PDF, copy and paste the link to the note, NOT the open PDF.
  • mchenry mchenry @ 4:54 PM
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    sensor lead

    I would say there is only about 12" on the lead.
    Is it possible to put a longer sensor lead or new sensor on these?
    Thanks
  • knotgrumpy knotgrumpy @ 7:41 PM
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    Danfoss

    And probably Honeywell make TRV's with longer tubes.  I am not sure a Danfoss is compatible with the B&G valves, but here is on with a remote sensor and control that can be placed up to 16' away from TRV.

    http://www.pexsupply.com/Danfoss-013G8565-Wall-Mounted-Dial-Remote-Sensor-w-16-Capillary

    Hope this helps.

    Mark
  • SWEI SWEI @ 9:19 PM
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    12 inches

    above the valve, assuming the emitter is not directly underneath, would likely represent a major improvement.
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