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Another Tekmar 260 question

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chrisc
chrisc Member Posts: 3
in THE MAIN WALL
Hello all,
After a bunch of research including a lot of searching on this site. I purchased a Tekmar 260. I have a Burnham Series 2 gas boiler. I have four heat zones with Taco 3 wire zone valves with one taco circulator. I have an indirect Super Stor water heater with a 2nd Taco circulator. This is all controlled by a Taco zvc-406 using the DHW priority.
My concern is a couple of places in the Tekmar manual it talks about turning on the heat circulator when there is not a call for heat. The circulator is on the return side to the boiler after the zone valves. The manual says during DHW post purge it could run the pump as much as four minutes. What good does the heat circulator do if the zone valves are closed? I'm wondering if it makes more sense to let the ZVC-406 continue to control the heat circulator to be sure the pump only runs when a zone valve is open. The Tekmar will still control DHW and outdoor reset.
My second question has to do with the indoor sensor. This is a non condensing boiler so I know I will only get partial reset by keeping the min temp at 140 degrees. The house has four heat zones all kept at different temperatures. I wasn't planning on installing an indoor sensor for that reason. Should I get one and install it in the most occupied area of the house? Thank you for the help.

Chris

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  • JohnNY
    JohnNY Member Posts: 3,230
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    You don't have a system piped well enough to support the functionality of the tekmar 260. That's why you're confused. The indoor sensor isn't likely to help you in this case either.
    You'd have been far better served going with a Taco PC700 control coupled with the ZVC-406...if the ZVC would happen to be the EXP expandable type.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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    STEVEusaPA
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    +1 on @JohnNY
    The DHW post purge is just taking some residual heat out of your boiler and dumping it into the indirect.

    There was an error rendering this rich post.

  • chrisc
    chrisc Member Posts: 3
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    JohnNY and Steve thank you for responding. The ZVC isn't expandable unfortunately. That's why I went with the Tekmar. I understand I won't get full functionality out of it with my system. I did like the idea that it dumps some residual heat into the water tank. The manual says in that situation it will also turn on the boiler pump which I don't think I want to happen. It may not be the perfect situation but is there any reason to think it wouldn't work as an outdoor reset? Thanks again.
  • JohnNY
    JohnNY Member Posts: 3,230
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    It will work as an ODR device, sure. And it will only turn on the boiler pump if the boiler pump is wired to the tekmar, which in this case, it shouldn't be. The boiler pump should come on when the boiler fires as if it were a single-zone system.
    You should probably let the thermostats/aquastat turn your pump on through the ZVC then let the Main End Switch energize your heat demand on the 260. In parallel, wire the power to the domestic hot water pump to the DHW demand on the 260 so that it will override the DHW and give you 180° supply water.
    Baboom. Done.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
    chrisc
  • chrisc
    chrisc Member Posts: 3
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    That is my plan. Thanks for confirming.

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