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Taco SR501-4 Switching Relay dilemma

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lmanc2222
lmanc2222 Member Posts: 13
I wired a Taco 501 switching relay exactly as described on the schematic and when I jumped T to T to run the circulator I got a loud pop instead from the relay control. I can't see any damage anywhere, no fuses blown but something popped. It was loud and right around L1 and L2 terminals. My first guess was that maybe the circulator shorted out because that's what would have come on first but there is also a warning on the schematic that there's a danger of having two feeds. I can't have a feed to the aquastat and have another to the relay. The relay voltage must come from the aquastat but how do I do that? I took power from where the aquastat gets it and ran another bx to the relay. I don't get it. HELP!
How do I even troubleshoot the control without blowing it up? Hmmmm...

Comments

  • Alan (California Radiant) Forbes
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    Can you make a drawing of how you wired it to show us?
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • HVACNUT
    HVACNUT Member Posts: 5,861
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    Which aquastat did you get power from and what terminals did you wire to?
    Cold start wiring:
    2- neutral
    1- 120v hot
    3- supplied jumper to 1
    4 N.O.- to circulator hot
    Neutral from circulator to terminal 2 on the 501.
    If you have a tankless coil, its a bit more involved. Post some pics of the 501 wiring, aquastat, and boiler.
  • lmanc2222
    lmanc2222 Member Posts: 13
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    Here we go, Gents. This is how it's wired and POP! Interestingly enough a friend noticed that the TT and RW terminals are shared. If I were to wire for low voltage and I jumped RW thinking it was TT I would have blown the transformer. This I know. Low voltage wiring is the drawing on the right. I wired for line voltage with a tankless coil, which is the center drawing. Check out the warning! The relay is wired to the same feed as the aquastat. Does it need to come off another terminal on the aquastat? Taco says no, just stay with the same phasing as the aquastat sees.
  • lmanc2222
    lmanc2222 Member Posts: 13
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    Jumper is removed on H terminal too.
  • Jamie Hall
    Jamie Hall Member Posts: 23,428
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    Ah... is there a reason you have a separate 24 VAC supply for your thermostat? The odds are excellent that you have the phases reversed in there somewhere... hard to say what's blown, but I dare say something is. Probably a relay.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    SuperTechlmanc2222
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    You showed us a wiring diagram, which of course is correct, but it doesn't mean you wired it exactly like that. I'd triple check everything.
    I'd also check out the relay with a meter, make sure what is NO is normally open (no power of course), and what is NC is normally closed. I wonder if ZC & ZR are backwards.

    There was an error rendering this rich post.

    SeymourCateslmanc2222
  • Jamie Hall
    Jamie Hall Member Posts: 23,428
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    As a further note, only the third diagram provides for a 24 Vac powered thermostat connection, and only to those two terminals. T-T cannot be jumped in that configuration. You can't mix wiring diagrams.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    lmanc2222
  • lmanc2222
    lmanc2222 Member Posts: 13
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    Rest assured the relay is wired as shown. I checked it 5 times with a meter before powering up. Hence, the post on the wall. Thank you everyone for your thoughtful help. Thank you.It remains unresolved for now. I'll need Taco to hold my hand. I did not check the isolated phasing as suggested. I'm pretty sure both feeds are the same feed from the panel. I'll open the box once again. Ugh.