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Luke warm shower this morning.

Good Morning,

Every 2 weeks we have my mother in law stay with us and at about 5am we will have 2 showers for about 10 minutes, then at 5:30am another single shower. This morning was the first day we had this many showers for this visit, while heating the house, and the water wasn't hot. Last Feb and Mar we were able to repeat this, but we had hot water for both showers. I had the later shower and right after I got out and got dressed, I went to the boiler and it showed Domestic and Central were both ON. I had the boiler annually cleaned about a month ago and I'm wondering if any settings or anything was changed. We have a Burnahm Alpine ALP105 and a Taco SR503-4. The Taco has 3 central heating zones. We have a 40gal Ultra Storage tank. When I get home tonight I can get some drawings for how the Taco and Boiler are wired, but as I recall, each of the 3 zones are directly wired to its own thermostat. The Isolated End Switch terminals have wires, but I haven't confirmed where they land on the boiler.

Thank you,


  • SteveSan
    SteveSan Member Posts: 157
    Good morning Joe, please call into Taco Tech Support 401-942-8000 just ask the operator for Tech. We are here Mon-Fri 8am-5pm.
    Erin Holohan Haskell
  • GBart
    GBart Member Posts: 746
    Your indirect needs to be on zone one and the board configured to priority, see install instructions attached or call Taco above

  • rick in Alaska
    rick in Alaska Member Posts: 1,396
    Actually, it is zone 3 that is the priority zone on that control. But even with it not set for priority, a 40 gallon indirect should still be able to do a few showers, unless they take long showers like I do, but even then it should go a long time.
    Maybe you could post some pictures of the piping arrangement around the boiler and to the water heater.
  • xxjoeyxxeb
    xxjoeyxxeb Member Posts: 4
    A few pictures are attached. I cannot have the indirect on Zone 3 because I have 3 central heat zones. I don't recall having this issue last spring when we were in extreme cold and running 2 showers. They may not have been HOT showers, but I don't recall them being near COLD. I believe the first person who enters the shower takes them long and hot, which runs it down for the person who brings on shower 2 (near the middle of person 1's shower). I ended up being person 3, about 10 mins after both and it was WARM. Right after, I went downstairs and I believe my Central and Domestic were all running. I read somewhere about tying in a single wire from the boiler to Zc on the Taco... Not sure if that's my ultimate solution so the Central pumps stay off?

  • xxjoeyxxeb
    xxjoeyxxeb Member Posts: 4
    Note: Pictures above of wiring are during construction from last winter. I will get an up-to-date wiring picture later today.
  • GBart
    GBart Member Posts: 746
    The manual I downloaded shows zone 1 as priority but the pics clearly show zone 3, you have to switch the wiring completely from the zone thats HW now with zone 3 and enable the priority, you switch the tstat and circ wires so that they are still together, take pictures FIRST and mark the wires just IN CASE
  • hot_rod
    hot_rod Member Posts: 18,263
    looks like you are running the DHW circ from the boiler and zone circs from the relay. If so, when you have a DHW call you need the boiler to communicate that to the relay box to drop all heating circulators off.

    A four zone relay box with the DHW on the appropriate output, might be the easiest fix.

    To avoid confusion the Caleffi relays have DHW on zone 1 always regardless of the version you chose :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    rick in Alaska
  • xxjoeyxxeb
    xxjoeyxxeb Member Posts: 4
    Two questions I have are:
    1) Why does the Taco wiring diagrams show either a jumper on Zc/Zr OR wires going to the boiler?
    2) Why does the Alpine Burnham wiring diagram show 1 wire from Zc on a Taco to Sys Circ on TB1 on the boiler?

    Mine has nothing on Zc/Zr. Maybe I need that wire from question 2 to tell the Taco to stop a circulator?
  • GBart
    GBart Member Posts: 746
    You have to get the indirect on the priority zone, if you don't IF you are calling for hot water and then you call for heat on another zone you will suck that indirect COLD, you will literally be using it to heat the house.