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wiring aquastat to Taco SR506

Dave F_2Dave F_2 Member Posts: 15
How would I know if the boiler burner could run on line voltage? I guess I'd have to call the manufacturer (Lochinvar EBN 300)?


  • Dave F_2Dave F_2 Member Posts: 15
    wiring aquastat to SR506

    We have an Ergomax reverse indirect water heater that we are also using as a buffer tank for our heating system. All individual zones pull off tank.
    We have a Taco SR506 relay switching pump controller that controls all our 5 individual zone pumps.
    The way our system works, whenever any zone calls for heat, the individual zone pump runs as well as the boiler circulator which is wired across ZR and neutral on the SR506.
    I want the Ergomax aquastat to be able to turn on the boiler when the tank temperature drops below the aquastat setting. No other zone thermostat would trip the boiler (just the ergomax aquastat).
    We have an extra set of contacts on the top area of the SR 506 for one other thermostat/switching device.
    I want to wire the aquastat in parallel to that extra set of contacts.
    In other words, I would run a thermostat wire from the Ergomax aquastat to the 6th input slot on the SR 506. Then I would run another thermostat wire from the same set of input contacts on the SR506 to TT on the boiler.
    Then when the Ergomax calls for heat, it would run the boiler pump as well as trip the burner on the boiler.
    Since there would be no individual zone pump for the Ergomax, it would only turn on the boiler pump. All other zone pumps would also trip the boiler circ when running.
    But the Ergomax would be the only thing to turn on the boiler. Since the aquastat has no voltage (it is basically an on/off switch), is there any problem with wiring it to the SR506 input as well as the TT on the boiler in parallel?

  • Empire_2Empire_2 Member Posts: 2,343
    Priority Zoning

    This is what you are looking for. If I read you correctly, you want the tank (when it calls) to bring on the boiler to serve the DWH. Priority zone would first cycle the DWH and when done, allow the other space sones to be served. If that's what you are looking for there is a Taco control that incorporates this into to board. You may even have the fight one, but I cannot confirm this. I do not have the manuals. might help further.
  • Empire_2Empire_2 Member Posts: 2,343
    Taco 506

    I just checked out the web sight and it does accomendate priority zonning. Check your manual. Will tell you how to wire the control.
  • Dave_61Dave_61 Member Posts: 269

    The SR506 does accomodate priority switching. However, we already have a Phase III on that zone for DHW. Currently, we are just using the ergomax a buffer tank but will probably pipe it to preheat the water for the Phase III.
    If I put the Ergomax instead of the Phase III on priority, then if we were pulling off the buffer tank with our individual zone pumps to heating zones and the Ergomax called for heat, it would shut the heat off to the zones by shutting off the pumps. Would that be an issue?
  • Empire_2Empire_2 Member Posts: 2,343

    You have to decide which device you want as priority. If the Ergomax calls in conjunction with the DHW, the Phase III should shut down until the DHW is satisfied which should not take long. Since this is not such a long time in Zone pump shut down, that's what it's all about. Normally when we use priority controllers we want the space zones to shut down, cause afterall nothing feels worse than a shower running out of water. I think I Understand what you are doing so see if this makes sense.
  • Dave F_2Dave F_2 Member Posts: 15
    I'm not sure if

    we're on the same wavelength....I am only using the Ergomax as a storage/buffer tank for our heating. It was an add-on to our oversized low mass boiler which was shortcycling. We still use the Phase III as our DHW source, which is piped as one of the zones that come out of the tank. The boiler pump, which circulates between the tank and the boiler must run when either the buffertank or any other zone is calling for heat.
    Eventually, I would like to pipe our DHW through the Ergomax, but currently it is just a storage tank.
    Do you think (if we put it on priority), adn it's a cold day with our 3 sir handlers all pulling out of the buffer tank, that we will see a problem if the 3 air handler zone pumps stop running while we reheat the water in the Ergomax?
    It holds 72 gallons of water.
  • Empire_2Empire_2 Member Posts: 2,343

    Call me at the office. Here till about 2:30EST.716-648-1763 Empire Mechanical. Mike
  • Dave F_2Dave F_2 Member Posts: 15
    Hey Mike,

    The boiler control is made by UT Electronic from Huntington, IN. It is model 1013.
  • superMARKetsuperMARKet Member Posts: 86
    I wouldn't do that

    You've got a transformer on the burner, and you've got a transformer on the 506, and you really don't want the two to touch. Yeah, you can make them touch if you're really careful and you know what you're doing, but it's not a fantastic idea, and I can guarantee that neither control wasn't tested/isn't rated for that configuration. So keep the burner's T-T away from the 506's T-Ts.

    But here's an idea: can you cycle your burner on line voltage? Why not use the sixth pump relay on the 506 to drive the burner? You'd jumper T-T on the burner's primary in this case. When the aquastat calls, the 506 would turn on the burner as a line voltage device, and it would bring on the boiler circulator too. You wouldn't use priority in this scenario.
  • Dave F_2Dave F_2 Member Posts: 15
    boiler control locked out

    I noticed the house seemed cool. I went downstairs and gas boiler wasn't running. I opened the panel ,and the light that says "purge" was flashing.
    I switched off boiler to reset it, and it immediately came back on and heated up to temp.
    Lster, the same thing happened. No heat and "purge" light flashing.
    I know our boiler goes through a prefiring purge and post firing purge.
    The only thing different about the system is that we had changed how the boiler is tripped at the TT connection from the individual zone thermostats to our Ergomax aquastat. Could that have anything to do with this?
    In what scenarios would the postfiring purge be interrupted electrically (boiler shut down prematurely)that would cause panel to lock out?
    I rewired everything the way it was, and no more problems since last night.
  • Empire_2Empire_2 Member Posts: 2,343
    Hey Jim

    Just a thought, Maybe the pre-purge was short cycled upon starrt up off the ergomax. Boiler sensed a fault and locked out. Make sure the diff on the ergomax is at least 5 to 10 *. ALso read the manual. They usually give senerios as to why certain error codes are displayed. Also, do you have another name on the boiler? I have no idea who this manufacturer is.
  • Dave F_2Dave F_2 Member Posts: 15

    The manufacturer of the boiler is a Lochinvar. Unfortunately, the manual did not say anything about error codes/scenarios.
    Here is what I think happened.....
    The boiler pump only runs in current wiring when any zone calls for heat through the SR506. The Ergomax is wired across TT on boiler but does not start boiler pump in current scenario.
    I thought that in winter Ergomax would only call for boiler to start if zones were running.
    Last night, when setback thermostats started shutting down for the night, I have a feeling boiler was running to heat Ergomax. Once the last zone pump stopped running, the boiler pump shut down through the SR506.
    Because of that, flow switch in boiler piping shut off boiler probably before postpurge finished and liocked out panel.
    What do you think?
    I rewired things through SR506 (at 11:30 last night!) so that Ergomax no longer calls for heat.
    The TT on the boiler is now wired through SR506 so that boiler/boiler pump are bnoth tripped by endswitch on SR506
  • Empire_2Empire_2 Member Posts: 2,343
    Yea, I could see that

    But, why wat it telling you a purge problem. Wether the cycle is short or cut off the boiler see's it as a termination of a call. Either way it should post purge. I guess I'd like to actually see what you have. WHere are you? I need a vacation anyways...:)
  • Dave F_2Dave F_2 Member Posts: 15
    I live in CT.

    I alled Lochinvar, and they said what you said....that even if the pump stopped, the boiler would still postpurge. Everytime I reset the boiler, it started and ran to temp, so there was no issue with prepurge. I'm wondering why it would prepurge but not postpurge. Currently, it seems to be running fine. I'm just worried if it craps out while we're away. I'm having the gas co guys out to look at it today.
  • carol_3carol_3 Member Posts: 397

    incredible chain of messages, guys. What did the gas do say?
  • Dave F_2Dave F_2 Member Posts: 15
    The gas co

    guys said that everything was running fine, but they replaced the air pressure switch anyways.
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