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Beckett Aqua Smart Heat Manager problems ... wiring? No low limit ...

Hi again!

Putting in a bathroom in a house where the customers have little to no hot water at random times. EFM boiler, domestic coil, retrofitted to NG, one zone. The aquastat is set for low limit 160 and high limit 180. Both set with a 10 deg diff. Flow from domestic hot water is good. I suspected scaling of some sort on the coil but when the water is hot it's HOT and flows well. Today I was using a sink and alas I experienced the 'no hot water' issue. I checked out the boiler and the temp is 90 degrees! Uh ... what about the low limit? So I had a look inside the heat mgr and the wiring seemed unusual. Very simple set-up. Line in, circulator, and burner. Line in and circulator look correct. But the burner ... The hot is under the same screw as the line in, not under B1. The neutral is B2 (normal). But the ground from the burner is under the B1 screw. This makes no sense to me. Am I missing something? Have you ever .... ? I imagine the burner isn't being started by the control because the hot wire isn't under the B1 screw. It does fire but when is it getting the message to fire? Any thoughts appreciated. Thanks.


  • pemelch
    pemelch Member Posts: 1
    The burner fires when B1 is powered. The conversion gas guns require a constant hot, it sounds like they used the ground instead of running another wire. It sounds like you lost your LO limit on your aquastat and the boiler is only firing with a call from the thermostat. You can test it by taking the boiler temperature below LO limit and removing the call for heat from the thermostat. If B1 is not energized on the aquastat when the boiler temp is below LO limit and no call from the thermostat, replace the aquastat.
  • icesailor
    icesailor Member Posts: 7,265
    The Beckett Aquasmart is like the Honeywell 71 series control.

    Most of these burners use some sort of electronic control as a safety for the burner like a Carlin 602000. It has to be powered at all times so it knows what to do. Usually, there is a red wire with a white tracer that needs to be powered at all times. Then, B-1 on the Beckett powers from the black wire on the burner controller. Some folks have tied the black and the red together and used B-1 to power the control. It really screws up the control. You will not get any Post Purge because there is no power to the control after B-1 opens at the end of the call.

    Sounds like Sparky doesn't understand the interaction between controls and how they work.

    Sparky might have lunched the control with that green wire under B-1. The Beckett Aquasmart installation wiring diagrams don't show any powering to the controller and being live all the time. Its in the controller wiring diagram. You're supposed to RTFM.

    On oil boilers, with the swing open door to get at the chamber for cleaning, they have a disconnect plug. It has four wires. A Green (Ground) white (Neutral) Black (From B-1 on the controller that gets powered on a call for the burner to run) and Red. Constant hot. Even on a BAB like a Carlin 950 CRD, it's the same. The control needs constant power, and it gets it from a separate wire, hot all the time, after the service switch.