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Pressure Differential Bypass

_ray__ray_ Member Posts: 6
I'm about to install a Triangle Tube Prestige Solo 175 system and have a question regarding the TT warning to ensure a pressure differential bypass is installed. My setup will be using zone valves (4) with a Taco Bumblebee (Delta T) ECM as the system pump. Indirect water heater will be controlled by a separate Taco 007. In this setup, should I still have the bypass? I understand many of your comments regarding a Delta P ECM obsoleting the bypass, but does the same hold true of a Delta T?

And, if the recommendation is to still install the bypass, must the valve piping match the header size (1 1/4") or would it be sufficient to install a 3/4 bypass in this case, due to the expected low throughput of the ECM when the bypass should be triggered?

Thanks in advance for your help...


  • TomTom Member Posts: 458
    My 2 cents...

    If you are using a bumble bee then you dont need the PDB but, if you are piping it non primary secondary when only one small zone is calling will the pump give the boiler proper flow? If you are primary secondary it should be fine for use bumble bee no PDB.
    Montpelier Vt
  • ZmanZman Member Posts: 3,517

    I agree with Tom.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • SWEISWEI Member Posts: 7,356
    edited October 2013
    $0.02 more

    With an ECM circ (whatever its control scheme) you do not need to worry about deadheading.

    Set the Bumble Bee to a 30ºF ∆T, and the ODR target accordingly to get maximum efficiency.
  • _ray__ray_ Member Posts: 6
    Not using Primary/Secondary

    My plan was to use standard piping, with only the two circulators (System/DHW). I guess I wasn't worried so much about the case where only a single zone was calling for heat, but perhaps a failure case where the pump was running with no open zones (ZV failure, boiler freeze protection)?

    Thanks for the quick responses!
  • TomTom Member Posts: 458
    Food for thought

    Nice point, I never thought about that, I guess you could use an alpha so that if the zone valves dont open the alpha in effect would sense the lack of flow and basically shut down. If you are really concerned about the freeze protection you could wire in a couple of controls that would have the zone valves open when the freeze mode is on and if you went the route of the alpha it would sense the zone valves open and go.
    Montpelier Vt
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