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Sales Associate - Taco 595 thermostatic bypass valve

TimKTimK Member Posts: 5
Anyone have any suggestions on repiping or replacing a Taco 595 thermostatic bypass valve?


  • icesailoricesailor Member Posts: 7,265
    What do you need to know?

    What's the problem? Why do you need to re-pipe it and what is the current valve doing now?
  • TimKTimK Member Posts: 5
    Taco 595

    Element is sticking
  • icesailoricesailor Member Posts: 7,265
    edited December 2011

    A quick romp around the Web finds that that valve may not be made anymore and was problematic. There are better ways to do what you are probably doing,

    Are you using it to control potable hot water or using it as a hot water extender?

    Take the cartridge out and soak it in white vinegar. Then, carefully clean the scuz out of the barrel where the cartridge slides.

    Or replace the valve.
  • TimKTimK Member Posts: 5
    Taco 595

    The valve is used as a hot water boiler bypass with a thermostatic element that begins to open at 150 and is open fully at 180, diverting hot water directly into return and ensuring some degree of protection from thermal shock.  I can see how it can be re-piped with ball valves and or 3 way diverting/mixing valve.  I wanted to stay away from temperature modulating valves.  I just did not know if someone had more experience with these devices.
  • icesailoricesailor Member Posts: 7,265
    edited December 2011
    Mixing/Low temp Water:

    I don't know what you are trying to do but if it is an oil boiler, 140 minimum boiler temp will stop condensation. If gas, 120 or higher.

    I put a Taco "I" series 4-way mixer on a system. You won't get any shock with that and the valve controls all the operations itself. And you can use outdoor re-set and still protect the boiler from thermal shock.

    What is so unusual about this system that thermal shock is an issue?
  • Joe MattielloJoe Mattiello Member Posts: 547
    595-1 by-pass valve

    I did some research on the replacement thermostatic assembly we offered for this valve. We stopped offering the element back in 2005.  For your reference I attached a piping schematic showing the 595 installed as a by-pass.  The objective was to keep the boiler hot minimizing thermal shock, and condensate.  It was originally engineered for Burnham Boilers back in 1982. The Element, procured from The Dole Valve co, of Illinois part number BN-28235-1 was a purchased item we used in our 595-1 valve.  

    To facilitate the piping I suggest pulling out the element throwing it away, and put the cap back on.  Install a ball valve, or gate valve in the by-pass line running from the return line back into the boiler.  You can throttle the flow using the throttling valve to redirect some hotter water back into the boiler.  It will obviously be a manual flow control, as opposed to the thermostatically control flow.  Hopefully this helps.  If you have additional questions or concerns give me a call. 
    Joe Mattiello
    Application Field Service Engineer
    Taco, Inc.
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