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Has anyone used the Taco X-Pump Block?

Steve EayrsSteve Eayrs Member Posts: 56
but never with steam, so can't answer for your exact application. Worked great for the small radiant, and one s/m I used them for.
The 510 tekmar is a great choise in m opinion. We use a lot fo Tekmar, but usually complete controls, injection pump mixing, etc., and a lot of TN4 stuff.
The Taco control on the mixing block is actually something Tekmar makes for them, and takes care of the mixing, outdoor reset, etc, and the 510 and 079 sensor should match up great.



  • PhilPhil Member Posts: 172
    Looking for advice or experience with using the X-Pump

    I am (slowly) renovating an 1830's farmhouse and have gotten around to creating a new 160 sft bathroom on the second floor. I've done my heat-loss calcs and come up with 16-18 btu/sqft. I am using WarmBoard with ceramic tile. One loop for the whole floor, about 140 ft of pex-al-pex. I've calculated max water temp to be about 90. In the basement I have a new MegaSteam from September (very happy with it) which was piped with valves to facilitate hooking up the required HX, pumps, etc. for the new radiant zone.

    Any thoughts on using the X-Pump in this application? It looks like a nice simple package which would require very little additional hardware (exp tank, air eliminator, over-pressure, isolation, and fill-drain valves). My primary concern is with the desire to get the source-side pump as low down to the floor as I can get it, and whether there might be some other reason that makes this a bad idea that I've missed.

    Thanks in advance,

  • PhilPhil Member Posts: 172
    Also looking for thoughts on thermostat

    I am planning to use a tekmar 510 with the 79 floor sensor. Any thoughts on that selection?

  • Dave StromanDave Stroman Member Posts: 759

    I used one for a one room radiant floor job. Used the water heater as the heat source. Worked beautifully! I do not think you will want to pump the condensate from a steam boiler through that flat plate heat exchanger. Will probably plug it up.

    Dave Stroman
    Dave Stroman
  • Dave,

    If he used a wye strainer & mixing valve, could he not achieve the temp he needs from the steam boiler water?,,, just curious.

  • Dave StromanDave Stroman Member Posts: 759

    When you use a steam boiler in this way, you are pulling the water from the bottom of the boiler. Lots of sludge down there. Per one of Dan's article's, you should use a bronze pump with a large inpeller so it will pass all the junk right through it. A strainer will just plug up causing pressure drop and the pump to cavitate. See this link-

    Try using a small indirect water heater. Pump the boiler through the coil and set the aquastat to the desired tank temp. I have used this for radiant floor jobs and it work perfectly.

    Dave Stroman
    Dave Stroman
  • kpckpc Member Posts: 20
    these are all....

    good ideas....but...if it's only 160 sq. ft. would not electric mat be more cost effective? Or if you have the tube already in..a small electric water heater. set the heater to 95 and you are done....just a thought.
  • PhilPhil Member Posts: 172

    The megasteam supplies a tapping for indirect circuits which is just below the nominal water line. I currently have an indirect providing DWH using this supply (the returns are merged after the hartford loop), and this setup has been working great. The people who installed my system left additional isolation valves on the supply and return for the radiant zone so the connections would be easy. I understand that there is a big difference between a flat plate HX and the large coils in the DHW tank, but do you still think this will be a problem if the boiler water is coming from the top instead of the bottom?

  • Dave StromanDave Stroman Member Posts: 759

    The only thing I can say is the passage ways through a flat plate HX are pretty small.

    Dave Stroman
    Dave Stroman
  • SteveSteve Member Posts: 546
    Why take a chance?

    Use a plate exchanger off the DHW side of the indirect.
This discussion has been closed.


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