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Triangle Tube Indirect vs HTP SSU Indirect

I am going through the process of building a new house and have suggested to the builder and their plumber that we use the HTP SSU80 in conjunction with the HTP Elite FT220 boiler.  The builder's plumber says the Triangle Tube Smart 80 is a better more efficient water heater.  Is this true?  Which products are the best?


  • icesailor
    icesailor Member Posts: 7,265

    This may not pertain to you but it did to me and maybe some others.

    Triangle Tube indirects and Super Stor SSU's are both wonderful things.

    But written deep within the instruction manual is a little part about filling and draining the Triangle Tube tank. When filling the tank for the first time, fill the domestic tank first, then fill the boiler side. When draining the tank, drain the outer (heating side) first, then the domestic potable water tank. Because it is a tank within a tank, if you do the opposite, the inner tank can float up and break.

    In my case, I had numerous houses where the water was drained. If the heat is left on, you can not drain the potable water out of the tank or it will break. If yiou turn on the water, you must fill the potable water tank side before you fill the boiler side. Not everyone is aware of this fact.

    SSU's have a inside coil that don't have this problem.

    Getting the water out of a Triangle Tube potable water side is complicated, You must be able to dray a good vacuum. Read the instructions and you will see that there are special instructions for Massachusetts installations. A separate dip tube with drain that goes into the top of the tank. It is not supposed to be connected to anything else. So you can draw the water out of the tank. The tubes are often found in closets, uninstalled. Because no one read the instructions. When draining houses, you have to leave both tanks filled with water unless you drain them both in the proper sequence.

  • SWEI
    SWEI Member Posts: 7,356
    edited February 2014
    Hard water and high demand rates

    are where the SMART indirects really shine.  Turbomax handles high demand applications quite well; on hard water the SMART still outperforms the field by a wide margin.

    Other caveats:

    The stainless used for the inner tank does not like high chlorides.

    The carbon steel outer tank is not compatible with open systems (most outdoor wood boilers, many drainback solar systems.)

    The issues Ice ran into above are a side effect of that portion of their design which allows them to mostly ignore hard water.  Make an informed choice.
  • matt_sunwaysolar
    matt_sunwaysolar Member Posts: 61
    Better Heat Exchange w/ Triangle Tube

    The other benefits of the triangle tube tank are that heat (btu's) are allowed to go where they are most needed because the entire outer shell is full of "boiler water". If the entire inner tank is depleted, it can recover much faster as it doesn't rely solely on stratification from bottom to top of tank (like the HTP SSU Tank). Additionally, the heat exchange surface is quite a bit larger because the entire surface of the inner jacket is the HX. The HTP SSU HX's are fairly small.

    The post above is correct. Care must be taken when draining/ servicing the Triangle Tube tank.
  • icesailor
    icesailor Member Posts: 7,265

    I wasn't comparing the two. Just a point that very few know about because of institutional lack of reading instruction manuals.

    Like "Why is that blue plastic dip tube in the closet with the drain on it? What was it for?

    I was only pointing out something that some one might not be aware of and might remember reading something  about it somewhere.

    Like that minor part about the order of draining and filling the tanks.

    Do it wrong and have a problem at your own peril.
  • Plumdog_2
    Plumdog_2 Member Posts: 873
    Which is faster?

    Last summer I replaced two indirects in nearly identical circumstances. Both were tied to Crown Induced draft boilers of 150,000 btu input Both were pumped with 1 inch supply (180 degrees) and return. The new Smart 60 took 31 minutes to get from 55 degrees to 125 degrees. The new SSU 60 did it in 17 minutes. Not pure science, mind you. Just sayin'