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Taco 0015 speed settings Q

swvawethead Member Posts: 205
edited November 2023 in Radiant Heating
Thought maybe this would be ok as a breakout thread from my other one.

(The image posted shows the isolation valves in off position during power purging after replacing the expansion tank.)

Just fired back up the Buderus with three zones on Taco 0015s
Thanks to everybody's kind and patient help, things
seem to be fine.

Want to ask about the three speeds on the 0015.
They are currently set to low and maintaining thermostat settings.
Heat is reaching all convectors in all three zones.

Zone 1 is for the main floor and splits off in two equal halves.
Any reason not to bump it up to medium speed?
As it is now no problem reaching set temp.

Wondering about bumping up zone one pump to medium.
Or all three to medium.

No idea on the pros and cons of doing this besides heat pushing through at higher flow rate. Will this cause the boiler to cycle on off more often?
Maybe to better to go slow and steady with longer burn time?


    HVACNUT Member Posts: 5,887

  • swvawethead
    swvawethead Member Posts: 205
    edited November 2023
    Thank you - will see if I can make sense of this chart by resurrecting my aging brain.

    I left out a key detail in my OP.
    Zone 1 pipe run is approx equal to Zones 2 and 3 combined.
    And 2 and 3 are very similar in size downstairs.

    Zone 1 and 2 used to be a single insanely long loop that I split up during a Buderus installation.
    Please excuse lack of verse in hydronics terminology.
    Was wondering about bumping up zone 1 to medium speed.
    Or rather next speed up from zone 2/3 setting for the 0015.

    Can the 0015 handle the high speed as set-and-forget?
    It also has the check valve built in.
    Seems to me if high speed settings is called for, maybe better to go with a fixed speed more powerful model?

    Another nerdy question comes up about potential short cycling the boiler but running the 0015 unnecessarily at higher speed.
    But first Q remains the same - bumping up zone 1 to next speed up from zone 2/3.
  • Robert_25
    Robert_25 Member Posts: 533
    Overpumping can cause noise and wastes electricity.  For zone 1, are you getting plenty of heat from the convectors at the end of the loop?  If you are, leave the circulator on low.  If you think the temperature is a bit tepid at the end of the loop try a higher speed.  

    No issues with high speed all the time if that is what is needed for the application.
    Alan (California Radiant) ForbesRich_49
  • hot_rod
    hot_rod Member Posts: 22,468
    Run it a slow as possible to get the job done. Saves electricity, prevents excessive flow velocity, noise, wear in the piping. When you get to design days, if the heat is not keeping up, bump it a speed.

    If you wanted to take it a step further you could develop a system curve. Lay that over the pump curve and it shows you the operating point, exactly where the pump is operating. Ideally the mid 1/3 of the pumps curve for best efficiency.

    Idronics 16 takes you through the steps of developing a system curve
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • swvawethead
    swvawethead Member Posts: 205
    Robert_25 and hot_rod.
    Thank you - some of what you said flew right over my head but I am nerdy enough to attempt to absorb the info. Will start with the simple approach as suggested.

    We are second owner of the house and amazingly ended up with original blueprint with hydronics piping shown.
    First thing was to take to copy shop and run multiple copies.
    Saved tons of time figuring out the runs, especially under the slab.
  • Joe Mattiello
    Joe Mattiello Member Posts: 707
    Call Taco Tech support at 401-942-8000 for help calculating pressure drop across longest zone to properly set 0015 speed. 
    Joe Mattiello
    N. E. Regional Manger, Commercial Products
    Taco Comfort Solutions
  • swvawethead
    swvawethead Member Posts: 205
    Joe - thank you.
    After straightening out the system last week and then a week of spring weather,
    SWVa is back to freezing nights starting tomorrow.
    Been looking forward to letting the gas meter spin away and observe to start with.
    One thing I noticed is the temp at return pipe is much closer to the supply above the boiler after replacing the rusted expansion tank.
    I may have been oblivious to other issues caused by the rusted tank/pressure loss, etc. .
  • swvawethead
    swvawethead Member Posts: 205
    This is nowhere near as accurate as a tapped in thermometer but gives an idea what's up.
    Before replacing the rusted tank, return temp (upper in pic) was much lower.
    Now it's....higher.
    I'll take it for now before splitting hair over Delta T, etc. at some point.
    Have more of these sensors and will add to the last convector pipe heading back to boiler.
    Very interesting Aquasmart controller operating boiler at lower temps and maintainig thermostat settings.

  • swvawethead
    swvawethead Member Posts: 205
    Moving return line temp monitor farther away from boiler and flue, on vertical pipe..