Mixing valve not working

Discussion in 'Boiler Forum' started by mdkline, Nov 23, 2010.

  1. mdkline

    mdkline New Member

    Messages:
    5
    Location:
    New Hampshire, USA
    Folks,

    I am not a plumber or HVAC guy but have just attempted to put together a new system for a house that I am building. The boiler fires fine and the DHW aspect works well too. However I am unable to get the Taco mixing valve to work. When one of the radiant floor zones is calling for heat the system circulator and the circulator for the zones runs but the TACO Motorized mixing valve flashes green continuously which I believe means "Reduced output (boiler protection activated)". even if I remove the electronci controls on the mixing valve and operate the shaft manually I still don't get any temperature rise at the "C" port. I have double checked that all of the manual ball valves are open and believe that I have the air purged from the various zones ( doesn't matter which one I try) but am still not able to get any haet at the "C" port. The boiler loop connecting to the Taco mixing valve's ports A and B does get hot though. The mixing valve is a Taco I100 C3R-1 and I am attaching a diagram of the system ( hopefully using the correct symbols so that real plumbers/HVAC guys can read it!).

    Any thoughts on what the problem is?

    Thanks,
    Mike

    View attachment heating_system_rev1.1.pdf
  2. MAoilTech

    MAoilTech New Member

    Messages:
    25
    Location:
    MA
  3. mdkline

    mdkline New Member

    Messages:
    5
    Location:
    New Hampshire, USA
    Wiring of Taco looks OK

    Thanks MAoiltech,

    I had not seen that Taco diagram. I did not use the Taco 4 zone priority controller that it shows but rather followed the Taco zone valve wiring instructions for daisy-chaining the end switch connections. My DHW is priority ( controlled by the boiler) but none of the zones have priority. I did notice two things on this diagram though:

    Electrical: theydid not connect up a boiler sensor to the Taco Mixing valve. One is supplied with the valve and I placed it just to the right of where the check valve is shown on the .pdf

    Plumbing : I do not have a one-way check valve in the return line as is shown on this diagram placing I did not see such a valve called for on the original mixing valve documentation and placing it where it is shown on this diagram would make it impossible to get the "4- pipe-diameter" maximum spacing" in the return line spacing. I do have the one way check valve built in to the Grundfoss radiant heat circulator ( PZC). Can you explain what the check valve shown on this diagram does? Also the Valve between the Boiler's output and input lines with the "P" on it. Is this a pressure sensing valve?

    I'm not trying to be difficult and disputing any of these items, but am just confused as they were not shown in the original documentation that I used to build this system. Thanks for your post and you have given me a place to look to see if there is some more TAco information that I may have missed!

    BTW: I have managed to get two of the zones working by exhaustively bleeding more of the air out of them.the Third zone ( a two-loop manifold) I have not tried to get working as I have the send and return manifolds swapped on that one and so the flow rate measurement doesn't work. I didn't try to get that zone bled as I know that I need to swap the manifolds and so will introduce more air. The fourth zone is a five loop manifold and I don't seem to be able to bleed all of the air from it despite using flow adjustments at the manifold to close off all of the loops and then bleed each loop individually.

    Thanks Again!

    Mike
  4. mdkline

    mdkline New Member

    Messages:
    5
    Location:
    New Hampshire, USA
    I just tried to see if I could browse that http:www.taco-hvac/uploads/filelibrary area to see if there was some additional documentation that might be of use.... it says that I am forbidden from accessing this area . Even after registering ( as a homeowner ---- sorry I can't lie, I'm not a professional) It still will not let me browse. I guess that explains why I didn't find the .pdf that was posted on my own.

    I do try to read every bit of documentation that I can find before building a monstrosity!....

    Mike
  5. MAoilTech

    MAoilTech New Member

    Messages:
    25
    Location:
    MA
  6. mdkline

    mdkline New Member

    Messages:
    5
    Location:
    New Hampshire, USA
    Thanks for the links

    MAoiltech, Thanks for the Taco library links taking a quick look at them has answered at least some of my questions. It looks like the purpose of the Pressure differential valve is to minimize pressure build-up when only one or two zones are on and thus prevent the increased pressure from forcing closed zone valves partially open. I did also see two diagrams for using a three-way mixing valve with additional high temperature zones ( like what I am trying to do) with the check valve located on one of them in a way that I would be able to implement without violating the mixing valve's "4-pipe dia" requirement.

    The house is located in Deerfield NH. I have been building it for 5 years now on weekends. I'll see if I can get some pictures. The more I read of this documentation the more I wonder about my system having 2 of the "4-pipe diameter" loops. The Lochinvar Knight boiler indicates that it requires one and the Taco Mixing valve also indicates that it's ports need to have that smae configuration... thus I have two in my design.... but I'm beginning to wonder.

    Thanks again,

    Mike
  7. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,316
    Location:
    Maine
    VFD pumping solves a whole lot of problems. Taco, Wilo, Grundfos all make them.
  8. mdkline

    mdkline New Member

    Messages:
    5
    Location:
    New Hampshire, USA
    Pictures of System

    Folks,

    I have added a few pictures. Sorry if the system looks a bit cluttered but I didn't have a very big area to work with. P1020447 shows the overall system. Boiler output is on right by pressure release valve, goes back to wall ( where it T's with one side returning to red Grundfoss system circulator on right and other leg of T goes left), emerging as the slanted pipe on left which rises to the Airscoop. Past Airscoop you hit the T's for the Mixing valve Input first and return second. At bottom of Mixing valve the T connect the returning water from the radiant zones into the mixing valve and also into the main boiler loop. The main boiler loop continues to the right (after the initial two T's for the mixing valve, turns back towards the wall and drops down to enter the red grundfoss system circulator. The tempered output from the mixing valve goes back towards the wall, loops around and goes into the suction port of the green TAco circulator, whose output port goes to the radiant floor zone valve manifold and out to the rooms. P1020446 zooms in a bit on the Mixing valve to show the tempered output. the blue wire is the tempered water sensor input to the mixing valve, and is located on the pipe right after the taco radiant floor circulator as it enters the zone valve manifold. P1020441 shows the detail of the boiler circulators output and return connection T's. Pipe in center is from poiler output. The left side of its T goes to the Airscoop. The right side goes to the Grundfoss system circulator. The right side of the Grundfoss "T" is the returning water from the zones and the main external boiler loop.

    Sorry for the wordi-ness of this but everything is rather cramped and I thought that without some explanations the pictures might be more confusing than helpful. Referring back to my original system diagram along with these pictures and my explanation of them may help to understand what I've done.

    PS: yes the vertical ball valve in center of P1020447 goes nowhere... that will be part of the basement's conventional baseboard heat when I finally get to it.

    Regards,
    Mike

    Attached Files:

Similar Threads: Mixing valve
Forum Title Date
Boiler Forum Boiler pressure reducing valve, pressure relief valve or both Dec 4, 2014
Boiler Forum Leaking Watts 1156F boiler pressure reducing valve Nov 20, 2014
Boiler Forum Any maintenance I can do to my boiler? Also a question if I'm missing a check valve... Nov 16, 2014
Boiler Forum Boiler copper valve identification Nov 16, 2014
Boiler Forum Hydronic radiator balancing valve question Nov 15, 2014

Share This Page