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Banging Danfoss valves

JK_3
JK_3 Member Posts: 240
Hello everyone,

Its been some time since I have been here and I hope that everyone is doing well and had a nice Thanksgiving. I recently installed 2 danfoss trvs on an existing hot water baseboard system ( this is a makeshift venturi system that was improperly installed by others)and they both (at different times) bounce. They will start bouncing open/close so bad that they shake the whole system. They don't seem to stop until I turn them to the full closed position. when I turn them to the open position they will bounce again unless I open them very slowly. I also found that if the pressure on the system above 22psi to help purge the system while they are closed that they will not open unless I lower the pressure first. Has anyone one else experienced this and does any one have any ideas why this may be happening. I will be re-piping the entire system in the spring but I am trying to get them through this winter. Any input would be appreciated. 
Life is Good !! Enjoy it !!

Comments

  • kcopp
    kcopp Member Posts: 4,419
    maybe a ...

    silly question... are they in backwards?
  • JK_3
    JK_3 Member Posts: 240
    That was my first thought

    That was the first thing that I checked when this problem started. They are installed on the supply side of the baseboard with the arrow facing the basebord with the flow.
    Life is Good !! Enjoy it !!
  • kcopp
    kcopp Member Posts: 4,419
    give us more....

    info. Circulator size/ model.?  Pipe run lengths?  It is a newer system or real old? Did some junk brake loose and foul the seat? Any Pix?
  • JK_3
    JK_3 Member Posts: 240
    edited November 2011
    Here is more info

    This is a brownstone. The "professional" that installed the system did pump away using the Taco  007 that came with the boiler and installed the expansion tank facing the right-way, everything after that is questionable to dead wrong. I am just trying to get them through the season so that I can install a completely new system in the spring. The supply is 1 1/4" splitting into (2) 1 1/4" lines after the circ.  The front of the building line goes straight up and at the first floor tees 1 1/4" x 3/4" to supply that floor then continues 1 1/4" to the second floor where it tees 1 1/4 x 1 x 3/4 to feed that floor at the third floor it tees 1 x 3/4 x3/4 to feed the third off the bull and the forth off the run. The rear of the building is the same except that it runs 35' through the basement before going up. The returns are exactly the same as the supplys. Each emitter (8) is controlled by a TRV and the system is controlled by a t-stat on the first floor. I have not done my heatloss calcs yet but I am pretty sure that none were done and I am absolutely sure that the boiler was not sized to the radiation or the building needs. The t stat has to be set high enough to heat all floors and as TRVs close the upper floors can get heat If all the air is out of the system( I have still not gotten all of it out). When the last TRV closes the system can still be running and pumping to nowhere (no pressure diff by pass). If 1 TRV opens with very cold water in the emitter There is massive banging for a few minutes (180 meeting 70). But I still cant figure out why my new TRVs are banging even with cold only in the system. Please remember that I am just trying to get them through this season.

    I intend to put air eliminators at the top or the return risers and on the ends of each emitter for a temporary solution.
    Life is Good !! Enjoy it !!
  • icesailor
    icesailor Member Posts: 7,265
    Bangers:

    It's hard for me to visualize this piping picasso but it sounds to me like your common, over pumped nightmare.

    For those of us who like to figure things like this out, "I" would be looking for a boiler drain (s) on the end of the mains out in the gombee weeds somethere where I could screw a pressure bypass and connected the supply and return sides with the by-pass with washing machine hoses and see if it improves or stops.

    There are a lot of overpumped hydronic systems. And a lot of installers who don't understand the difference of pressure in a heating system and pressure in a potable water plumbing system. They are similar, but not the same.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    the ONLY time I hear them hammer...

    Is when flow through them is reversed (backwards install). If installed properly, and the pump is oversized, the usual complaint is a high pitched squeal or hiss as flow is being forced through them. By the way, that is one of the biggest complaint from German hydronic heating system owners. Excess noise due to oversized pumps, and something like 70% of those people surveyed (7 years ago) were NOT happy with their systems. (Source:WILO)



    Shock and surprise eh...



    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
This discussion has been closed.