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Normal Circulator Noise/Issue or Potential Problem?

KC1 Member Posts: 12
A month ago I had a new oil boiler (Buderus G115Ws/3) and Indirect Water Heater (Superstor Ultra) installed. After a few weeks of use, the circulator (Taco 007 F5) leading to my indirect water heater started to make a loud buzzing sound. The technician who did the job was more than happy to come out and change the circulator and purge my system, and the sound was gone. Two weeks later the sound came back, installer came back out and purged the system (did not replace the circ), and the sound was reduced by 75% (went from a buzz to a hum).  A week later, the sound is back again.  I have the same sound coming from the circulator leading to my 2 heating zones as well. The last I spoke with the contractor who did the install, he said if the sound starts again, he is going to replace both Taco pumps with a 3 speed pump.  

So here is my question…  

Is this a normal situation regarding the purging of my system and the elimination of air?  We are on the third go around so I am getting a little bit frustrated with the situation.  I have spoken with Taco directly and I have been told that the Taco Circulator should have nearly no sound at all when running.  Is this correct?  Also, in terms of usage since install, there are only two people living in my house (so we have little DHW usage) and we only turned on the heat twice since the install; I am not sure whether our low usage is contributing to the problem.   

Below are some pictures of my install and a video of the sound that I took a few weeks ago before the second purge.  The sound from the pump is currently not as loud as in the video.  In regards to the install, I posted the pictures below to another “help” message board, and a few of the posters pointed out that the Taco pumps were orientated incorrectly and that my circulators were too close to the T Piping (10 diameter guideline), the later, I was told potentially could cause turbulence, which could be the cause of the sound.  A friend of mine who is a plumber said the orientation is done with the terminal box down to make maintenance easier and he had seen a number of installs just like mine in regards to the distance between the T pipe and the circulator pumps work perfectly.

Any help would be appreciated…

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  • Paul Pollets
    Paul Pollets Member Posts: 3,451
    edited October 2012

    The circ pump should not make any noticeable sounds when running. You may have some air still in the system or you have a bad pump. I don't like to wire the pumps with the electrical box upside down, (it can get wet if there's a leak at the pump flange) but that wouldn't make the noise. I notice there are no ball valves under the (2) boiler drains on the returns so it will be hard to do a "power purge" of either zone.
  • KC1
    KC1 Member Posts: 12
    If the problem is air related...

    If it is air in my system, would the air, over time, leave my heating system as it reaches my air eliminator?  This theory makes sense to me, as every time the system is purged the sound from the circulator is reduced significantly.  I guess my question would then be where is the air originating from…


    From what I have read, having a defective Taco pump is a rarity, so I am guessing it is not the pump...  
  • Paul Pollets
    Paul Pollets Member Posts: 3,451
    edited October 2012

    Most air leaves through the air eliminator, but air pockets can exist and must be thoroughly purged at the radiators, baseboard or at the boiler return IF you're set up to power purge. Your "near-boiler" piping setup doesn't allow this.

    Any air pocket not removed by the air eliminator can cause a problem. Sometimes adding a couple of tablespoons of Dawn detergent to a gallon or 2 of water and pumped into the system can collate the remaining bubbles and make air purging slightly easier. (Thanks, Mark Eatherton)
  • KC1
    KC1 Member Posts: 12

    Would there be anything "install" specific that would cause the circulators to make a buzzing sound?

    I was told that a potential reason for the buzzing was that my system does have enough straight piping between the t piping joint and my circulators (see pictures; it was refered to as the 10 diameter guideline). Has anyone heard of the 10 diameter guideline and do heating systems need to follow it?

    The heating system, when hot, runs at 20 psi, so I don't think system pressure is the issue.
  • RobG
    RobG Member Posts: 1,850
    Air in system

    Coud the air eliminator be defective? Purging would get the air pockets out, and then after the purge the entrained air in the new fresh boiler water would cause new air pockets? Just a thought? 
This discussion has been closed.