Hot water recirculation pump is brown (not black) and pumped directly back into the cold water return line.
This old brown pump came with the house (also an 006) but did not pump. I replaced this one with a different Taco 006 that includes a temperature sensor. The new pump worked, however, it broke the flow control switch in the boiler!
The boiler system has been recalcitrant at best, that is if I may anthropomorphize it a bit. I have joined the ranks of POEM as described by Garrison Keillor. (Professional Organization of English Majors–in case you are not a lifelong fan.) And an English degree allows for a high tolerance for reading directions, not necessarily impeccable grammar and spelling. But reading directions only goes so far. Many years ago I worked with a wonderful volunteer retired lady in the school library of our small town, Spencer, Indiana. Inez used to say that education costs money, one way or the other. And in fact I was willing to pay for the education I needed to install and recommend a radiant system. I have been getting that education one way or another and paying for it.
You might recall the exultation of hot water in an earlier post. I broke the boiler in the next step, putting in a recirculation pump to keep the water in the structured plumbing system warm at high use times of the day. The Taco 007 recirc pump was recommended for recirculation in the directions, however, the flow control in the boiler immediately stopped working upon having water pumped into it. The Taco 006 is similar to the 007 but it can overcome a larger amount of head pressure and does not pump as many GPM as the 007. The 006 is 1/40 HP while the 007 is 1/25 HP so the 006 should not have overwhelmed the boiler flow control.
I ordered a new flow control switch but it didn’t seem to work. Unfortunately one of the times I installed it, I put it in upside down which support told me would break it. So I just ordered another one, not being willing to accuse someone of incompetence, other than myself. Triangle Tube support generously recommended a bypass test to see if the flow control was the issue and after jumping it, the boiler went into an error code for the temp sensor. Another expensive part later the boiler was back to work heating our hot water. Since I only work on the house one or two weeks out of every month, this was a months long process. In the meantime, the radiant heat side of the boiler was also giving me fits.
I should mention that the recirc is now up and running. I realized that flow controls break if there is too much water pressure, which the pump obviously provided. So I bought a pressure regulator and also raised the pump above the water return. At first I had the pressure regulator too restricted. An interesting thing about these devices is that the pressure increases as the screw is loosened, and decreases as it is tightened. So I had to allow a higher pressure through the line to get the boiler to have enough flow to turn on. But now the recirc works great. It has a built in temperature sensor so it regulates itself and I put it on a timer so that it only runs four times a day, when we are likely to need hot water at the tap.
UPDATE: I replaced the timer with a remote controlled receiver and a remote. Now the water only circulates for the few minutes before we get into the shower. We have a 3-5 minute wait, but that is so much better than wasting water.
Skylink Remote Receiver with separate remote.
New blue (not turquoise) recirculation pump.
Water rises a few feet to the pump itself and then falls three feet and goes through a pressure regulator valve before moving back into the boiler. Flow control is working fine. There are shutoffs on either side of this pump too. Have to install these as they allow for repair or replacement of the pump without completely turning off and draining the water system.