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The Glitch:

The two photos below were from the same project. Flow is upward through the vertical pipe in Figure 1. Without any more details being described, can you spot at least two problems in each photo?

The problems and the fixes

Let’s start with Figure 1. Flow through the vertical pipe is upward. The inlet of that circulator is only about 5 inches above the tee. That’s an invitation for turbulence. As a general rule, you should provide at least 10 diameters of straight pipe upstream of any circulator. The tube leading into the circulator looks to be 3/4” so there should be at least 7.5” of pipe upstream of the flange.

Staying with Figure 1, there’s a temperature sensor held to the surface of the horizontal pipe using a single zip tie. That sensor should be secured to the pipe with at least two high temperature-rated zip ties, and then fully insulated. As mounted, this sensor will report a temperature value somewhere between the surface temperature of the pipe and the surrounding air temperature. The controller it connects to can only act on the information received from the sensor. Even with that controller perfectly installed, it’s not likely to produce the expected results.

Poorly mounted sensor = improper controller operation = noticeable problem = callback.

If you look really close at that sensor you’ll see that the “saddle” groove on the housing — which is meant to fit the curvature of the pipe — is not in contact with the pipe. It’s facing the camera. Figure 3 shows a zoomed in view.

Perhaps you think I’m getting “picky” with this detail, but why not do it the way the installation instructions show? Doing so would not cost more or increase installation time.

Finally, look at the pipe behind that temperature sensor in Figure 1. Do you see a circulator mounted with its motor shaft vertically oriented? If not, look again, it’s there. Best practice with any wet rotor circulator is to mount it with its shaft horizontal. This reduces the longitudinal loading on the bushings supporting the motor shaft.  It also helps rid the rotor can of entrapped air.

Close call

In Figure 2, you can see a larger diameter pipe that serves as a header for the circulator that’s visible, (and three other circulators you can’t see). Just to the left of the tee supplying the circulator is another temperature sensor strapped to the header with a zip tie, and very poorly insulated. Another case of poor “sensorship,” as shown in Figure 4.

The header supplying the circulator turns vertical near the left side of the photo. There you can see two tees that are “sorta close.” There looks to be at least 10 inches of pipe between the centers of those tees, which are meant to provide hydraulic separation between the boiler circulator and the header pipe. Putting the tees as close as possible is better than “sorta close.” It reduces undesirable “ghost flow” from one circuit to another.

Could it still work as installed in this system? Probably, but if you fully understand the concept underlying closely spaced tees, you’ll appreciate that putting them as close together as possible is better than sorta close.