Welcome! Here are the website rules, as well as some tips for using this forum.

# Understanding the Taco 007e

Member Posts: 1
edited August 2020

Assuming this is correct, how does the pump sense the increased demand?

• Member Posts: 22,877
Not a calculus problem at all -- just the way pumps operate. First, step back and look at the basic 007 (without the e). This is a bog standard centrifugal pump, and is notable for (and useful because of!) a remarkably flat pump characteristic at constant speed (60 hz). Now what Taco has done is swap out the older AC motor (which will run until Doomsday, but at only one speed) for a variable speed, electronically controlled motor (hence ECM).

The pump's controls sense the flow or pressure difference, and vary the speed of the motor to reach the desired flow (there are other conditions which can be sensed, such as delta P or delta T). The 8.8 gpm at 10 feet of head is the maximum the pump with the original motor can reach. Below that head, the old pump's flow was greater; above that head, less -- the difference is that the 007e's electronics give a constant head (in normal mode) at any flow up to 8.8 gallons per minute.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
• Member Posts: 21,793
I think 1 gpm in a 250' loop of 1/2 pex @120F would be around 8' head?
1 gpm seems a bit high, the RadPad shows a suggested max. of .6 gpm in a 300' loop of 1/2".
Unless the 1 gpm is just for an example?

This journal take you through the steps of developing a system curve, overlay on the pump curve.
Also how the various delta p functions work.

https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_16_na_0.pdf
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 703
Hi there
you're right, the 007, and 007e are fundamentally variable flow, net flow is dictated by the system resistance. first step in sizing the pump, is knowing the amount of BTU's that have to get delivered to load. Next the piping has to be sized adequately to accommodate the flow rate required based on Load. quick rule of thumb for a 20 degree delta T, is approximately 1 GPM per 10,000 BTUs. the resistance through the selected length of pipe and diameter will give you the two variables necessary (Flow & Head), to size a pump. Here's where your analysis compares, the flow rate through 250 lineal feet of 1/2" pipe is the pressure drop the pump is pumping against and dictates where the pump operates on it's curve. This is true with both types as Jamie Hall so eloquently explains in this tread. There's a great video on tacocomfort.com called understanding ECM circulators. For your convenience, I provided a link.
http://www.tacocomfort.com/products/variable_speed_products/007e/index.html
great way to understand why electronically commputated motors, ECM are more efficient, in comparison to PSC type AC motors.
Please reach out to Taco Tech support at 401-942-8000 is you have additional questions regarding any Taco products.
Joe Mattiello
N. E. Regional Manger, Commercial Products
Taco Comfort Solutions
• Member Posts: 3,537
This weeks Taco After Dark covers this topic