troubleshooting pumps

bovide_3

How do you tell if a circ. pump is working effectively? I guess the only way is to install a flow meter on the line?

Mark Eatherton1

Not necessairily...

With non wet rotor pumps, you can check the amperage. The higher the amp draw, the more GPM it's moving. Unfortunately, the manufacturers have not caught on to this potential troubleshooting tool, so you are on your own.

On wet rotor pups, they draw the same amperage with a locked rotor as they do with a full load, so the amp draw test won't work here.

With all pumps, if you put a tap on the line before and after the pump, then install one LARGE face, small range pressure gauge between the two taps, you will be able to see how many PSI the pump is generating. You convert PSI to feet of head by multilpying the PSI times 2.307. You can then take the manufacturers performance curve and find the feet of head, and then determine the current GPM. For ease of installation you can use ice maker tap saddle valves and 1/4" copper tubing. When you're done, close the taps and pull the gauge set fo ryour next application. The gauge will read the total net pressure differential. It saves you from havng to do the math.

Remember, if its a multi zone valve system with one pump, the flow rate changes dependent upon how many zones are calling.

Another quick check method for wet rotor pumps is to take a torch and hold it on the pipe while the pump is running. Keep it there for 10 or 20 seconds. If you see no change in pipe color, theres a good chance that water is moving through the pipe, thereby cooling it. Wait 5 seconds, then CAREFULLY touch the spot on the pipe where you had heated it up. If its cool, there is flow. Doesn't tell you how much flow there is, only that there is flow.

The last way you could determine that there was flow in the pipe would be to use a flow meter or circuit setter.

ME