Factory tested as complete pumping packages
Volume 2/ Issue 4/ July 2015
These six words, in the specs for every Bell & Gossett Domestic® Pump Series, add up to one word: confidence. Our production team assembles each unit and conducts multiple performance tests, linking the results to the unit’s factory serial number file.
Units ordered with control panels are tested through that control panel. We inspect appearance, check float switches and test seals and gaskets for leaks. Pump performance is typically tested at four condition points along the pump curve. For condensate return and boiler feed units, those points are:
- Dead head or no flow, which measures the maximum discharge pressure for the unit.
- The actual gpm at the RATED discharge pressure.
- The actual discharge pressure at the RATED flow.
- Maximum flow.
In a perfect world, points 2 and 3 would be the same, but in reality, they seldom are. Impellers in our pumps are trimmed to the nearest 1/16th inch increment for your specified capacity. The real flow when generating the rated discharge pressure may actually be a gallon or two higher per minute. Similarly, the real discharge pressure at the rated flow may be one or two psi higher. So while those points are very close on the pump curve, they are different.
Maximum flow is subjective. We fully open the fixture’s valves and let the pump run out the end of the curve, to just before the starting point for cavitation. Or we run the pump motor into the service factor area, to the point where the pump is drawing almost full load SFA (service factor amps), typically around 110 percent. That keeps us inside the overload protection range so we don’t pop fuses or circuit breakers or thermal overload relays. All ODP and TEFC motors in our Domestic Pump Series have a minimum 1.15 service factor. At each point of testing, we record amps draws for the motor.
Vacuum heating units go through similar tests to insure that discharges are correct when the pump is pumping from a vacuum, that air can be removed and that the vacuum can be maintained at appropriate levels. Testing also lets us set those levels on the diaphragm vacuum switch that controls the vacuum pumps.
For the customer, this all adds up to confidence. It means products leaving our factory have gone through extensive testing and are proven to work as advertised. Testing can also provide comparative information for troubleshooting units and isolating problems on troublesome installations.
Here’s what the factory recently gave to a customer who asked to see our test data.