The water pump fails to reach its rated output
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The rated output of the hot water circulation pump is 600 m3 with a head of 55 M; currently it can only achieve 550 m3 and a head of 32 M. Some people say it might be due to incomplete exhaust of air from the pump or pipes. Is there an exhaust valve on the pump? How is ventilation usually done?
If the exhaust is not properly managed, it should be possible for that issue to be resolved after the system has been running for some time. However, when the operating parameters do not meet the design specifications, it is not necessarily due to this reason; it could be that there are slight differences between the designed values and the actual density, pressure, and temperature of the medium, which leads to discrepancies between the design calculations and reality.
Not all water pump outlets are equipped with exhaust valves; the outlet pressure gauge can also be removed to allow exhaust
What do you think might be causing it? It has completely deviated from the performance curve; the water injection height is around ten meters, so cavitation should not occur
It’s been running for a long time yet there’s no improvement
Agree with the third floor’s opinion! The rated flow rate and head of a centrifugal pump are determined by testing it with clean water at 20 degrees Celsius under standard conditions before it leaves the factory! (At standard atmosphere, rated speed)
It must be that the wrong model was chosen! If possible, replace it with a larger impeller or increase the pump’s speed! :)
The rated output of the hot water circulation pump is 600 m3 with a head of 55 M; currently, it can only achieve 550 m3 and a head of 32 M. The key factors here are whether the pipes meet the requirements and how many bends there are in the pipes, as these all affect the flow rate and head. But this is already good enough; any manufacturer will exaggerate a bit. As for the vent valve, it must be installed in order to prevent idling.
There may be non-condensable gases inside the pump, causing a gas entrainment phenomenon. It could also be that the temperature of the liquid being transported is too high, causing vaporization inside the pump and resulting in gas formation; or it might be due to a poor seal that allows air leakage, requiring maintenance.
I think it’s possible that the gap in the mouthpiece is too large, resulting in excessive leakage; hence, the head pressure is low and the flow rate is insufficient.
If it’s not a design issue with the pump itself, then it’s an excessive pressure drop in the piping system
It seems the issue arose during the selection process; in such cases, trying to add an exhaust valve might help, as well as using as few bent pipes as possible. Is the pump’s seal not very good?
It’s probably a problem with the pump design, as the deviation is quite large. Wasn’t it inspected before leaving the factory?