R717Kid
18-07-2010, 08:20 PM
What if any, would the detriments be to having a hermetic ammonia pump grossly oversized? My thinking is that one that is too far oversized would cause turbulence in the vessel as the excess ammonia is bypassed through the minimum flow orifice. The pump was oversized with the expectation that additional cooler space would be added soon after the last expansion. However, that has not happened. The pumps had always made noise and the discharge valve has always had to be throttled down to stop the noise (taking into account all other possibilities to eliminate cavitation).
Secondly, along with the above issue, the bypass and motor recirculation piping goes against manufacturer recommendations. So much so that the pump manual has the warning on page 1 in bold black letters "do not pipe the pump bypass and motor recirculation into a common header". However, both pumps bypass and motor recirculation piping goes into a common header (without check valves) which then dumps into the wet suction return from the evaporators. I found this causes flow through the standby pump and cavitates the pump in service.
The standby pump is now isolated, but hoping for insight on the rest. Thanks,
Secondly, along with the above issue, the bypass and motor recirculation piping goes against manufacturer recommendations. So much so that the pump manual has the warning on page 1 in bold black letters "do not pipe the pump bypass and motor recirculation into a common header". However, both pumps bypass and motor recirculation piping goes into a common header (without check valves) which then dumps into the wet suction return from the evaporators. I found this causes flow through the standby pump and cavitates the pump in service.
The standby pump is now isolated, but hoping for insight on the rest. Thanks,