What is an acceptable packing temperature range?
Finally got the truck to draft and pump to well over new spec. Adjusting the packing was an incredibly precise maneuver... too tight ... packing gets hot... too loose, lose prime. Now we have it at a point where it runs at about 106 to 112 degrees Farenheit and ambient is 75. What is an acceptable rise in temperature for the packing during operations. I am using a Raytek IR thermometer to measure. I think that this method will give us a "heads-up" on a packing or an overheating issue before it becomes serious. This would not be for running all the time, just to use during inspection schedules.
Additionally I get the 10-12 drops leaking through the packing per minute while truck is under pressure from hydrant and pump is not running, but as soon as pump starts drafting and pumping, the dripping stops. Obviously I am getting some water through the packing, or I would have a temperature issue. My thought is that maybe the volute water may be partially working it's way into the pump suction chamber instead of into the outside when a vacuum is created while drafting. Any ideas or suggestions?