Checked the dust monitor vacuum pump in the CS. Temperatures were all normal. Vacuum pressure was down to 16inHg. Should be around 18inHg. The air bleed valve is fully shut. Unless there is a degradation is the pump, there is a leak in the hose somewhere in the LVEA. The pump was overhauled a few months ago. At that time there was no indication of internal problems with the pump. It passed the post rebuild bench test. Next time I can get into the LVEA need to check the vacuum hose for leaks. Did not check the end stations due to COVID19 considerations Closing FAMIS #13010