I got the ammeter assembled today. My Intex SF70110 pump/filter pulls 4.2 A @117 V. with the filter pressure about "middle ways" between "just backwashed" and "needs backwashed now". The manual and motor tag say 4.8 A. The pump pulls 3.8 A deadheaded.

Just for grins, I checked a cheapo heat gun that's rated at 1500 W 120 V. That converts to 12.5 A. It actually pulled 10.8 A 117 V. or about 1250 W. Heating devices are routinely rated at higher than actual wattage to make them "seem" more powerful. So - - - I feel like the meter is reasonably accurate.