Review on 📏 AR1890 Prime Professional Differential Manometer - Unbeatable Precision for Ultimate Accuracy by Christopher Clearfield

Despite a resolution of 0.01 inH2O, the reading is 0.00 for a pressure range of -0.1 to 0.1. This appears to be the same trick used on bathroom scales to fool the customer into thinking the auto-zero works. I used the following technique to measure under 0.1:1 / applied any pressure over 0.2 inches of water (e.g. x) and then pressed and released the DIF button. .2/ An outdoor reading will now show -x.3/ A desired pressure reading can be obtained by changing the outdoor reading to a resolution of 0.01 inches of water.