I had a Radon mitigation system installed last week. When I turned on the fan it was all working great. A few days later the pressure level started to drop a little each day, until day 4 it was even. Then when I turn off the fan circuit breaker the level goes negative. So the fan is still pulling.
What would cause the pressure to be greater in the pipe, open to the outside, then in the basement?
Best Answer
You have to get rid of those bubbles, or your manometer will be completely inaccurate. A U-tube manometer works by balancing the weight and pressure on either side of the U. If there's no pressure difference, then the liquid will move until the weights are equal, which happens when the levels are the same (and, if you have the right amount of liquid, it will read "0" on the scale). If there's pressure on one side, it'll push that side down until the weight difference balances the pressure.
This all goes out the window when you have bubbles in the tube; the bubbles add height, but no weight. For example, your center picture shows the liquid tops being equal, but with that big bubble on the right it actually means that the weight on the right side is less, which means that there's more pressure on the right than on the left.
I'd get rid of the bubbles, and then check again.