The house I recently bought has a radon mitigation system that was installed 20 yrs ago. The system has 2 3inch pipes thru the slab, one in the middle of the basement and one next to a side wall about 12 ft. from the pretty well sealed sump pit. From what I can gather from the previous owner the system does not use perforated pipes under the slab, just spaces dug out at the slab penetrations. The basement has a french drain which appears to have been sealed with an epoxy type material. I have a U-tube type manometer and it reads 1.5 wc (out of 4). House is a 33 yr. old ranch with a mostly finished basement. My home inspection last May included a test which resulted in a level of 2.1 pCi/L in the basement. Once we moved in I purchased an electronic radon detector which basically matched the canister test done by the inspector, readings floated around 1.5 to 2.5 in the basement. Once it got cold in Nov. and the windows were closed the readings in the basement went up to around 5.5 pc/l. I moved the detector upstairs to a bedroom and I'm seeing around 3.0 pCi/L. I think this I high for upstairs. My questions/concerns are:

1. Assuming the fan is 20 yrs old, can it be tired and just not working so good anymore?

2. The fan is a discontinued fantech R150. I found drop-in replacements by RadonAway, they have a more *****ful unit, model RP265, can a stronger fan help out?

3. The basement flooded about 5 yrs ago, could a flood event compromise the system by possibly filling in the dug out spaces under the slab penetrations?

Thanks in advance for any feedback. Drew W.