Hi, I am in the process of replacing a FHP GT042 (installed in 2000) with a Waterfurnace NSV042. My original flow center (non pressurized/dual motor) seems to be working fine with the exception of some rust around motor flanges from condensation. Driller who did my ground loop advised WF contractor that due to the age of the flow center (18 years) they'd suggest replacing it too. Curious as to your opinion on that...probably another $1,5-$2k additional cost. My thought is there's not much that can fo wrong with it other than a pump or seal/gasket failure and really no reason to replace until it breaks.