11-21-2016, 08:14 PM
The Grundfoses I've dealt with have their own tiny internal pressure tanks just to deal with slight pressure variations during off times and go on every time you turn on a faucet. They aren't designed to use external pressure tanks (but maybe other GFs are). They're also quite noisy. They also don't last too long, four or five years. I've never understood the appeal. As far as I know the only reason they've made inroads in the market here is that Waterworks became a dealer and pushed them.