Bought into the pre-infusion hype on my cheap machine and it backfired hard

So I watched like 4 YouTube videos about modding a Gaggia Classic to do pre-infusion manually. Spent $12 on a dimmer switch from Amazon and wired it up. First 3 shots? Amazing. Then on day 4 my pump started making this horrible whine noise and now it barely pushes water through. Pretty sure I fried something. Shoulda just left it alone and focused on my puck prep instead. Anyone else kill a pump trying to add features a $300 machine just doesn't have?

2 comments

2 Comments

wesley_grant333h ago

Blame the machine not your wiring job all you want but you skipped the part where you should've verified the dimmer was rated for your pump's load.

uma3062h ago

And that's a fair point up to a point, Wesley, but here's the thing. A lot of these newer variable speed pumps have a startup surge that can be way higher than the running load, so even a correctly rated dimmer might get zapped on that first spin up. The manual for my Grundfos pump actually says right in bold letters not to use any standard dimmer at all, to use their specific controller module instead. So it's not always just a matter of matching the numbers on the box. Sometimes the manufacturer has already done the homework for you and the answer is "none of these.