Condenser keeps burning fuses
Have a 3.5 ton Rheem unit that recently started to burn fuses. Unit is five years old. It was installed by a professionally. I’m relatively handy but not very used to working on HVAC systems. System went out the first time and it took me a few hours to realize it was the fuse in the disconnect box (learned a lot about start-up capacitors though!). Swapped the fuse like for like (30 Amp time delay) and the system fired right up.
About a week (we weren’t running it much) later I noticed a dead fan again. Checked the fuse and sure enough it was dead. Swapped it again and kept a super close eye on it. When it stopped I was out within 20 minutes and when I pulled the disconnect I noticed it was also hot to the touch. I checked the disconnect box and the connections all seem good and there is not obvious signs of arcing or connection issues. I pulled the fan and checked for ground on the compressor and that was fine and ran resistance checks and that was fine.
While going through all this I finally read the sticker and found that the min fuse size is 35 amps and max is 50 amps. The current disconnect box is 30 amp rated with a 30 amp fuse. My current plan (that makes sense to me at least) is upgrading the box to a 60 amp rated box and putting in a 40 amp fuse. Current wiring is 8 gauge to a 50
Amp breaker.
What I don’t understand is why didn’t the original
Installers do this, and why did it work for a few years until now? I feel like I’m missing something.
Neighbor is coming over tomorrow with gauges to run a pressure test before I change out the box.
Anyways, just looking for any ideas from this community.
Thanks!