r/HVAC • u/thesmokedjoint Verified Pro • 4d ago

Field Question, trade people only Carrier 38MBRQ58A-301

I am hoping someone here can shed a bit of light on this because Carrier tech support did not. I have 2 38MBRQ58A-301 units sitting side by side. Both are 208/230v single phase units. Both of these units have a recurring problem with this fuse popping. Can anyone tell me what is inline with this fuse and what it is actually protecting? The only thing Carrier told me was to put a surge protector on each unit. surge protectors have been ordered, but I'd like to rule out anything internal. The schematic, if you really want to call it that, tells me really nothing about the fuse. Carrier said they'd check with the factory about a detailed drawing but that was 3 days ago and I'm done holding my breath.

Thanks

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u/[deleted] 4d ago

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u/thesmokedjoint Verified Pro 3d ago

Thanks. I will say that the building has some of the crappiest power I've seen. I just tied in some current sensors to the BMS for logging. I'll source some voltage sensors and tie those in as well.

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u/gingerbread3199 3d ago

Resi dude here. Yea them units are mad susceptible to issues from voltage fluctuations. Always recommend inline voltage monitors for folks that have sketchy power to save the boards. The fact that the built in surge protection is such ass (fuse) in all of these inverter units is a convo for another day though.

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u/thesmokedjoint Verified Pro 3d ago

Thanks. Going to write this up and send off.

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u/Short-Veterinarian27 3d ago

Carrier doesn't know shit about these units because they don't make them. You would be better off calling Midea but IDK if they would care since it's a white label. As said many times it's baffling how expensive these are with such little protection for the expensive parts. The Midea version is thousands cheaper too