AC Blown Fuses - How to test them and why they blow

How to test AC Blown Fuses and why they blow? We show how a low voltage fuse works to protect the low voltage circuit in am air conditioner. How to use a volt and ohm meter to test and how to inspect the system for the cause.
Check out our 208V vs 240V video here: • How is 208 volts diffe...
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[@kennyjohnson4411]

Awesome video!

[@randallshawver3]

Never worked on HVAC before, but through this video, I was able to diagnose and fix the issue. 3 wires were so old they had Roman numerals on them. Replaced them and done! Thanks!

[@b-2466]

I'm about to finish my second semester of school for hvac. This channel helps so much.

[@loganguzman6856]

Awesome video best I seen! Congratulations and thank you for helping us out!

[@TeslaBoy123]

Thanks for sharing this 👍

[@nhattuygiaithiensaunguyen9885]

Thank you so much your video help me learned a lot

[@joejesko7410]

Shorted wires are probably the most common, but I had a system recently that was blowing fuses because the contactor was bad. Very low resistance (ohms), so basically it was shorting out. Easy fix once problem was diagnosed.

[@austrianpainterhidingfromt5920]

I'm learning the tech side after having been an installer, and that just happened to me last week. I opened up the air handler to find a pile of blown fuses laying in there, apparently is was a chronic issue. When I put a new fuse in, the relay in the AHU made this strange clicking sound, I thought maybe the relay was bad, replaced it, same thing. I ended up checking the contactor on the condenser and it read only .2 ohms, replaced that and everything started up fine.
I don't know why the AHU relay was clicking but my guess is that sporadic low voltage from that contactor beginning to short was clicking it on and off.

[@baitcasterdisaster8981]

I’ve ran into a low voltage fuse that was blowing intermittently and it was quite humbling. I had 2 call backs before I ended up pulling a new wire to the outdoor unit and I haven’t been back since. Each time I visually inspected everything and isolated all low voltage circuits but couldn’t find it so I put a new fuse in and when I left it was working. Then a few days later I’d get a call back it was very frustrating

[@arielhernandez2911]

This is great man

[@nakiapringley5391]

Awesome video 💯💯💯💯💯

[@paisaconstructiondavid1964]

Muchas gracias, if I understood correctly an E fuse is 3.5 amp?

[@ncooty]

@3:05: No need to remove the fuse to check continuity. Just touch the probes to the top contacts.

[@michaelcostello6991]

Is low voltage usually AC and not DC ? Do we come across DC often. Thanks for great video

[@turbo12v]

Hi
I have a new heat pump installed 2 yrs ago (Carrier)
I didn’t pay attention until this past winter season in FL,that my unit doesn’t turn outside on heat mode,just the heating strip in the air handler unit.
It’s a heat pump ! I look at the reversing valve on condenser to make sure they install the correct unit.
But it won’t reverse anything at all! I think it’s the thermostat,but I would like to get a second opinion to see what else besides the thermostat I can start looking at. Thanks

[@repeatman]

I would check and see if the reversing valve wire is hooked up. If it's not on some units it won't reverse the flow of refrigerant.

[@jmac213stuff]

What the proper amp/volt rating for 120 and 208/240 v systems? Are they all rated for 24v?

[@geekedbot5784]

Why would the transformer blow before the fuse ? One of the outdoor fan wires came out & I put it back in place. Once I turned the unit on the transformer was done. Why ?

[@jandshatton331]

I just saw this. The last tech didn't put the capacitor back in the clamp and left it dangling. Eventually it made contact with the wall and shorted the fuse out

[@migosmadeira9892]

I have a 35 yr old Bryant air handler , there’s no circuit board and I can’t find a 3 amp fuse. What happend was I bypass the thermosthat with a paperclip, in the proccess , I think I shorted something the AC won’t run. If I can’t find a fuse , any suggestions which part is shorted? The AC was working before I did the bypass.

[@jeffreylamelas8102]

Yes please call your local HVAC company

[@jasonkinney8129]

Call a tech.

[@josephfarrow2685]

Those old air handlers did not have fuses. You probably shorted the transformer

[@texasterry4414]

Did you use a plastic paper clip? That’s crucial...and definitely a red one.

[@monteglover4133]

Be extremely careful when testing voltages to ground you can often get improper voltage readings

[@chuckdearruda6271]

👍🏽

[@andresperez-wc8ty]

Shorted coils are a source of shorts, i always check

[@donnierobertson3088]

Ok

[@pathannold6150]

Heat blowing cold o

[@danmartens1282]

Can a thermostat with batteries installed and c wire connected cause fuse to blow.?

[@texasterry4414]

No

[@samboherring3673]

Just put a bigger one in

[@teamaztecas763]

To confusing. You should keep it simple

[@nakiapringley5391]

Awesome video 💯💯💯💯💯💯