Fujitsu takes a shocking licking and keeps on ticking

[JKopp]

Computer rm down - no cool air

Never got the straight answer on who done this but someone took the 208 volt power wires and moved them to number 1 & 2 communication terminals as the color of the wires matched up would be my guess. I looked at this roof top unit and went what the f***.

So as I turn off power and move the power wires to where they belong L1 & L2 I send power to the proper terminals and she is not working. Not to surprised at this point. I pull the lid off and dig into the electronics. Well look at this a blown 5 amp fuse. So now I am digging through the truck and find a 5 amp automotive fuse on a bad CB pulled off a furnace earlier in the day. Put the spade connectors on the 5 amp automotive fuse and she works. Unbelievable if you ask me... What other product can you do this too and not let the factory smoke out.

Crappy install if you ask me as power was tapped off a 40 amp 3pole disconnect for a package unit 10' away. Illegal for a commercial building not to have 208 volt wire in a conduit. We bid on this install and now I see why we did not get it.

The only factory thing I see is Fujitsu needs to work on their label integrity as this unit is not that old. I think a couple of years, 410A refrigerant and all.

[gravity]

sooooooo......this thing ran like that for how long?

[R Mannino]

WOW!

Good to know.

[craig1]

Unbelievable if you ask me... What other product can you do this too and not let the factory smoke out.

I once wired 480V to the 24V side on a carrier rooftop unit. blew the 24V fuse, blew the 25A 480V fuse, no other damage.

Its hard to explain how this happened, but for those familiar with Carrier RTUs it has to do with the 24V limit switch in the blower motor.

[JKopp]

sooooooo......this thing ran like that for how long?

I can't imagine it worked wired this way. I think we had a Sparky wannabe messing with it. I never looked it over before this trouble call.

[ryan1088]

That's pretty funny considering it is well labeled. Durrrr. Hard to believe it didn't tear something up.

[craig1]

I can't imagine it worked wired this way.

actaully it probably did run that way. take a look at the wires. the white wire is just a jumper. the black wire is also just a jumper, but it goes through the fuse. The red wire is the communication wire, and that one looks ok.

the difference between hooking it up this way and the right way is that the indoor unit now has no fuse protection and the outdoor unit gets its power through that tiny fuse. The outdoor units are so efficient that I suppose its possible that it ran fine for years through that fuse

[chuckcrj]

Yes, it worked fine that way.

Like Craig stated, the 5 amp fuse was protecting the outdoor unit instead of the indoor unit, this is the only difference.

[JKopp]

He did have that pussled look when i said someone changed this wiring. Wow, ok then that may make sense as we had some long heat waves roll through the hottest in like 4 years and the fuse finally gave up. Hard to believe the outdoor unit was running on that little 5 amp. Thanks for the insight.

[VanIsleRefrig]

last fujitsu i went and worked on had a TCA of 3.8a, it was a 24k btu with 2 heads both on heat to 88f so it was ramped right up. crazy how efficient they are.