Hvac problems i have a trane commercial aircondioning unit am getting power after the fuses nothing esle works

just had my HUGE HVAC 5 ton ac fail yesterday
demand board, fuse blew 24vac, 3amps, from a surge
115F in attic fix, ouch
lucky me fill docs and schematics. and my added 24v LED demand lamp to a make fast diagnosis.
so my answer is check fuses. first. on all electrics that fail.
be the schematic from the maker and share it.

I moved you out of computer repair help, it is not.
to random TRAIN HVAC. 1.5 to 5 tons this series. (my home is 5)
FIXYA IS THE LAST PLACE ON EARTH TO ASK ABOUT HVAC.
GOOGLE TOP HVAC FORUMS, (NOT US)

Why not ask TRAIN this directly, really why not.
but high pressure is from overcharging the system.
(assumes sensors not bad)
in all cases of HVAC and Freon. variable speed compressor.too.
not cheap AC, this.
the Freon is best loaded by weight,, for sure.
a pro with lots of experience can load it by pressure and using complex charts to see correct pressure, using , ambient temp and humidity tables.
but overcharging is it. (99%)

if you were HVAC certified in USA you would not ask this question.
I'm not . learn all I know in military. (shipboard)

who installed this? call them? they did it wrong.

No power where? If you have no power how can u determine the board is bad? Need to start where power enters the machine. Then to transformer, then to board. Trane units usually have a bus fuse rather than a blade fuse.

If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

If the unit is running in cold weather than there is ice building up on the coils located outside. This is normal in that the unit is running in heat pump mode heating inside and cooling outside, After the unit detects the ice build up it briefly reverses the cycle heating the outside coils melting(defrosting) the ice which you observe as water on the pad.

The video gives you an example of the defrost cycle!
2012 Trane XL15i Heat Pump Defrost Cycle Steam Show

on older tranes if 120v power is reversed it would do that try switching leads on pigtail to board. make sure to unplug first!

13 seer minimum for new installs. I have seen ratings as high as 18 or more on
some units (410A systems)
I recently replaced my system with a 13 seer R22 system, since they are
more easily serviced and I am very familiar with them. Given the average lifespan of
a system before major service is around 10 years depending on model.
I have worked on Trane, Carrier, Intertherm and Goodman units and prefer the Goodman
units, as they seem to be much quieter running and are built in America.

If you receive an answer to this I have the exact same problem... dougakers at msn dot com

Once you have installed the jumper, you will need to kill power to the furnace for about a minute to reset the board. Make sure the the jumper is making good contact. Sometimes they appear to be plugged in but still are not making contact.

your trane heat pump energizes the reversing valve with O - orange y - is to turn on the unit make sure you have your orange wire hooked up and the tstat programming set to heatpump otherwise your reversing valve might be bad

unit could be using more power then normal if it needs cleaned, next time it blows fuse find and outlet that is still working (and not overloaded with other products) plug refrig in that outlet with extention cord and see if it blows that fuse.