I have a Goodman furnace (model GMH80803BNBC) (with separate Goodman AC condenser).
The specs (PDF) are located online.
The control board has stamped on it, next to the fuse (for the low-voltage (24V) portion), 5 AMP MAX.
But I cannot find in the specs, online, or elsewhere on the board what the "recommended"(not the maximum) amp rating fuse is.
Do I assume a 3 Amp fuse should be used (as that appears to be the most common rating I've come across while searching online)?
There are no additional accessories wired to / being supplied by the board besides a "regular" (not smart/wi-fi) programmable Honeywell thermostat.
A little back story:
Yesterday, one of the inside units would not run and there was no power to the t-stat.
Upon entering the attic to inspect the unit, I discovered a discarded 3 Amp fuse (which was blown) on the floor.
The 3 Amp fuse still in the control board was also blown.
I am left to assume the (discarded) fuse must have blown when the installers were testing the unit (or some point before we took ownership of the house — this is a new build house, which we've been in for about 1.5 years).
This makes me wonder, in conjunction with the 5 AMP MAX on the board, that perhaps a 5 Amp fuse should be used instead of 3 Amp?
The house has a second Goodman furnace (model GMS80603ANBE) (also with a separate Goodman AC condenser), which has a 3 Amp fuse, but the control board has nothing stamped on it about the max rating.
We've had no problems with this unit.
Best Answer
I believe that this document is for your unit and it indicates a 3amp fuse. Refer page 29, the trouble shooting section, top row, 5th column