FieldBench
Goodman codes

Goodman

b2

Lockout

HP mismatch vs shared data

Connected motor horsepower does not match the value in the furnace shared-data set. Furnace will not operate.

Walk b2 in Diagnose

4 plates — walk the one on the cabinet

First check

1 Read the plug / card on THIS cabinet

On Goodman GMVC80 the model plug or shared-data card must match this cabinet size. A 100 kBtu plug in an 80 cabinet overfires and limits. A leftover memory card after a control swap throws d0/d4-class codes. Wrong replacement motor for this cabinet size.

Expect: Plug / card part matches the rating plate and the replacement control bulletin.

The rest of the walkthrough is Diagnose.

On the plates

  • Compare motor HP stamp to the furnace model and the shared-data card.
  • After an IFC or motor swap, the card from the old board must travel with the cabinet size.
  • A ¾ HP motor in a 1 HP cabinet (or the reverse) throws b2 even when the wheel spins.
  • Motor HP stamp vs this GMVM97 size and the card on the IFC.
  • A GMVC96 two-stage motor/card mix throws b2/d4 even when the wheel would spin.
  • Wrong replacement motor for this cabinet size.
  • Wrong memory card after an IFC swap (see d0/d4).
  • Do not ‘make it work’ with a different HP ECM — ComfortBridge CFM tables are card-specific.

Plates that use b2

Same number, other makers

b2 on Goodman is not the same code on these plates.