Furnace runs but some rooms are too hot while others are too cold.

Safety first: Turn off power before adjusting blower speed on the control board.

Steps:

• Ensure all supply registers and returns are open; avoid closing too many registers, which can affect furnace operation.
• Replace the air filter.
• Partially close registers in overheated rooms to push more air to colder rooms, but do not close more than 20–30% of total registers.
• A technician can adjust blower speed taps or ECM profiles on the CTC control board and evaluate duct design for better balance.