Ruud Furnace Code 68
Hard lockout
No blower communications. The furnace control cannot talk to the ECM blower motor at all. The furnace will not operate in any mode; if it was heating, the gas valve closes immediately.
Manual wording: “NO BLOWER COMMUNICATIONS ... The furnace control (I.F.C.) can not communicate with the blower motor.”
Documented for: (-)97V, (-)96V
Likely causes, most common first
- The wires between the blower motor have been disconnected or there is a poor connection
- There is no line voltage to the motor
- The furnace model data is faulty or corrupted
- The motor has failed catastrophically
What you can safely check yourself
- Make sure the blower door is fully closed and seated, and that the furnace switch and breaker are on.
- Power cycle once at the furnace switch.
When to call a technician
Technician job: motor wiring, line voltage to the PFC choke and ECM motor, model data card and the motor itself all have to be checked.
A Ruud furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Installation Instructions for Upflow Condensing Modulating, Communicating Gas Furnaces - (-)97V Series (92-24161-126-04) (Rheem Manufacturing Company (Ruud brand), U97V series modulating condensing gas furnace (and U98V); TABLE 18 normal operation codes, TABLE 19 fault codes, pages 94-104) · checked 2026-08-25
- Installation Instructions for 4 Position Condensing Two-Stage, Communicating Gas Furnaces - (-)96V Series (92-24161-124-08) (Rheem Manufacturing Company (Ruud brand), U96V series and (-)(-)96MDV two-stage condensing gas furnaces; TABLE 19 normal operation codes, TABLE 20 fault codes, pages 111-120) · checked 2026-08-25