HVAC

Ruud furnace 1st heat use this year flashing error code 57. Have checked drain line and that condensation vent is filled. Any other suggestions before I replace the high pressure switch.
Thanks

Not for sure what your saying about condensation vent is filled. If you have water in the line backing up that's your problem. If not check for a restriction in the vent or combustion air pipe.

For a Ruud Ultra UGFD series gas furnace with seven segment LED diagnostics, error code 57 refers to a problem at the High Pressure Switch [HPS]. It means the Draft Inducer [DI] is working, the HPS contacts are open and as a result the Igniter is not activating, so no heat is generated. I have found that a common cause for this problem is blockage in the airway from the DI to the HPS.

The DI is connected to the HPS by a short length of rubber tubing. Each end of the tubing fits on to a nipple on each component. Remove the tubing and inspect for blockage. Also look directly into the nipple on the DI. It should be clear, but I have repeatedly seen some sort of substance blocking the nipple. I use a shopvac and a thin wire probe to draw the material out of the DI. Simple fix. Reconnect the tubing at both ends, replace the cabinet doors and restart the furnace.

Be sure to follow all safety precautions. Shut the power to the furnace off before attempting this repair.
Good luck!