Have a shutdown OTIS 211 hydro in a Hotel. I'm not with OTIS and have no information on the job site. Here's what I do have:
1. Main Board LED window displays "STLU"
2. Flashing red leds on "RING" and "HRT" on main board.

Any help would be appreciated.

stall in the up direction (stlu)

The unit is sitting just below the bottom landing, is it possible that this unit tripped the low oil timer and is sitting on the bottom limit preventing just a re-set to bring it back on line. this would make sense since there is a college football team staying at this hotel right now....

is the fault on all the time? i would kick the lift(safely) above the bottom floor then reset the lift to see if it clears the fault.

There were some adjustment issues on a string of Maxton valves where the unit would go into viscosity control and the elevator would creep up real slow generating the stlu fault. If I remember correctly decreasing the bypass pressure corrected this.

a "VALV" fault would indicate the valve problem. It happeneds when the car bypasses the oil to heat it up to temp during olt operation and the car moves out of the door zone because the valve is not adjusted properly. Like you said , i usually crack the bypass open half a turn and check it again to see if it clears the problem , rather than turn off the oil temp function.

On that last post, if you add oil additive for a tight packing it will change the viscosity of the oil. If bypassed is not set correctly you will get a "valv" fault, the car will creep up through viscosity mode. As to your "stlu" fault check your upper limit switches there always on the edge, I think its The L4s sw.