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Otis hydro-fit stuck in MTH

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(@Philelevman)
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We have an Otis hydrofit stuck on MTH. We have replaced the I-O board and the Processor board repeatedly with no luck. The MTH sensor is fine. We have unplugged it and jumped it out with no change. Any suggestions? Thanks in advance

Last edited by Philelevman; 09/12/24 07:21 PM. Reason: More info


   
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(@TheElevatorGuy)
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I am guessing that MTH = Motor Thermal related. Often a fault like that may latch itself and require a manual reset sequence to put the car back in service, rather than silently resetting once the thermal condition clears (in which case a mechanic might never realize it’s happening over-and-over again). Possibly this is done via the service tool/OFT?



   
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(@Philelevman)
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Topic starter  
We have reset it over and over and over and cleared the ram as well with no success. I don't know if there's a special reset for the MTH but nothing seems to eliminate the MTH



   
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(@TNHapa84)
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Motor Thermal Overload

Pre-ANSI 2010 code:
Motor thermal overload contact (MTH) connects to 10-422 on P22-1. Reference MOTION
CONTROL (125 VAC): MOTOR OVERLOAD, STARTER CONTROL AND RUN BOX and
VALVE CONTROL AND OIL PRESSURE MONITORING sections of the wiring diagram. The
normally close thermal contact switch opens at 72C (160F). Lifting the wire from the MTH
input (PMO) will simulate a motor thermal overload. The car will not run; motor will not start.
MCSS status will show SHD and the MCSS event log will show error code of either 2616 or
2617 to indicate contact is open. Replace wire on 10-422 on P22-1 and confirm voltage to
return the car to service. No controller reset should be necessary.

ANSI 2010 code:
Motor thermal overload contact (MTH) connects to 10-417 on P23-3. MOTION CONTROL
(125 VAC): STARTER CONTROL & OIL LEVEL MONITORING. The normally close thermal
contact switch opens at 72C (160F). Lifting the wire from the MTH input (PMO) to 10-417
(P23-3) will simulate a motor thermal overload. The car stops, moves to the bottom landing,
opens and closes the doors, and then performs a shutdown operation. The door open button
remains operational. No retries are allowed.

Once the car shuts down, the MCSS status will show SHD and the MCSS event log will show
error code 2645. To clear the shutdown, replace wire on 10-417 on P23-3 and confirm
voltage; you must clear RAM (M-1-5-1 and M-2-4) and then reset the GCS CPU (M-2-2-3) to
return the car to service. Clear the MCSS event log (M-2-2-1-1, then blue key + 5 (sel out)) to remove logged error code.



   
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