What does Gardner Denver shutdown 133 open thermistor TT1 mean?
Short answer: Open circuit on temperature sensor TT1. If your Gardner Denver AirSmart controller is showing SHUTDOWN #133 OPEN THERM T1, the controller has logged a specific, documented condition. This page covers what it means, what causes it, what you can safely fix yourself, and when — and why — it takes a technician.
What exactly is the machine telling you?
The controller lost its connection to thermistor TT1 (inlet temperature on standard controllers), so it shut down rather than run blind.
Which machines show this?
Gardner Denver rotary screw compressors fitted with the first-generation AirSmart microprocessor controller — a wide range of oil-injected packages, including VFD-equipped variable-speed units where the controller supervises the drive. The first-generation AirSmart reports problems as numbered codes: SHUTDOWN #1xx and #2xx faults that stop the machine, and ADVISORY #3xx warnings that let it keep running while flagging maintenance. That numbering matters when you search — the later AirSmart G2 dropped the numbers and displays plain-text fault names instead, so a numbered code on the screen tells you that you are on the earlier controller. Shutdowns clear with Stop/Reset once the machine has stopped; advisories acknowledge with the Enter key.
What causes it?
- An intermittent connection between thermistor TT1 and the controller — sometimes a one-off
- Wiring disturbed by recent service work or vibration
- The TT1 inlet temperature sensor itself failed open
Can you fix it yourself?
One reset is worth trying — an intermittent connection can clear. If the fault persists, the sensor circuit needs proper diagnosis; the controller is right to refuse to run blind.
Step by step — what to try, in order:
- Press Stop/Reset once and see if the fault clears — it may be an intermittent connection
- Note whether the fault appeared after recent service or vibration
When do you need a technician — and why?
Proving whether the fault is the sensor or the wiring takes electrical continuity testing at the controller terminals inside the cabinet — replace-and-pray on sensors wastes money and can mask a wiring fault.
If it does come to a service call and you're in Nashville, TN or Birmingham, AL, we maintain independently compiled lists of local companies that service industrial air compressors — real businesses with verified contact information, none of whom paid to be listed.
Related questions
What does SHUTDOWN #133 OPEN THERM T1 mean on a Gardner Denver AirSmart controller?
Open circuit on temperature sensor TT1. The controller lost its connection to thermistor TT1 (inlet temperature on standard controllers), so it shut down rather than run blind.
Can I fix SHUTDOWN #133 OPEN THERM T1 on a Gardner Denver AirSmart controller myself?
One reset is worth trying — an intermittent connection can clear. If the fault persists, the sensor circuit needs proper diagnosis; the controller is right to refuse to run blind.
When does SHUTDOWN #133 OPEN THERM T1 on a Gardner Denver AirSmart controller need a technician?
Proving whether the fault is the sensor or the wiring takes electrical continuity testing at the controller terminals inside the cabinet — replace-and-pray on sensors wastes money and can mask a wiring fault. Call a technician to check the sensor wiring between TT1 and the controller if the fault persists.
Verified against service documentation: Gardner Denver AirSmart controller documentation for SHUTDOWN #133 OPEN THERM T1 (best-aire.com)