Why did my Quincy compressor shut down on high temperature?
Short answer: High discharge temperature shutdown. If your Quincy QSI series (QSI standard controls) is showing HIGH TEMP, 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 discharge temperature exceeded the programmed shutdown temperature, so the controller stopped the compressor to prevent airend and lubricant damage.
Which machines show this?
Quincy QSI industrial rotary screw compressors with the standard QSI control panel — larger plant-air packages, some fitted with Quincy's integrated refrigerated dryer, whose faults (DRYER CONT., DRYER D.P.) appear on the same display without stopping the compressor. The QSI panel reports faults as short text messages — OVERLOAD, HIGH TEMP, SUMP HAT, TEMP FAULT — rather than numeric codes, so search the exact wording on your display. "Sump" in these messages means the fluid separator vessel, and "fluid" is Quincy's term for the compressor lubricant. Faults clear from the panel after the cause is corrected; the manual keeps the electrical enclosure strictly off-limits to unqualified hands.
What causes it?
- Cooler faces buried in dust and debris
- Hot or unventilated compressor room
- Fluid level low, or fluid filter/separator overdue for a change
- Failed thermal valve or clogged internal cooler when it repeats
Can you fix it yourself?
Usually — ventilation, clean coolers, and correct fluid level clear most high-temperature shutdowns. A repeat after those fixes means internal cooling parts are failing.
Step by step — what to try, in order:
- Improve compressor-room ventilation and check the ambient temperature
- With the unit stopped and powered off, clean dust and debris off the cooler faces
- After the unit has fully cooled and depressurized, check the fluid level and top up if low
- Check whether the fluid filter or separator is overdue for a change
- Allow the unit to cool, reset, and restart
When do you need a technician — and why?
Thermal valve replacement and internal cooler cleaning mean opening the hot, pressurized fluid system — the manual warns never to crack a fitting until the unit is stopped, cooled, and fully depressurized.
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 HIGH TEMP mean on a Quincy QSI series (QSI standard controls)?
High discharge temperature shutdown. The discharge temperature exceeded the programmed shutdown temperature, so the controller stopped the compressor to prevent airend and lubricant damage.
Can I fix HIGH TEMP on a Quincy QSI series (QSI standard controls) myself?
Usually — ventilation, clean coolers, and correct fluid level clear most high-temperature shutdowns. A repeat after those fixes means internal cooling parts are failing.
When does HIGH TEMP on a Quincy QSI series (QSI standard controls) need a technician?
Thermal valve replacement and internal cooler cleaning mean opening the hot, pressurized fluid system — the manual warns never to crack a fitting until the unit is stopped, cooled, and fully depressurized. Call for service if the shutdown repeats after cleaning coolers and correcting fluid level — a failed thermal valve or clogged internal cooler needs a technician.
Verified against service documentation: Quincy QSI series (QSI standard controls) documentation for HIGH TEMP (manualslib.com)