On the display
The panel shows LOW LIQUID TEMP FAULT. This is the only form under which the YLAA manuals print the message.
What it means
This is the unit's low chilled liquid temperature fault. The manuals print no definition beyond the message itself; their troubleshooting table links it to the leaving chilled liquid temperature cutout — a cause marked as applying to glycol only — to the micro panel's programmed setpoint/range values, to the chilled liquid flow, and to the LWT or RWT temperature sensors.
Why it appears
- The leaving chilled liquid temperature cutout is improperly adjusted — the manuals list this cause for glycol applications only.
- The micro panel setpoint/range values are improperly programmed.
- The chilled liquid flow is too low.
- The LWT or RWT sensor is defective; the manuals note that the sensor must be
properly installed in the bottom of the well with a generous amount of heat conductive compound
.
What to check
- Re-program the leaving chilled liquid temperature cutout.
- Re-adjust the setpoint/range values on the micro panel.
- Increase the chilled liquid flow; the manuals refer to the Operational Limitations in the Installation section.
- Compare the LWT or RWT sensor against a known good temperature sensing device; the manuals refer to the temperature/voltage table in the Service section. As part of this check, confirm the sensor sits in the bottom of the well with a generous amount of heat conductive compound.
Questions engineers ask
What does LOW LIQUID TEMP FAULT mean on a YORK YLAA?
It is the unit's low chilled liquid temperature fault. The manuals' troubleshooting table lists four possible causes: an improperly adjusted leaving chilled liquid temperature cutout (glycol only), improperly programmed micro panel setpoint/range values, chilled liquid flow that is too low, or a defective LWT or RWT sensor.
How do I fix LOW LIQUID TEMP FAULT on a YLAA?
Work through the manual's fixes in order: re-program the leaving chilled liquid temperature cutout, re-adjust the setpoint/range, increase the chilled liquid flow, and compare the LWT or RWT sensor against a known good temperature sensing device. The manuals do not describe a separate reset procedure for this fault.
Which sensor is involved in LOW LIQUID TEMP FAULT?
The LWT or RWT sensor. Verify that it is properly installed in the bottom of the well with a generous amount of heat conductive compound, then compare it against a known good temperature sensing device using the temperature/voltage table in the Service section.
Why is the cutout cause listed as glycol only?
The manuals mark the improperly adjusted leaving chilled liquid temperature cutout as a cause that applies to glycol applications only. The other three causes are not restricted to glycol systems.
Messages next to this one
Source
Written from the manufacturer's manuals for the YORK YLAA; every number and designation on this page is checked against them before publication. The row of the manual this message comes from:
All YORK YLAA messages: fault codes · YORK YLAA documentation · YORK manuals