On the display
The control center displays UNIT WARNING: OPTIMIZED EFFICIENCY DISABLED - CONTACT YORK REPRESENTATIVE. The manual treats it as a unit warning and a status message: it can be bypassed to view additional messages under the STATUS key by pressing the STATUS key repeatedly, which scrolls through as many as three STATUS messages that could possibly be displayed at any time.
What it means
The appearance of this message means an optimized (High IPLV) chiller is programmed for standard control. In other words, the unit is an optimized (High IPLV) machine, but High IPLV (Optimized) mode is not enabled, so the chiller is running under standard control.
Why it appears
- High IPLV (Optimized) mode is not enabled.
- The manual gives a Chiller Control Board/EPROM change or loss of factory programming as events that can leave High IPLV mode not enabled.
What to check
- Immediately contact YORK Product Technical Support or YORK ES Commercial and request the special password — Optimized IPLV cannot be enabled unless that password is entered.
- Press the SERVICE key; the panel changes to its service mode prompt and waits for the ENTER key to continue.
- Key in the 5 digit alphanumeric password provided by YORK Technical Support or YORK ES Commercial and press the √ (ENTER) key.
- Read the IPLV OPTIMIZED EFFICIENCY CONTROL screen: it indicates ENABLED when Optimized (High IPLV) is enabled and DISABLED when it is not.
- Use the ◄ and ► (ARROW) keys to enable Optimized (High IPLV) mode.
- Press the √ (ENTER) key to store the selection.
Reset and restart
There is no separate panel reset for this warning. Once the password is entered and the option is enabled using the Service Key, the message will disappear.
Until then it stays on the display as a unit warning that can be bypassed with the STATUS key to reach other STATUS messages.
Questions engineers ask
What does UNIT WARNING: OPTIMIZED EFFICIENCY DISABLED mean on a YORK YCAV?
It means an optimized (High IPLV) chiller is programmed for standard control — High IPLV (Optimized) mode is not enabled on the unit.
How do I clear the OPTIMIZED EFFICIENCY DISABLED warning?
Contact YORK Product Technical Support or YORK ES Commercial for the special 5 digit alphanumeric password, press the SERVICE key, enter the password, then enable Optimized IPLV with the ARROW keys and store with the ENTER key. The message disappears once the option is enabled.
Why did the warning appear after a control board or EPROM change?
The manual lists a Chiller Control Board/EPROM change or loss of factory programming among the events that leave High IPLV mode not enabled, which is what triggers this warning.
Can I view other messages while this warning is on the display?
Yes. Press the STATUS key repeatedly to bypass this status message and scroll through as many as three STATUS messages that could possibly be displayed at any time.
Messages next to this one
Source
Written from the manufacturer's manuals for the YORK YCAV; every number and designation on this page is checked against them before publication. The row of the manual this message comes from:
All YORK YCAV messages: fault codes · YORK YCAV documentation · YORK manuals