On the display
The panel reads UNIT WARNING: INVALID SERIAL NUMBER ENTER UNIT SERIAL NUMBER. The manual prints this exact wording as the only variant of the message, and it is listed among the unit warnings for the YVAA control center.
What it means
The appearance of this message may mean the chiller has lost important factory-programmed information: the serial number and other important data may need to be reprogrammed. The fault table for this model gives the cause as invalid or lost serial number data. Because factory-programmed information may be involved, the manual directs that Johnson Controls Product Technical Support be contacted immediately when the message appears.
Why it appears
- Invalid or lost serial number data.
- Loss of important factory-programmed information — the message may indicate this, in which case the serial number and other important data may need to be reprogrammed.
What to check
- Contact Johnson Controls Product Technical Support at once:
Immediately contact Johnson Controls Product Technical Support.
- Set the date and time on the chiller before any programming.
Changing the programming of this feature requires the date and time to be set on the chiller before programming.
- Enter the serial number using the SERVICE key; programming requires the factory-provided password. The manual outlines further details in its Serial Number Programming section.
- If other messages must be read while the warning is up, press the STATUS key repeatedly to bypass this status message — as many as three STATUS messages could possibly be displayed at any time.
Reset and restart
No automatic reset or restart sequence is described for this warning. The recovery the manual gives is reprogramming: with the date and time set on the chiller, the serial number is entered using the SERVICE key with the factory-provided password, after Johnson Controls Product Technical Support has been contacted. Bypassing the message with the STATUS key only serves to view additional messages; the manual does not describe it as a way of clearing the warning.
Questions engineers ask
What does UNIT WARNING: INVALID SERIAL NUMBER ENTER UNIT SERIAL NUMBER mean on a YORK YVAA?
The manual says the message may mean the chiller has lost important factory-programmed information, and that the serial number and other important data may need to be reprogrammed. The cause given is invalid or lost serial number data.
How do I enter the serial number on a YORK YVAA chiller?
Set the date and time on the chiller first, then enter the serial number using the SERVICE key; the factory-provided password is required. The manual's Serial Number Programming section has additional information, and Johnson Controls Product Technical Support should be contacted immediately.
Can I see other messages while this warning is displayed?
Yes — press the STATUS key repeatedly to bypass this status message and scroll through the other messages; as many as three STATUS messages could possibly be displayed at any time.
Do I need a password to program the serial number?
Yes. Programming the serial number requires the factory-provided password, and the date and time must be set on the chiller before programming.
Messages next to this one
The same message on other models
Source
Written from the manufacturer's manuals for the YORK YVAA; every number and designation on this page is checked against them before publication. The row of the manual this message comes from:
All YORK YVAA messages: fault codes · YORK YVAA documentation · YORK manuals