Cause : 24 V supply low comes when the 24 V DC is measured on the control card. This alarm arises when the detected voltage of terminal 12 is lower than 18 V.

• Check for a defective control card. WARNING 48, 1.8 V supply low
• The 1.8 V DC supply used on the control card is outside of allowable limits.
• The power supply is measured on the control card.
• Check for a defective control card.
• If an option card is present, check for an overvoltage condition.