Issue:
Warm starts are created by the unit's NMC. This document will explain the reason why the NMC would cause warm starts.

Product line:
All InRow products with NMC cards.

Environment:
All Serial Numbers.

Cause:
Network Issue.

Resolution:

Watchdog Features

Overview

To detect internal problems and recover from unanticipated inputs, the InRow RC air conditioner uses internal, system-wide watchdog mechanisms. When it reboots to recover from an internal problem, a System: Warmstart event is recorded in the event log.

Network interface watchdog mechanism
The InRow RC air conditioner implements internal watchdog mechanisms to protect itself from becoming inaccessible over the network. For example, if the InRow RC air conditioner does not receive any network traffic for 9.5 minutes (either direct traffic, such as SNMP, or broadcast traffic, such as an Address Resolution Protocol [ARP] request), it assumes that there is a problem with its network interface and restarts.

Resetting the network timer
To ensure that the InRow RC air conditioner does not restart if the network is quiet for 9.5 minutes, the InRow RC air conditioner attempts to contact the Default Gateway every 4.5 minutes. If the gateway is present, it responds to the InRow RC air conditioner, and that response restarts the 9.5-minute timer. If your application does not require or have a gateway, specify the IP address of a computer that is running on the network most of the time and is on the same subnet. The network traffic of that computer will reset the 9.5-minute timer frequently enough to prevent the InRow RC air conditioner from restarting.

Released for:APC Canada