Diagnosing a Dryer Shutdown

The safety of your dryer is in the hands of the safety circuit. These are a series of components that are tied together. If one fails, the system will shutdown insuring the safety of your grain dryer.

Safety Circuit Overview

The contacts for incoming hot and neutral are found in the High Voltage cabinet.

The 120 volt input power to the dryer circuit for dryer controls comes from the bottom side of the transformer and runs to the top of the 8 amp mini-breaker. This breaker should be turned off and the voltage should be checked before turning the mini-breaker on. If the voltage reads anything outside of 125-volts, the supply voltage needs to be checked before powering on the mini-breaker.

Next to the mini breaker is a neutral block, which feeds all neutrals throughout the entire dryer. This neutral is connected to the neutral from the secondary side of the transformer that is standard equipment.

The incoming neutral line is connected to TB5 (white wire) and the hot line is on TB33 (after circuit breaker). The incoming 120-volt supply is an 8 amp mini-breaker.

The Safety Circuit can be viewed on page 4 and 5 of the electrical schematics. Page 4 is the Dryer Control or Fault Control portion of the Safety Circuit while page 5 of the electrical schematics contains the Dryer Safety, or Human Safety portion of the Safety Circuit. Components associated with the Dryer Control, or Fault Control portion of the Safety Circuit include the Fan Motor Overloads, High Limit Switches Linear Limits (if equipped) and Gas Pressure Switches for export model dryers. The components associated with the Dryer Safety, or Human Safety portion of the Safety Circuit are the E-Stops, Safety Relay and Plenum Door Switches for export dryers.

There are two ways to troubleshoot the Safety Circuit. One is through the Safety Circuit page of the Pinnacle 20|20 control while the other involves use of a voltmeter.

Safety Circuit Schematic

The first part of the safety circuit is the Dryer Control or Fault Control portion of the Safety Circuit. Refer to page 4 of the electrical schematics to see this portion of the safety circuit that matches exactly to your particular dryer.

The second part of the safety circuit will help diagnose a dryer shut down. This is the Dryer Safety or Human Safety portion of the Safety Circuit. See page 5 of the electrical schematics to see this portion of the safety circuit that matches exactly to your particular dryer.