- Condition: The dryer has detected a lack of air pressure in the heating chamber of the dryer.
- Alarm Action Taken: MINOR ALARM
- Component: Differential Pressure Transmitter.
- Location: Mounted inside the red control cabinet on the lower backing panel. This device is normally identified by having a clear plastic tube connected to it running back down to the lower right front corner of the cabinet connecting to a small radiator style drain valve.
Tech tip: (Reads pressure in inches of water column “IWC”) (28 IWC = 1 PSI)
(NEVER BLOW COMPRESSED AIR INTO PLASTIC TUBING INTO TRANSDUCER)
The pressure transmitter monitors the air (static) pressure in inches of water column inside the heating chamber of the dryer. It receives the air from the heat chamber through a small copper tube that connects from the drain valve in the lower right front corner of the control cabinet all the way up to inside of the heating chamber, normally only extended a few feet into the chamber.
Tools Required for Service:
- Inches of water column test gauge (if available)
- ½” open end wrench (to loosen compression nut at drain valve)
- Compressed air (to blow into the copper tube only!)
Potential Causes of this Alarm Condition:
- The dryer is not staying full exposing the top perforated screens allowing air to escape out of the top screen
- There is a blockage or crack in the tubing from the heating chamber to the transmitter resulting in low or no reading
- Low air pressure warning and/or alarm setting in controller too high
- Fan running backwards
- Belts off of fan(s)
- Blockage at moisture equalizers causing a void in grain in the column below blockage allowing air to escape from heat chamber