Daikin F109~E109

Alarm Logic	F109 Low pressure transducer (LPT) drops lower than –90kPa within 2 seconds after the compressor starts to operate. Fuse 3 is open E109 Low pressure transducer (LPT) failure during normal operation. Fuse Fu3 is open
Possible Causes	Reduced air flow Position of Discharge gas temperature sensor (DCHS) is incorrect Low pressure transducer (LPT) cycle is faulty / Fuse Fu3 is open or cycle is failure Clogging at refrigerant cycle (SMV, EV, LSV, Drier) Low on refrigerant / Moisture in refrigerant system CPU board fault

Trouble Shooting	1. Check air flow of evaporator 1) Excessive frosting 2) Reverse rotation of evaporator fan and check the current draw	1) Activate manual defrosting 2) Check air direction by opening ventilator and check current on fan motor secondary side of magnetic contactor
	2. Check mounting position of discharge gas temperature sensor (DCHS)	2. Repair as needed
	3. Check Low pressure transducer (LPT) 1) Connect manifold gauge, compare the value of pressure gauge and LPT (refer to page 3-1). LPT value is shown on display mode sensor (refer to page 2-12)	1) If the difference in pressure is more than 30kPa, replace LPT after checking wire connection
	4-1. Liquid solenoid valve (LSV) 1) Remove the CN14 on I/O board, check resistance value of the sensor 2) LCV ON/OFF check. Listen for clicking sound of LSV body	1) The resistance value is 15.2Ω+-10% at 20 degree C 2) Replace LSV body if it does not make a sound
	4-2. Liquid line check 1) Suction modulating valve (SMV) / Expansion valve (EV) / Liquid solenoid valve (LSV) / Drier	1) Check for restrictions Replace as needed, and charge with specified amount of refrigerant
	5. Electronic expansion valve (EV) 1) Remove the CN11 on I/O board, check resistance value of coil 2) Touch EV body and check for chatter when opening (pulse) along with EV opening operation (refer to 2- 13 page) 3) Fully open the valve body using emergency magnet (refer to page 5-37) then operate the unit without mounting coil	1) The resistance value is 46Ω+-3Ω 2) Check coil or controller Coil should chatter with EV opening operation 3) If the alarm is still detected, the valve body is not working Replace EV body
	6. Low on refrigerant 1) If bubbles are present in site glass all the time and box temp is –5 degree C in frozen mode check for restriction and low on refrigerant. Recover refrigerant and charge with specified amount of refrigerant

Controller Action	F109 Unit stopped E109 Restart after 3 minutes. 9 restart attempts. Retry after 4 hours