Daikin UATYQ25ABAY1, Operation Manual

Original instructions

Installation manual

17

We reserve the right to make changes without any prior notice.

UATYQ*Y1

Packaged Rooftop

4P522681-1A

CODE

DESCRIPTION

MAIN CAUSES

CHECKS AND TROUBLESHOOTING RESET UNIT 

OFF

ITEMS OFF

AL13

Compressor 2 

maintenance

It has been exceeded 

Compressor 2 operating 

hours threshold.

Check the compressor working 

conditions.

M (1)

No

None

AL14

Unit Maintenance

It has been exceeded unit 

operating hours threshold.

Unit check up. Perform the ordinary 

maintenance operations.

M (1)

No

None

AL15

Main fan overload/

interblock

Thermal protection ventilation 

fan

Check working conditions.

M

Yes

All

Check fans motor cabling, terminals and 

adsorbed current.

Check thermal overload switch.

AL16

Filter dirty

The pressure drop across 

the filter measured by the 

differential pressure switch is 

higher than the set value

Clean or replace the air filters.

M

No

None

Calibration of the differential pressure 

switch for clogged filters.

M

AL17

Not used

-

-

-

-

-

AL18

Flow-switch alarm

The differential air pressure 

switch detects a pressure 

(airflow) lower than the set 

point

Check working conditions (airflow and 

pressure).

M

Yes

All

Check working operation of the 

ventilation fans.

Check air distribution system.

Check the correct intervention of the 

airflow switch.

AL19

Clock broken or 

not present

The clock board is defective

Reboot the controller; if alarm persists, 

replace the main board.

M

No

None, hourly 

programming not 

operating

AL20

Summer setpoint 

< winter setpoint

Summer set point is lower 

than winter set point or 

winter set point is higher 

than summer set point and 

automatic changeover is 

enabled

Check for the correct temperature set 

point (cooling and heating modes).

A

Yes

All

AL21

B1 probe broken or 

disconnected

The reading of the probe B1 

(supply airflow differential 

pressure probe) exceeds the 

operative range

Check working conditions.

M

No

All components 

and fuctions 

directly related to 

the probe

Check in the controller for the correct 

probe reading range .

Check the correct reading of the probe 

and eventually replace it.

Check probe wiring and terminals.

Check correct functioning of the 

analogic input of the main board.

AL22

B2 probe broken or 

disconnected

The reading of the probe B2 

(return airflow differential 

pressure probe) exceeds the 

operative range

Check working conditions.

M

No

All components 

and fuctions 

directly related to 

the probe

Check in the controller for the correct 

probe reading range .

Check the correct reading of the probe 

and eventually replace it.

Check probe wiring and terminals.

Check correct functioning of the 

analogic input of the main board.

AL23

B6 probe broken or 

disconnected

The reading of the probe B6 

(condensing pressure circuit 

2) exceeds the range

Check working conditions.

M

No

All components 

and fuctions 

directly related to 

the probe

Check in the controller for the correct 

probe reading range .

Check the correct reading of the probe 

and eventually replace it.

Check probe wiring and terminals.

Check correct functioning of the 

analogic input of the main board.