Evaporator Pump Control - Daikin AGZ 025D Operating & Maintenance Manual

Enum Status
6 Off:Keypad Disable
7 Off:Remote Switch
8 Off:BAS Disable
9 Off:Unit Switch
10 Off:Test Mode
11 Auto:Wait for load
12 Auto:Evap Recirc
13 Auto:Wait for flow
14 Auto:Pumpdown
15 Auto:Max Pulldown
16 Auto:Unit Cap Limit
Auto: High Ambient Limit
17
Config Changed, Reboot
18
Required

Evaporator Pump Control

For control of the evaporator pumps, three evaporator pump control states should be used:
Off - No pump on.

Start – Pump is on, water loop is being recirculated.

Run – Pump is on, water loop has been recirculated and circuits can start if needed.
Transitions between these states are shown in the following diagram.
T1 – Off to Start
Requires any of the following

Unit state = Auto

LWT is less than the Evap Freeze set point – 0.6°C (1.1°F) and LWT sensor fault isn't active
T2 – Start to Run
Requires the following

Flow ok for time longer than evaporator recirculate time set point
24
Unit State = Off and Unit Enable Set Point = Disable
Unit State = Off and Remote Switch is open
Unit State = Off, Control Source = Network, and BAS Enable =
Unit State = Off and Unit Switch = Disable
Unit State = Off and Unit Mode = Test
Unit State = Auto, no circuits running, and LWT is less than the
Unit State = Auto and Evaporator State = Start
Unit State = Auto, Evaporator State = Start, and Flow Switch is
Unit State = Auto, max pulldown rate has been met or exceeded
Unit State = Auto, unit capacity limit has been met or exceeded
A configuration change requiring a reboot has occurred but
controller has not been rebooted yet.
POWER
ON
RUN
AGZ 025D through 190D
Conditions
false
active set point + startup delta
open
Unit State = Pumpdown
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OFF
T 2
START
T 5
OMM 1166-1