Daikin McQuay IM 934-5, Installation & Maintenance Data

Page: 25 / 48

IM 934-5 Page 25 of 48
Control Lockout Feature
The control is placed in a lockout mode of operation when
Mode button is held pressed for 10 seconds. Display will
show “LC” to confirm Lockout Mode has been entered.
Once in this Lockout Mode the control board will not take
any commands at all. In Lockout, unit will continue to
operate with the same settings just prior to Lockout Mode.
This means the touchpad will no longer be able to pass
commands to the control. User’s set point will normally be
displayed. Any button pushed will bring “LC” on display for
five seconds.
To exit the Lockout Mode and return to normal (regular)
mode of operation, press the Mode button for 10 seconds.
Display will show “nL” for five seconds to confirm normal
mode has been resumed.
Sequence of Operation
Cool Mode
In Cool Mode, the compressor will start if the temperature
at the space temperature sensor is 1°F or higher than the set
point. It will stop if the space temperature sensor is 2°F or
lower than the set point, subject to timing requirements.
In the Cool Mode, the indoor fan will operate according to
the user settings for Fan Mode – Continuous or Cycle and
Speed.
Cold Start
Cold start is initiated when the control has not called for
cooling for more than two (2) hours or during a power-
on-reset.
During cold start, the set point is lowered by 4°F
(Tset-4°F) if the differential calls for cooling. The unit will
operate in cold start until the new set point is satisfied (+
or – 1°F) or until the unit has run in cold start for at least 20
minutes. After one or both conditions are met, the set point
will be reset to the user setting and the unit will run in the
regular cool mode.
The indoor fan will operate according to the user settings for
mode – Continuous or Cycle and Speed.
Cold start is not available with the
Sleep feature.
Sleep Function
Sleep time is adjustable by the user from 1 to 15 hours in
one (1) hour increments in a closed loop. The sleep time is
adjusted and set via the touchpad and by pressing the Sleep
Button repeatedly. On the touchpad, the display will show
the set time in numbers for five (5) seconds. Before the sleep
time expires, the setting can be adjusted above the number of
hours passed by pressing the Sleep Button. Pressing the On/
Off Button can terminate the Sleep Mode.
A changeover from Heat to Cool or another Mode will reset
the Sleep Timer.
The Sleep Function will be deactivated by pressing the
power-on-reset or any button (except sleep) on the touchpad
or the Remote Control.
Cool Dry Mode
Select the Cool Dry Mode when the standard Cool Mode
does not provide sufficient dehumidification. In Cool Dry
Mode, the unit must run in Cool Mode for 12 minutes or
until the temperature differential between the room tempera-
ture and the set point is less than 2°F. This will also occur
after a Cold Start or a Mode change from Cool to Cool Dry.
During this time the fan will operate in the Mode and Speed
selected.
Until one or both of the above conditions are met, the con-
trol will determine which Dry Mode (Zone) is initiated based
on the temperature differential between the room tempera-
ture (Tr) and the temperature set point (Ts):
Note:
Cool Dry is not available with Sleep Function.
Figure 32: If Tr - Ts > 4°F, operation will be in Zone A
Compressor
L
ow Fan
12 mins
.
On
Off
On
Off
*
t
t
*
= Zone Determination Time
Figure 33: If 2°F < Tr - Ts < 4°F, operation will be in Zone
B
Compressor
L
ow Fan
t
On
Off
On
Off
30 secs
.
30 secs
.
8
mins
.
4 mins
.
t