Daikin McQuay IM 934-5, Installation & Maintenance Data

Page: 28 / 48

Page 28 of 48 IM 934-5
Unit Protective Logic
Compressor Minimum Run Time
For thermostat-controlled running cycles, the compressor
will have a minimum run time of 90 seconds. The compres-
sor can be stopped at any time if the system is switched to
any Mode, except the Cool Dry Mode.
Compressor Minimum Off Time (delay on break)
When compressor is under the thermostat control, it has a
3-minute delay before restarting when it has cycled off.
Indoor Coil Freeze Protection
In Anti-Freeze Mode, the compressor and outdoor fan will
be stopped and the display will show “CF”. The compressor
and outdoor fan can be started only if the following condi-
tions are met:
1. after the 3 minute delay on break, AND
2. the indoor coil reaches 49°F or above and remains there
for at least 1 minute, OR
3. another Mode is selected.
The system is in Anti-Freeze Mode when the following
conditions are met:
1. The control is in either Cool or Cool/Dry Mode.
2. The indoor coil reaches 32°F and stays there for at least
five (5) minutes.
3. The compressor has run for at least 90 seconds.Sleep
Timer is overridden during this operation.Anti-freeze
Protection is active in all modes of operation and when
the control is Off.
Room Freeze Protection
When room temperature falls below 41°F, the electric heater
is controlled, or the hydronic valve is opened and the indoor
fan operates on High Speed. The compressor and outdoor
fan are off and the display will show “rF”. The electric
heater is controlled, or hydronic valve will close when the
room temperature rises back to 50°F. During room freeze
conditions, the temperature setting can be adjusted with the
touchpad. Fan modes and Sleep Operation are overridden
during Room Freeze Protection. Room Freeze Protection is
active in all modes of operation and when control is off.
Temperature Limiting
When the room temperature drops 5°F below minimum
set point, the display will indicate “Lo.” When the room
temperature rises 5°F above maximum set point, the display
will indicate “hI.” Alarm indications of 5°F above or below
set point will be consistent with the set up mode settings for
minimum and maximum temperatures.
Temperature Limit Settings
1 To adjust the lower operating temperature limit (cool
minimum set point) press and hold Fan Mode button
and adjust the setting with Up or Down buttons. The
minimum setting is 60ºF (15ºC).
2. To adjust the upper operating temperature limit (heat
maximum set point) press and hold down Fan Speed
button and adjust the setting with Up and Down buttons.
The maximum setting is 85ºF (30ºC). When control
selection is set for “T'STAT,” the maximum setting can
go up to 90ºF (32ºC).
3. The upper operating temperature limit will be displayed
first.
4. Default settings are: Cool minimum 60ºF (15ºC) and
Heat maximum 85ºF (30ºC).
Electrical Service Considerations
All wiring should be done in accordance with all local and
National Electrical Code requirements. The conditioners are
supplied as follows:
Electric Heat Unit
1. 208V and 230V models are supplied with a power
cord which will exit from beneath the conditioner on
the control side. The cord has a usable length of 72"
(457.2mm) from where it exits the conditioner. The use
of an extension cord is not recommended. Time delay
fuses are recommended to avoid nuisance tripping. The
receptacle is generally mounted beneath the conditioner
on or recessed in the wall so that it is concealed by the
conditioner over hang. The space under the conditioner
must be at least 3" (76mm) high.
2. An electrical subbase is available for 208V and 230V
units and contains a junction box for a field-mounted
receptacle All electrical connections are made within the
subbase, thus eliminating the need for a wall mounted
receptacle.
The subbase is available in 3" (76mm) or 4" (102mm)
height and can be furnished with factory-mounted fused
disconnect option.
3. On all 265V models, an electrical subbase is required.
The chassis is supplied with a “short cord” which is
just long enough to plug into the subbase. A plug cord
cover is also furnished with the subbase to make the
interconnecting cord inaccessible as required by the
National Electrical Code. The conditioner is marked with
the minimum circuit ampacity and maximum fuse size.