York DH 300 User Manual

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262260-YTG-E-1008
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Johnson Controls Unitary Products
available for single enthalpy and differential enthalpy 
configurations, respectively).
The rainhood is painted to match the basic unit and must 
be field-assembled before installing.
POWER EXHAUST - Our economizer options are avail-
able with power exhaust. Whenever the outdoor air intake 
dampers are opened for free cooling, the exhaust fan will 
be energized to prevent the conditioned space from being 
over-pressurized during economizer operation. BAS-
ready economizer actuators have an adjustable auxiliary 
end-switch to provide a range of damper positions available 
to energize power exhaust. For units with optional VAV, 
power exhaust is energized by means of a binary output 
signal from the unit's VAV control board.
The exhaust fan, motor and controls are installed and 
wired at the factory. The rain hood must be assembled 
and installed in the field.
The power exhaust option can only be used on bot-
tom duct configurations.
MOTORIZED OUTDOOR AIR INTAKE DAMPER - 
Includes a slide-in / plug-in damper assembly with a 2-
position, spring return motor actuator which opens to a 
pre-set position whenever the supply air blower is oper-
ating and will drive fully closed when the blower unit 
shuts down.
The rain hood is painted to match the basic unit and 
must be field assembled before installing.
BAROMETRIC RELIEF DAMPER - This damper option 
can be used to relieve internal building air pressure on 
units with an economizer without power exhaust. This 
accessory includes a rain hood, a bird screen and a fully 
assembled damper. With bottom duct connections, the 
damper should be mounted over the opening in the 
return air panel. With horizontal ductwork, the accessory 
should be mounted on the return air duct.
PHENOLIC COATED EVAPORATOR AND CON-
DENSER COILS
 - Special coating process that utilizes 
Technicoat 10-1" processes. Coating is applied by total 
immersion of the complete coil for maximum protection.
ELECTRIC HEATERS wired for single point power sup-
ply. These nickel chromium heater elements are pro-
vided with limit and automatic reset capability to prevent 
operation at excessive temperatures.
VARIABLE AIR VOLUME (VAV) - A factory-installed 
variable frequency drive (VFD), mounted in the Blower 
Access compartment, is used to control the speed of the 
indoor blower motor in order to maintain a constant static 
pressure in the supply duct. A pressure transducer and 
VAV control board are mounted inside the control box. 
The drive comes completely wired and pre-programmed 
from the factory.
An optional, factory-installed manual bypass switch 
available with factory-installed VFD can be found in the 
Blower Motor Access compartment. The switch can be 
used to either route power to the VFD for modulating 
control of the blower motor, to bypass the drive and oper-
ate the motor at full speed, or to power the drive (and not 
the motor) for diagnostic purposes.
Due to space limitations, VAV is not available with any of 
the factory-installed BAS options described below, but is 
available with ‘BAS-ready’ models. Terminal blocks are 
provided in the control box for field wiring of the cus-
tomer-installed BAS.
A ‘VFD-ready’ option provides the provisions for a cus-
tomer-installed drive. The unit comes with a mounting 
bracket installed in the Blower Access compartment 
which may accommodate other vendor’s drives depend-
ing on their size. In order to utilize the unit’s mounting 
bracket, the maximum recommended drive dimensions 
are as follows:
For 5-hp motor applications ........................10” H x 6” W x 7” D
For 7.5 thru 15-hp motor applications .........13” H x 8” W x 8” D
If the drive will not fit in the allotted space, then it will 
have to be mounted elsewhere; either within the building 
on a perpendicular wall which is not subjected to exces-
sive temperature, vibration, humidity, dust, corrosive 
gas, explosive gas, etc., or within an appropriate enclo-
sure rated for outside installation to safeguard against 
moisture, dust and excessive heat.
A terminal block located in the control box is provided for 
field connection of the VFD controls.
HOT GAS BYPASS - To allow for low cooling load oper-
ation, a direct-acting pressure-modulating bypass control 
valve installed on the system #1 discharge line is used to 
divert high temperature, high pressure refrigerant around 
the TXV in order to maintain a desired minimum evapo-
rator pressure. HGBP is standard on all units with VAV 
and optional with CV units.
FILTER OPTIONS - Standard units are shipped with 2” 
throw-away filters installed. 2” pleated and 4” pleated fil-
ters are offered as a factory installed option.
CONVENIENCE OUTLET - This 110 volt outlet can be 
“powered” by the unit with a stepdown transformer or 
you may order the unit with a “non-powered” conve-
nience outlet that can be wired in the field.
DISCONNECT SWITCH - A HACR breaker sized to the 
unit max fuse size is provided. Factory installed option 
only.
BAS - Building Automation System Controls (avail-
able on two-system cooling product only).
Simplicity® INTELLI-Comfort™ CONTROL - The York® 
Simplicity® INTELLI-Comfort™ control is factory 
installed. It includes a supply air sensor, a return air sen-
sor, and an outside air sensor. There are provisions for a 
field installed dirty filter indicator switch, an air-proving