246653-YTG-E-0108
92
Johnson Controls Unitary Products
to allow complete drainage. Coils in excess of 48 inches high
shall have an intermediate drain pan, also fabricated of galva-
nized powder painted steel extending the entire finned length
of the coil to provide better water drainage. Drainage from the
intermediate drain pan shall be to the primary drain pan.
OPTIONAL: Drain pans shall be constructed of stainless
steel. OPTIONAL: Evaporator coils shall be protected by the
Technicoat 10-1 four coat process. Coils shall be dipped in a
phenolic coating, which provides substantial resistance to
corrosion of aluminum and copper. OPTIONAL: Copper-tube/
Copper-finned evaporator coil assemblies.
Compressors
Units shall have two (25 ton), three (30 ton) or four (40 ton)
industrial duty hermetic scroll compressors, independently
piped and charged. Compressor frame shall be cast iron, with
cast iron fixed and orbiting scrolls. Compressors shall be
internally protected with thermal pressure relief. Each com-
pressor shall include a discharge line check valve.Compres-
sors shall be vibration isolated from the unit, and installed in
an easily accessible area of the unit.
Condenser Coils
Condenser coils shall have 3/8” seamless copper tubes,
arranged in staggered rows, mechanically expanded into alu-
minum fins. Coils shall be protected from hail damage with a
V configuration, with individual flat coils rotated 30 from the
vertical plane for each condensing circuit. Condensing coils
shall have an integral subcooler for more efficient, stable
operation. OPTIONAL: Condenser coils shall be protected by
the TechniCoat 10-1 four coat process. Coils shall be dipped
in a phenolic coating, which provides substantial resistance
to corrosion of aluminum and copper. OPTIONAL: Copper-
tube/Copper-finned condenser coil assemblies.
Condenser Fans and Motors
Condenser fans shall be direct drive, propeller type, discharg-
ing vertically. Condenser fan motors shall be 3 phase, totally
enclosed air over (TEAO) type, with built in thermal overload
protection.
Refrigerant Piping
All interconnecting piping between refrigeration components
shall be copper tubing with brazed joints. Each refrigerant cir-
cuit shall be equipped with liquid line filter drier, and moisture
indicating sight glass. Each circuit shall also have both high
and low pressure switches installed on either side of the com-
pressor and include shrader depressors for replacement of
the pressure switches without removing charge. All small
diameter distributor tubing to the evaporator coil shall be pro-
tected by polyurethane sleeves over the length of the tubing
to prevent the tubes from copper-to-copper contact during
shipment or operation.
Hot Gas Bypass (Optional on CV; standard on VAV)
Unit shall have hot gas bypass factory installed on the lead
compressor.
CONTROLS
GENERAL DESCRIPTION
Equipment with Simplicity® as standard shall be factory run-
tested through the control, after the test is complete; there will
be no wires to re-connect. All control wiring points shall be
tested and verified through communication.
The control shall be UL or CSA recognized. The control shall
be manufactured in a manufacturing facility that is certified to
ISO 9001.
COMPRESSOR CONTROL
The control shall have a five-minute Anti-Short Cycle Delay to
prevent excessive compressor cycling. The control shall
have a three-minute minimum run time to insure that oil gets
returned to the compressor each time it starts. The minimum
runtime shall be programmable up to 10 minutes.
The control shall monitor the High and Low Pressure
switches separately for each refrigeration circuit. The control
shall have a 30 second Low Pressure Switch bypass when it
starts any compressor.
A hard compressor lockout shall occur if the control detects
the same switch trip three times in a two-hour window, which
starts when the first trip occurs. On the first and second trips,
the control will turn the compressor off and wait five-minutes
after the switch re-closes, before restarting the compressor.
The control shall be capable of operating both compressors
and the economizer when there is a call for both stages of
cooling.
The control shall have a means of locking out mechanical
compression below a programmable low ambient trip point.
This must be done without adding extra components to the
unit.
The control shall have a means of locking out the mechanical
compression when the economizer is operating in free cool-
ing mode without additional components
The control shall have a means of starting the compressor
before the indoor Fan comes on w1hen operating with a
Thermostat in the AUTO FAN mode.
FAN CONTROL
The control shall have fully adjustable Fan ON and Fan OFF
delays for both Heating and Cooling settable at the control or
via communication.
The control's default Fan OFF delay for Cooling shall be 30
seconds to take advantage of the remaining capacity in the
coil after the compressor has been turned off.
