Technical Guide

251933-YTG-V-0913
10 Johnson Controls Unitary Products
NOTE: All 2 Stage Gas Heat, 60% Capacity 1
st
Stage, 40%
Capacity 2
nd
Stage.
Electric Heating Section
An electric heating section, with nickel chromium elements,
shall be provided in a range of 5 thru 30 KW, offering two
stages of capacity - 16 KW and above on 208/230 volt heaters
and 20 KW and above on 460 and 575 volt heaters. The
heating section shall have a primary limit control(s) and
automatic reset to prevent the heating element system from
operating at an excessive temperature. The heating section
assembly shall slide out of the unit for easy maintenance and
service. Units with Electric Heating shall be wired for a single
point power supply with branch circuit fusing (where required).
Unit Operating Characteristics
Unit shall be capable of starting and running at 125°F outdoor
temperature, exceeding maximum load criteria of AHRI
Standard 210/240. The compressor, with standard controls,
shall be capable of operation down to 0°F outdoor temperature.
Unit shall be provided with fan time delay to prevent cold air
delivery before heat exchanger warms up (Gas heat only).
Electrical Requirements
All unit power wiring shall enter unit cabinet at a single factory
provided location and be capable of side or bottom entry, to
minimize roof penetrations and avoid unit field modifications.
Separate side and bottom openings shall be provided for the
control wiring.
Standard Limited Warranties
• Compressor 5 Years
• Heat Exchanger 10 Years
• Electric Heat Element 5 Years
• Other Parts 1 Year
Optional Outdoor Air
Shall be made available by either/or:
• Electronic Enthalpy Automatic Economizer - Outdoor
and return air dampers that are interlocked and positioned
by a fully-modulating, spring return damper actuator. The
maximum leakage rate for the outdoor air intake dampers
shall not exceed 2% when dampers are fully closed and
operating against a pressure differential of 0.5 IWG. A unit-
mounted potentiometer shall be provided to adjust the
outdoor and return air damper assembly to take in CFM of
outdoor air to meet the minimum ventilation requirement of
the conditioned space during normal operation. During
economizer operation, a mixed-air temperature control
shall modulate the outdoor and return air damper assembly
to prevent the supply air temperature from dropping below
55°F. Changeover from compressor to economizer
operation shall be provided by an integral electronic
enthalpy control that feeds input into the basic module. The
outdoor intake opening shall be covered with a rain hood
that matches the exterior of the unit. Water eliminator/filters
shall be provided. Simultaneous economizer/compressor
operation is also possible. Dampers shall fully close on
power loss.
• Motorized Outdoor Air Dampers - Outdoor air dampers
are positioned by a 2-position, spring-return damper
actuator. The maximum leakage rate for the outdoor air
intake dampers shall not exceed 2% when dampers are
fully closed and operating against a pressure differential
of 0.5 IWG. A unit-mounted potentiometer shall be
provided to adjust the outdoor damper assembly to take in
the design CFM of outdoor air to meet the ventilation
requirements of the conditioned space during normal
operation. Whenever the indoor fan motor is energized,
the dampers open up to one of two pre-selected positions
- regardless of the outdoor air enthalpy. Dampers return to
the fully closed position when the indoor fan motor is de-
energized. Dampers shall fully close on power loss.
Other Pre-engineered Accessories Available
• Roof Curb - 14"and 8” high, full perimeter curb with wood
nailer (shipped knocked-down).
• Barometric Relief Damper - Contains a rain hood, air
inlet screen, exhaust damper and mounting hardware.
Used to relieve internal air pressure through the unit.
• Propane Conversion Kit - Contains new orifices and gas
valve parts to convert from natural to L.P. gas. One per
unit required.
• High Altitude - Natural Gas - Contains orifices required
for applications between 2000 and 6000 feet altitude.
• High Altitude - Propane Gas - Contains orifices required
for applications between 2000 and 6000 feet altitude.
Must be used with propane conversion kit.
• Low Nox - Required to reduce the emission of nitrogen
oxides below 40 nanograms per joule.
• Gas Piping - Contains 1/2” pipe nipples, fittings and gas
cock (including panel assess gaskets) required for bottom
gas supply connection with external shut off.
• Power Exhaust Option - To work in conjunction with
economizers.
• Electric Heaters
• Economizer/motorized Damper Rain Hood - Contains
all hood panels and the hardware for assembling.
• Manual Outdoor Air Damper
• Coil Guard Kit - Guard for cooling coil.
• Hail Guard
• Flue Exhaust Extension
OTHER FACTORY INSTALLED OPTIONS
• Power Exhaust Option - To work in conjunction with
economizers.
• Stainless Steel Heat Exchanger
• Stainless Steel Drain Pan
• Bottom Drain Connection