User's Manual

1068152-YTG-L-0815
Johnson Controls Unitary Products 181
a. All unit power wiring shall enter unit cabinet at a single, factory- prepared, knockout location. b. Thru- the-
base capability.
(1.) Standard unit shall have a thru- the- base electrical location (s) using a raised, embossed portion of the
unit base-pan.
(2.) Optional, factory- approved, water- tight connection method must be used for thru- the- base electrical
connections.
(3.) No base-pan penetration, other than those authorized by the manufacturer, is permitted.
9. Component access panels (standard)
a. Cabinet panels shall be easily removable for servicing.
b. Unit shall have one factory installed, toolless, removable, filter access panel.
c. Panels covering control box, indoor fan, indoor fan motor, gas components (where applicable), and
compressors shall have a molded composite handles.
d. Handles shall be UV modified, composite. They shall be permanently attached, and recessed into the
panel.
e. Screws on the vertical portion of all removable access panel shall engage into heat resistant, molded
com
posite collars.
f. Collars shall be removable and easily replaceable using manufacturer recommended parts.
23 81 19.13.I. Gas Heat
1. General
a. Heat exchanger shall be an induced draft design. Positive pressure heat exchanger designs shall not be
allowed.
b. Shall incorporate a direct- spark ignition system and redundant main gas valve.
c. Gas supply pressure at the inlet to the rooftop unit gas valve must match that required by the manufacturer.
2. The heat exchanger shall be controlled by an integrated gas controller (IGC) microprocessor.
a. IGC board shall notify users of fault using an LED (light- emitting diode).
b. The LED shall be visible without removing the control box access panel.
c. IGC board shall contain algorithms that modify evaporator- fan operation to prevent future cycling on high
temperature limit switch.
d. Unit shall be equipped with anti- cycle protection with one short cycle on unit flame roll-out switch or 4
continuous short cycles on the high temperature limit switch. Fault indication shall be made using an LED.
3. Standard Heat Exchanger construction
a. Heat exchanger shall be of the tubular- section type constructed of a minimum of 20- gauge steel coated
with a nominal 1.2 mil aluminum- silicone alloy for corrosion resistance.
b. Burners shall be of the in- shot type constructed of aluminum- coated steel.
c. Burners shall incorporate orifices for rated heat output up to 2000 ft (610m) elevation. Additional accessory
kits may be required for applications above 2000 ft (610m) elevation, depending on local gas supply
conditions.
d. Each heat exchanger tube shall contain multiple dimples for increased heating effectiveness.
4. Optional Stainless Steel Heat Exchanger construction a. Use energy saving, direct- spark ignition system. b.
Use a redundant main gas valve.
c. Burners shall be of the in- shot type constructed of aluminum- coated steel.
d. All gas piping shall enter the unit cabinet at a single location on side of unit (horizontal plane).
e. The optional stainless steel heat exchanger shall be of the tubular- section type, constructed of a minimum
of 20- gauge type 409 stainless steel.
f. Type 409 stainless steel shall be used in heat exchanger tubes and vestibule plate
g. Complete stainless steel heat exchanger allows for greater application flexibility.
1. Optional Low NO
x
Heat Exchanger construction
48HC