Filter
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5. Base Rail
a. Unit shall have base rails on a minimum of 2 sides.
b. Holes shall be provided in the base rails for rigging shackles to facilitate maneuvering and overhead rigging.
c. Holes shall be provided in the base rail for moving the rooftop by fork truck.
d. Base rail shall be a minimum of 16 gauge thickness.
6. Condensate pan and connections:
a. Shall be a sloped condensate drain pan made of a non--corrosive material.
b. Shall comply with ASHRAE Standard 62.
c. Shall use a 3/4” --14 NPT drain connection, possible either through the bottom or side of the drain pan. Con-
nection shall be made per manufacturer’s recommendations.
7. Top panel:
a. Shall be a single piece top panel on 04 thru 12 sizes, two piece on 14 size.
8. Gas Connections:
a. All gas piping connecting to unit gas valve shall enter the unit cabinet at a single location on side of unit (ho-
rizontal plane).
b. Thru--the--base capability
(1.) Standard unit shall have a thru--the--base gas--line location using a raised, embossed portion of the unit
basepan.
(2.) Optional, factory approved, water--tight connection method must be used for thru--the--base gas connec-
tions.
(3.) No basepan penetration, other than those authorized by the manufacturer, is permitted.
9. Electrical Connections
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
basepan.
(2.) Optional, factory approved, water--tight connection method must be used for thru--the--base electrical con-
nections.
(3.) No basepan penetration, other than those authorized by the manufacturer, is permitted.
10. Component access panels (standard)
a. Cabinet panels shall be easily removable for servicing.
b. Unit shall have one factory installed, tool--less, removable, filter access panel.
c. Panels covering control box, indoor fan, indoor fan motor, gas components (where applicable), and com-
pressors shall have 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 compos-
ite 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 al-
lowed.
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 rollout switch or 4 con-
tinuous 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.
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