Hooded and screened openings for combustion air have been
provided in the furnace(s) access door. The air opening provides
unrestricted combustion air to the burners and sized such that
a minimum free area is maintained. The minimum free area is
defined as 1 in
2
(625 mm
2
) per 4000 BTUH (2.345 kW).
The access door provides direct access to the furnace
vestibule where the burners, combustion inducer fan, ignition
controls and ignition safeties are housed.
The vent discharge is sized such that it is equal to or larger
than the discharge area of the combustion exhaust inducer fan.
A non-adjustable High Limit Switch will shut off the gas supply
to the main burners before the outlet air reaches a temperature
exceeding 250F (121C).
The cabinet supply air flow delivery package has been
designed to provide sufficiently well distributed air flow across
the heat exchanger to limit temperature rise as follows:
• Aluminized Steel: 1030°F (575°C)
• 409 Stainless Steel: 1080°F (600°C)
• 439 Stainless Steel – 1330°F (721°C)
Clearance from combustibles to be no less than as listed below:
• Sides and back
. . . . . . . . . . . . . . . . . . . . . .
6 in (152 mm)
•
Bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 in (51 mm)
• Top
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 in (152 mm)
•
Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36 in (914 mm)
• Vent pipe to any combustible surface
. . . . .
6 in (152 mm)
Do not use this package heater if any part has been under
water. Immediately call a qualified service technician to inspect
the heater and any gas control which has been under water.
Gas Furnace Design
If the 10th digit in the model number is a “G” or “L”, the rooftop
unit was furnished with a factory installed furnace (Example,
DPS010AHCG). The Rebel commercial rooftop units are
available with either the low, medium and high heat input
). This packaged gas heat
rooftop unit is designed for outdoor non-residential installations
only. Furnace to be supplied with natural gas or LP only.
The gas heat furnace design consists of a tubular heat
exchanger, in-shot burner manifold with gas valve, induced
combustion blower, gas heat DDC control module and all
operational safeties. The tubular heat exchanger can come
with the standard aluminized steel construction or the optional
stainless steel construction. The safety switches include a
high-limit temperature switch, an auxiliary high-limit switch,
a combustion blower proof of airflow, and the flame roll-out
switch (see
Figure 48: Typical Gas Heat Section (Size 000 shown)
Gas
Gas
Field
Field
Piping
Piping
Optional Gas Heat
www.DaikinApplied.com
45
IM 1125-13 • REBEL ROOFTOPS
