Daikin Maverick I, Installation And Maintenance Manual

Page: 10 / 52

IM 972-2 • MAVERICK I ROOFTOP SYSTEMS 10 www.DaikinApplied.com
Mechanical Installation
Figure 7: Suggested Gas Piping
IMPORTANT:
Disconnect the furnace and its individual shutoff
valve from the gas supply piping during any pressure testing
of that system at test pressures in excess of 1/2 pound per
square inch gauge or isolate the system from the gas supply
piping system by closing its individual manual shutoff valve
during any pressure testing of this gas supply system at
pressures equal to or less than 1/2 PSIG.
IMPORTANT: Check the rating plate to make certain the unit
is equipped to burn the type of gas supplied. Care should be
taken after installation of this equipment that the gas control
valve not be subjected to high gas supply line pressure.In
making gas connections, avoid strains as they may cause
noise and damage the controls. A backup wrench is required to
be used on the valve to avoid damage.
The capacities of gas pipe of different diameters and lengths in
cu.ft. per hr. with pressure drop of 0.3 in. and specific gravity of
0.60 (natural gas) are shown in Table 1 .
After determining the pipe length, select the pipe size which will
provide the minimum cubic feet per hour required for the gas
input rating of the furnace. By formula:
Cu. Ft. per Hr. Required = Gas Input of Furnace (BTU/Hr)
Heating Value of Gas (BTU/Ft
3
)
The gas input of the furnace is marked on the furnace
rating plate. The heating value of the gas (BTU/Ft3) may be
determined by consulting the local natural gas utility or the LP
gas supplier.
Table 1: Gas Pipe Capacity Table (Cu. Ft./Hr.)
Nominal
Iron Pipe
Size
Equivalent Length of Pipe, Feet
10 20 30 40 50 60 70 80
1/2" 132 92 73 63 56 50 46 43
3/4" 278 190 152 130 115 105 96 90
1" 520 350 285 245 215 195 180 170
1-1/4" 1,050 730 590 500 440 400 370 350
1-1/2" 1,600 1,100 890 760 670 610 560 530
Dual Voltage Inducer 208 – 230 Volt
Models
Models with gas heat feature a dual voltage draft inducer in the
furnace section. In installations where the supply voltage to the
equipment is 208 VAC, as measured using a volt meter, the
voltage tap on the furnace inducer must be changed to ensure
proper operation. This is similar to changing the tap on the
24VAC transformer.
1. Disconnect all power to the equipment.
2. Remove the control access, compressor access, and
furnace shield panels.
3. Locate the two black power wires with white connectors
going to the furnace inducer. Those will be connected to
a white wire and a black wire coming from the inducer
motor housing.
4. Disconnect the black power wire from the black inducer
wire, remove the protective cap from the red inducer
wire.
5. Connect the black power wire to the red inducer wire,
install the protective cap on the black inducer wire.
6. Reinstall the covers removed, Furnace, compressor
access, and control access.
7. Proceed to “Adjusting or Checking Furnace Input” on
page 11.
Figure 8: Factory Installed Inducer Motor Wiring
Figure 9: Recommended Field Wiring of Inducer Motor