22
Manifold Pressure Adjustment
The manifold pressure must be set to the appropriate
value for your installation. To adjust the manifold pressure:
1. Obtain the required manifold pressure setting. Refer to
either Table 6 for natural gas or Table 7 for LP/propane
gas.
NOTE:
The values listed in the tables are based
on sea level values. At higher altitudes, the heating
value of gas is lower than the sea level heating value.
2. Remove the regulator cap. Turn the high fire
adjusting screw clockwise to increase the pressure or
counterclockwise to reduce the pressure.
3. Replace the regulator cap after adjustments are
complete.
properly adjusted burner assembly, the flame bends
down and to the right at the end of the heat exchanger
tube. The end of the flame will be out of sight around
the bend.
3. After validating flame characteristics, set the thermostat
below room temperature and verify the burner flame
extinguishes completely.
Verify Over-Temperature Limit Control Operation
1. Verify the louvered control access panel is in place
and that there is power to the unit.
2. Block the return airflow to the unit by installing a close-
off plate in place of or upstream of the filter.
3. Set the thermostat above room temperature and verify
the units operating sequence (page 23).
NOTE:
The over-temperature limit control should turn off
the gas valve within approximately four minutes (exact time
depends on the efficiency of the close-off when blocking
the return air). The circulating air and combustion blowers
should continue to run when the over-temperature limit
control switch opens.
3. Remove the close-off plate immediately after the over-
temperature limit control opens. If the unit operates
for more than four minutes with no return air, set the
thermostat below room temperature, shut off power to
the unit, and replace the over-temperature limit control.
Refrigerant Charging
WARNING:
Single Package Dual Fuel iHybrid™ Heat Pumps
are shipped fully charged with R-410A refrigerant
and ready for installation. When a system is
installed according to these instructions, no
refrigerant charging is required. If repairs make it
necessary for evacuation and charging, it should
only be done by qualified, trained personnel
thoroughly familiar with this equipment. Some
local codes require licensed installation/service
personnel to service this type of equipment.
Under no circumstances should the owner
attempt to install and/or service this equipment.
Failure to comply with this warning could result
in property damage, personal injury, or death.
The system refrigerant charge can be checked and
adjusted through the service ports provided at the front
panel. Use only gauge lines which have a “Schrader”
depression device present to actuate the valve. Draw a
vacuum on gauge lines to remove air before attaching
them to the service ports on the unit. Refrigerant charging
must be done by qualified personnel familiar with safe
and environmentally responsible refrigerant handling
procedures.
Table 6. Manifold Pressure (in W.C.) for Natural Gas
Manifold Pressure (in W.C.) for
Natural Gas Installations
Altitude above
sea level
Heating Value Btu/cu. ft.
800 to 899
900 to 999 1,000 to 1,100
zero to 1,999 FT
3.5
3.5
3.5
2,000 to 4,999 FT
3.5
3.5
3.5
5,000 to 5,999 FT
3.5
3.5
3.0
6,000 to 7,999 FT
3.5
3.2
2.8
8,000 to 10,000 FT
3.0
2.8
2.5
Table 7. Manifold Pressure (in W.C.) for LP Gas
Manifold Pressure (in W.C.) and Orifice Sizes
for LP/Propane Gas Installations
Altitude above
sea level
Manifold
Pressure
Orifice
Size
zero to 1,999 FT
10.0
54
2,000 to 4,999 FT
8.5
54
5,000 to 5,999 FT
10.0
55
6,000 to 7,999 FT
9.0
55
8,000 to 10,000 FT
8.5
55
NOTE:
Manifold pressure based on sea level LP heating value
of 2,500 Btu/cu. ft.
3
Verifying Burner Operation
WARNING:
Uninsulated live components are exposed when
louvered control access panel is removed.
1. Remove the louvered control access panel and verify
there is power to the unit.
2. Set the thermostat above room temperature and
observe the ignition sequence.
NOTE:
The burner flame
should carry over immediately between all burners
without lifting off, curling, or floating. The flames should
be blue, without yellow tips. Make sure the flame is
drawn into the center of the heat exchanger tube. In
a
