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48VGUK: Installation Instructions
4. Verify the following conditions:
a. Make sure gas line is free of air. Before lighting the unit for the
first time, perform the following with the gas valve in the OFF
position:
NOTE: If the gas supply pipe was not purged before connecting the
unit, it will be full of air. It is recommended that the ground joint union
be loosened, and the supply line be allowed to purge until the odor of gas
is detected. Never purge gas lines into a combustion chamber.
Immediately upon detection of gas odor, retighten the union. Allow 5
minutes to elapse, then light unit.
b. Make sure that outdoor-fan blade is correctly positioned in the
fan orifice.
c. Make sure that air filter(s) is in place.
d. Make sure that condensate drain trap is filled with water to
ensure proper drainage.
e. Make sure that all tools and miscellaneous loose parts have been
removed.
Start-up
WARNING
!
FIRE, INJURY, OR DEATH HAZARD
Failure to follow this warning could result in property damage, personal
injury, or death.
Do not bypass any of the safety controls in the unit, including but not
limited to the main limit switch, rollout or burner rollout switch, and
pressure switch/pressure transducer.
Step 1 – Check for Refrigerant Leaks
WARNING
!
EXPLOSION HAZARD
Failure to follow this warning could result in
death, serious personal injury, and/or property
damage.
Never use air or gases containing oxygen for leak
testing or operating refrigerant compressors.
Pressurized mixtures of air or gases containing
oxygen can lead to an explosion.
Proceed as follows to locate and repair a refrigerant leak and to charge
the unit:
1. Locate leak and make sure that refrigerant system pressure has been
relieved and reclaimed from both high- and low-pressure ports.
2. Repair leak following accepted practices.
NOTE: Install a filter drier whenever the system has been opened for
repair.
3. Add a small charge of Puron (R-410A) refrigerant vapor to system
and leak-test unit.
4. Recover refrigerant from refrigerant system and evacuate to 500
microns if no additional leaks are found.
5. Charge unit with Puron (R-410A) refrigerant, using an accurate
scale. Refer to unit rating plate for required charge.
Step 2 – Start-up Heating and Make Adjustments
Complete the required procedures given in the Pre-Start-Up section
before starting the unit. Do not jumper any safety devices when
operating the unit. Make sure that burner orifices are properly aligned.
Unstable operation my occur when the burner orifices in the manifold
are misaligned.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Follow the lighting instructions on the heating section operation label
(located on the inside of the control access panel) to start the heating
section.
NOTE: Make sure that gas supply has been purged, and that all gas
piping has been checked for leaks.
Fig. 11 – Burner Assembly
Fig. 12 – Monoport Burner
Check Heating Control
Start and check the unit for proper heating control operation as follows
(see furnace lighting instructions located on the inside of the control
access panel):
For 208/230 VAC Models:
Start and check the unit for proper heating control operation as follows
(see furnace lighting instructions located on the inside of the control
access panel):
1. Place room thermostat SYSTEM switch in the HEAT position and
the fan switch is placed in AUTO position.
2. Set the heating temperature control of the thermostat above room
temperature.
3. On a call for heating, the inducer motor will start up for a 30 second
pre-purge.
4. The control will then check to see the pressure switch closed. Then
the main burner should light within 5 sec. of the spark being
energized. If the burners do not light, there is a 22-sec. delay before
another 5-sec. try. If the burners still do not light, this sequence is
repeated. If the burners do not light on the 4th ignition attempt,
there is a lockout. To reset the control, break the 24-v power to W.
NOTE: The ULN system will sound different from a traditional furnace
that utilizes inshot burners. For the ULN system, the access door is part
of the system and must be installed on the unit for any sound
evaluations.
15
A180078
A200293
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