PG80VTLA: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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* Orifice numbers 43 are factory installed
Check Safety Controls
The flame sensor, gas valve, and pressure switch were all checked in the
Start-up procedure section as part of normal operation. 
1. Check Main Limit Switch 
This  control  shuts  off  combustion  system  and  energizes
air-circulating  blower  motor,  if  furnace  overheats.  By  using  this
method  to  check  limit  control,  it  can  be  established  that  limit  is
functioning  properly  and  will  operate  if  there  is  a  restricted
return-air supply or motor failure. If limit control does not function
during this test, cause must be determined and corrected.
a. Run furnace for at least 5 minutes.
b. Gradually block off return air with a piece of cardboard or sheet 
metal until the limit trips.
c. Unblock return air to permit normal circulation.
d.  Burners will re-light when furnace cools down.
2. Check  draft  safeguard  switch.  The  purpose  of  this  control  is  to
cause the safe shutdown of the furnace during certain blocked vent
conditions. 
a. Verify vent pipe is cool to the touch.
b. Disconnect power to furnace and remove vent connector from 
furnace vent elbow.
c. Restore power to furnace and set room thermostat above room 
temperature.
d. After normal start-up, allow furnace to operate for 2 minutes, 
then block vent elbow in furnace 80 percent of vent area with a 
piece of flat sheet metal.
e. Furnace should cycle off within 2 minutes. If gas does not shut 
off within 2 minutes, determine reason draft safeguard switch did 
not function properly and correct condition.
f. Remove blockage from furnace vent elbow.
g. Switch will auto-reset when it cools.
h. Re-install vent connector.
NOTE:  Should  switch  remain  open  longer  than  3  minutes,  furnace
control  board  will  lockout  the  furnace  for  3  hours.  To  reset  furnace
control board, turn thermostat below room temperature or from HEAT to
OFF and turn 115-v power OFF, then back ON.
3. Check Pressure Switch(es) 
This control proves operation of the draft inducer blower. 
a. Turn off 115-v power to furnace.
b. Disconnect inducer motor lead wires from wire harness.
c. Turn on 115-v power to furnace.
d. Set thermostat to “call for heat” and wait 1 minute. When 
pressure switch is functioning properly, hot surface igniter 
should NOT glow and control diagnostic light flashes a status 
code 32. If hot surface igniter glows when inducer motor is 
disconnected, shut down furnace immediately.
e. Determine reason pressure switch did not function properly and 
correct condition.
f. Turn off 115-v power to furnace.
g. Reconnect inducer motor wires, replace outer door, and turn on 
115-v power.
h. Blower will run for 90 seconds before beginning the call for heat 
again.
i. Furnace should ignite normally. 
Checklist
1. Put away tools and instruments. Clean up debris.
2. Verify  that  switches  SW1-1  and  SW1-6  are  OFF  and  other  setup
switches are set as desired. Verify that switches SW1-7 and SW1-8
for the blower OFF DELAY are set as desired per Table 10.
3. Verify that blower and burner access doors are properly installed.
4. Cycle test furnace with room thermostat.
5. Check operation of accessories per manufacturer’s instructions.
6. Review User’s Guide with owner.
7. Attach literature packet to furnace. 
ALTITUDE RANGE
FT. (M)
AVG. GAS HEAT 
VALUE AT 
ALTITUDE 
(BTUH/CU FT.) 
SPECIFIC GRAVITY OF NATURAL GAS 
0.58  0.60  0.62  0.64 
Orifice No. 
Manifold 
Pressure
High/Low 
Manifold 
Pressure
High/Low  
Orifice No. 
Orifice No. 
Manifold 
Pressure
High/Low 
Orifice No. 
Manifold 
Pressure
High/Low  
USA
7001 to 
8000 (2134 
to 2438) 
650  44  3.6/1.6  43  3.2/1.4  43  3.4/1.5  43  3.5/1.5 
675  44  3.3/1.5  44  3.5/1.5  44  3.6/1.6  43  3.2/1.4 
700  45  3.8/1.6  44  3.2/1.4  44  3.3/1.4  44  3.4/1.5 
725  46  3.7/1.6  46  3.8/1.7  45  3.7/1.6  44  3.2/1.4 
750  46  3.4/1.5  46  3.6/1.5  46  3.7/1.6  46  3.8/1.6 
775  47  3.6/1.6  47  3.8/1.6  46  3.4/1.5  46  3.6/1.5 
800  47  3.4/1.5  47  3.5/1.5  47  3.7/1.6  47  3.8/1.6 
825  48  3.7/1.6  48  3.8/1.6  47  3.4/1.5  47  3.6/1.5 
USA
8001 to 
9000
(2438 to 
2743) 
625  44  3.3/1.5  44  3.5/1.5  44  3.6/1.6  43  3.2/1.4 
650  45  3.7/1.6  44  3.2/1.4  44  3.3/1.4  44  3.4/1.5 
675  46  3.6/1.6  46  3.8/1.6  45  3.7/1.6  45  3.8/1.7 
700  47  3.8/1.7  46  3.5/1.5  46  3.6/1.6  46  3.7/1.6 
725  47  3.6/1.6  47  3.7/1.6  47  3.8/1.7  46  3.5/1.5 
750  48  3.8/1.7  47  3.5/1.5  47  3.6/1.6  47  3.7/1.6 
775  48  3.6/1.5  48  3.7/1.6  48  3.8/1.7  47  3.5/1.5 
USA
9001 to 
10,000
2743 to 
3048) 
600  45  3.7/1.6  45  3.8/1.7  44  3.3/1.4  44  3.4/1.5 
625  46  3.6/1.6  46  3.7/1.6  46  3.8/1.7  45  3.8/1.6 
650  47  3.8/1.6  46  3.4/1.5  46  3.6/1.5  46  3.7/1.6 
675  47  3.5/1.5  47  3.6/1.6  47  3.7/1.6  46  3.4/1.5 
700  48  3.7/1.6  48  3.8/1.7  47  3.5/1.5  47  3.6/1.6 
725  48  3.5/1.5  48  3.6/1.6  48  3.7/1.6  48  3.8/1.7 
Table 12 – Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate (Tabulated Data Based on 22,000 Btuh High-Heat/14,500 Btuh 
for Low-Heat per Burner, Derated 4 Percent for Each 1000 Ft.(305 M) Above Sea Level) (Continued)