52
Start-Up Preparation
Verify Correct Pressure Switch
1. Remove the burner hood and verify the
burner pressure switch setting.
2. Check and compare the color of the out-
line on the pressure switch label to Table
4 page 51.
The PERFORMANCE is equipped with
an air pressure switch, which provides a
safe means of shutting down the unit due
to a blockage of the combustion air inlet.
The switch is “normally closed” and
measures the change in the negative
pressure (vacuum) created by the burn-
er blower.
Verify Correct Air Shutter Setting
- Check and verify the air shutter setting
as listed in Table 5.
- The air shutter is located inside the com-
bustion air inlet adapter located in the
top /left jacket panel area. See Fig. 37.
Check Thermostat Circuit
- Unplug the Room Thermostat Snap-set
located on the rear of the unit.
- Connect a voltmeter across the end ter-
minals of the male half of the Room
Thermostat Snap-set.
- Close each thermostat, zone valve and
relay in the external circuit one zone at
a time and check the voltage reading
across the plug.
- There should NEVER be voltage mea-
sured at the plug.
- If voltage is measured at the plug under
any condition, check and correct the
external wiring.
In systems using 3-wire zone valves
backfeed of voltage to the unit is a com-
mon problem. Use an isolation relay to
prevent voltage from the external circuit
entering the Room Thermostat Snap-set.
See Fig. 33, page 46.
NOTICE
NOTICE
Table 5 : Air Shutter Settings
Fig. 37: Air Shutter Adjustment
Model Natural gas Propane
Natural gas Propane Natural gas Propane Natural gas Propane
PG-25 N/R 3.5 n/a n/a n/a n/a n/a n/a
PG-30 N/R 3.5 4.5 4.5 2.5 4.0 n/a n/a
PG-35 N/R 3.5 4.5 3.5 3.5 3.75 n/a n/a
PG-40 N/R 0 2 0 0 0 n/a n/a
PG-45 N/R 0 0 0 0 0 0 0
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