Pelpro PPC90 Service Manual page 37

FIREBOX VACUUM & VACUUM SWITCH TROUBLESHOOTING
1. Install a vacuum "TEE" between the vacuum switch and
drop tube.
2. Install the vacuum gauge to the "TEE".
3. Turn thermostat on or dial control. ***NOTE: make
sure fuel is in the hopper as this can effect the vacuum
reading. It takes a minimum of .04 inches of water
column to close the vacuum switch.****
4. Your vacuum gauge should be reading between .19 to
.30 inches of water column while the exhaust blower is
running on HIGH. (on a cold appliance & NO Fire).
ALL VACUUM READINGS ARE MEASURED IN INCHES
OF WATER COLUMN. LONG VERTICAL VENT RUNS
WILL PRODUCE GREATER VACUUM COMPARED TO
HORIZONTAL RUNS.
Low vacuum can be the result of a leaking door gasket,
firepot not closing all of the way, dirty heat exchanger, or
plugged vent system.
Always make sure the appliance is clean before making
any repairs.
37
NOTE:
VACUUM "TEE" VACUUM "TEE"
GREEN
VACUUM SWITCH VACUUM SWITCH
8390-017A
(VACUUM GAUGE)
RED = LOW VACUUM
= OPERATING RANGE
BLUE = SHUTDOWN
06/21