Safety Features; Limit Control; Pressure Switch - Rheem GPH series Installation Instructions Manual

FIGURE 24
DOWNFLOW BLOWER REMOVAL

SAFETY FEATURES

LIMIT CONTROL

The high limit cut-off temperature is set
at the factory and cannot be adjusted.
The temperature setting prevents the
air temperature leaving the furnace
from exceeding the maximum outlet air
temperature, which, if exceeded, will
shut the furnace down. Some reasons
which could cause the outlet
temperature to exceed the range
include: failed indoor blower, dirty
filters, etc.
OVER TEMPERATURE
SAFETY SWITCHES
Furnaces are equipped with safety
switches to protect against
overtemperature conditions in the
burner compartment, which, if tripped,
will terminate the heating cycle. In the
event of an overtemperature condition,
the switch will shut the furnace down.
The switch for the dedicated UPFLOW
FURNACE and DOWNFLOW is
located just above the burners on the
blower divider panel. Switches for the
UPFLOW/ HORIZONTAL FURNACES
are located on either side of the burner
brackets and just above the burners on
the blower divider panel. If a switch is
tripped, it must be manually reset. DO
NOT jumper or reset this switch. If this
switch should trip, a qualified installer,
service agency or the gas supplier
should be called to diagnose and/or
correct the source of tripping. If this
unit is mounted in a closet, the door
must be closed when making this
check.
LUBRICATION
The indoor blower motor and induced
draft motor are prelubricated by the
motor manufacturer and do not require
further attention.
The motors must be cleaned
periodically by a qualified installer,
service agency, or the gas supplier to
prevent the possibility of overheating
due to an accumulation of dust and dirt
on the windings or on the motor
exterior. Air filters should be kept
clean. Dirty filters can restrict airflow
and results in motor overheating.
Reference Figure 24 for proper
removal of the blower assembly on
downflow models.

PRESSURE SWITCH

This furnace is equipped with a
normally-open pressure switch that
monitors pressure conditions within the
furnace vent system during the heating
cycle.
Replace only with a switch with
identical settings. Replacement of the
pressure switch is not required at high
altitudes.
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