Safety Features - Rheem 801T Series Installation Instructions Manual

LIMIT CONTROL/HALC
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 .
There are several reasons for a limit switch to open and almost
always involve low airflow through the furnace .
1 . A dirty or restricted air filter .
2 . A dirty or restricted cooling coil .
3 . Undersized or restricted return air system .
4 . Undersized or restricted supply air system .
5 . A problem affecting the main blower:
A . A wrong speed tap selection .
B . Failing motor bearings .
C . Low voltage to the motor .
D . Dirty blower wheel .
E . Wrong motor rotation .
F . Blower wheel slipping on the
F . motor shaft .
6 . Overfiring the furnace with too much gas pressure .
7 . Ventilation problems .
8 . Failed blower motor .
FLAME ROLL-OUT SAFETY SWITCHES
Furnaces are equipped with safety switches to protect against
flame roll-out conditions in the burner compartment, which,
if tripped, will terminate the heating cycle . In the event of a
flame roll-out condition, the switch will shut the furnace down .
Switches for the furnaces are located on either side of the
burner cover plate . 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 trip-
ping . If this unit is mounted in a closet, the door must be closed
when making this check .

SAFETY FEATURES

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 .
There are several reasons for the pressure switch not to close .
1 . An inoperative induced draft blower .
2 . A loose or leaky pressure switch hose .
3 . A blockage in the vent .
4 . Severe downdrafts canceling the draft from the inducer fan .
5 . A leaky gasket at the induced draft blower .
6 . Improperly sized or installed vent .
The pressure switch contacts must open before the unit can go
through another heating cycle .
See diagnostic chart in this book for diagnostic recommenda-
tions .
WARNING
!
DO NOT BYPASS, JUMPER, OR REMOVE ANY SAFETY
SWITCH FROM THE FURNACE CONTROL CIRCUIT . IF
A SAFETY SWITCH CAUSES THE FURNACE TO SHUT
DOWN OR OPERATE INTERMITTENTLY, IT IS AN INDI-
CATION OF A POTENTIAL SAFETY HAZARD THAT MUST
BE ADDRESSED BY A QUALIFIED TECHNICIAN, SER-
VICE AGENCY OR THE GAS SUPPLIER . DO NOT RESET
SAFETY CONTROLS WITHOUT CORRECTIVE ACTION
AND/OR VERIFICATION OF PROPER SAFE OPERATION
BY A QUALIFIED INSTALLER, SERVICE AGENCY OR
THE GAS SUPPLIER .
REPLACE ANY SAFETY CONTROL COMPONENT ONLY
WITH IDENTICAL OEM REPLACEMENT PARTS . WHEN
A NEW SAFETY SWITCH IS INSTALLED, IT MUST BE
TESTED FOR A MINIMUM OF 15 MINUTES WITH THE
FURNACE OPERATING AT MAXIMUM INPUT RATE AND
WITH BOTH BLOWER AND BURNER DOOR INSTALLED .
IF THE FURNACE IS INSTALLED IN A CLOSET, THE
CLOSET DOOR MUST ALSO BE CLOSED FOR THIS
TEST . REPEAT THE TEST AT THE MINIMUM INPUT
RATE IF THE FURNACE IS A MULTI-STAGE FURNACE .
47