Checking Auxiliary Limit Control; Control - Intertek ACVC96 Service Instructions Manual

SERVICING
VOLT / OHM
METER
Testing Primary Limit Control
(90% Furnaces)
4. After completing check and/or replacement of primary
limit control, reinstall burner compartment door.
5. Turn on electrical power and verify proper unit operation.
To aid in identifying these controls, refer to the Primary Limit
Charts in furnace Technical Manual for part number, tem-
perature setting and color(s) code.
S-301 CHECKING AUXILIARY LIMIT CONTROL
The auxiliary limit control is designed to prevent furnace op-
eration in case of main blower failure in horizontal or coun-
terflow installations. It may also open if the power supply is
interrupted while the furnace is firing.
The auxiliary limit control is suitable for both horizontal right
and horizontal left installations. Regardless of airflow direc-
tion, it does not need to be relocated. The (2) two auxiliary
limits are located on the blower housing (one on each side),
as shown in the following illustration.
AUXILIARY LIMIT

CONTROL

BLOWER HOUSING
Auxiliary Limit Control Location
(Select 90% / 95% Furnaces)
Manual or Automatic Reset Auxiliary Limits Located
in Blower Side
1. Remove the wires from the auxiliary limit control termi-
2. Using an ohmmeter, test for continuity across the two
COLOR
IDENTIFYING
TAB
S-302 CHECKING FLAME ROLLOUT CONTROL
A temperature activated manual reset control is mounted to
the manifold assembly on 90% furnaces, as shown in the
following illustration.
AUXILIARY LIMIT
CONTROL
WARNING
HIGH VOLTAGE
D ALL
ISCONNECT POWER BEFORE SERVICING OR
M
INSTALLING THIS UNIT. ULTIPLE POWER SOURCES MAY
F
BE PRESENT. AILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
nals.
terminals (only test when the auxiliary limit is at room
temperature).
VOLT / OHM
METER
Testing Auxiliary Limit Control
T
O AVOID POSSIBLE FIRE, ONLY RESET THE AUXILIARY LIMIT CONTROL
I
ONCE. F IT SHOULD OPEN A SECOND TIME, A QUALIFIED SERVICER
MUST DETERMINE WHY THE AUXILIARY LIMIT OPENED BEFORE
RESETTING AGAIN.
RED
RESET
BUTTON
COLOR
IDENTIFYING
TAB
WARNING
67