Testing Auxiliary Limit; Checking Flame Rollout Switch - Daikin APGM3 Service And Troubleshooting

SERVICING
High Voltage!
Disconnect all power before servicing or
installing. Multiple power sources may be
present. Failure to do so may cause property
damage, personal injury or death.
1. Remove electrical power to unit. Some units may
have more than one source of power.
2. Remove the wires from the limit control terminals.
3. Using an ohmmeter, test for continuity across the two
terminals.
4. If limit test open allow unit to cool and retest.
5. If still open, replace the control.

Testing Auxiliary Limit

The auxiliary limit control is a preset nonadjustable control
mounted in the blower compartment area.
It is connected in series with the rollout switch wiring to the
gas valve. If its temperature should be exceeded, it will
open, interrupting the voltage to the gas valve causing it to
open.
An additional limit (primary limit) control is required for
safety control of high temperature within the furnace or
ductwork.
AUX. LIMIT
High Voltage!
Disconnect all power before servicing or
installing. Multiple power sources may be
present. Failure to do so may cause property
damage, personal injury or death.
WARNING
WARNING
1. Remove the wires from the auxiliary limit control
terminals.
2. Using an ohmmeter, test for continuity across the two
terminals. No reading indicates the control is open.
Push the red reset button, test again - if still open,
replace the control.
Testing Auxiliary Limit Control

Checking Flame Rollout Switch

A/GPGM3 units are equipped with a temperature-activated
manual reset control. This control is mounted to the
manifold assembly and is wired in series with the auxiliary
limit and gas valve. The control is designed to open should
a flame roll out occur. An overfiring condition or flame
impingement on the heat shield can also cause the control
to open.
Rollout Protection on Burner Bracket
34