PRIMARY CIRCUIT WITH HVAC SYSTEM BLOWER OPERATING
• If there is no supply line voltage at the transformer input connections, correct
the fault at the dedicated power source or HVAC system power source.
• If there is supply line voltage at the transformer input connections and no
output voltage (24 volts nominal), the transformer is defective and must be
replaced.
• If there is transformer output voltage (24 volts nominal) and no output voltage
from the ON/OFF switch, the outage can be located by checking operation of
the safety interlock switch and the interconnecting wiring with a Multimeter.
Refer to Circuit Diagram, (pg. 22) to check operation of the switches.
PRIMARY CIRCUIT WITH HVAC SYSTEM BLOWER NOT OPERATING
Follow these steps to test for proper operation of the Power Supply Board,
ON/OFF Switch, and Safety Interlock Switch.
1. Ensure that the circuit controlling the HVAC system blower is in the OFF
position, and input power to the air cleaner is disconnected.
2. The power supply board has a built-in internal fuse to protect the 24V
transformer. The fuse can be checked visually by inspection. If the fine wire
inside of the fuse is broken, a fault exists in the 24V circuit. Do NOT replace
this fuse. The entire Power Supply Assembly must be replaced. The purpose
of the fuse in not to protect the power supply board, but to function as a
troubleshooting feature of the product and to protect the transformer from
damage.
3. If the fuse is NOT blown, check the ON/OFF switch and safety interlock
switch for proper engagement and operation. This can be completed using a
Multimeter with an OHM scale capable of reading 1.0 ohm.
4. Remove the fuse. Connect one Multimeter test lead to the test pin hole (J9)
located directly beside the wire that connects the ON/OFF switch to the power
supply board. Connect the other Multimeter test lead to the fuse connection
nearest the front panel.
5. Turn the ON/OFF switch to the ON position and depress the safety interlock
switch. The Multimeter should have the capability of reading levels as low as
1.0 ohm. Multimeter reading of 1.0 ohm or less indicates correct operation of
the ON/OFF switch and the safety interlock switch.
6. If the Multimeter ohm reading is greater than 1.0 ohm, begin the process of
elimination by moving the Multimeter test lead from the test pin hole (J9) to
the safety interlock switch terminal with the blue wire lead. Depress the safety
interlock switch. If the reading on the meter is greater than 1.0 ohm, the safety
interlock switch is defective and must be replaced. If the reading on the meter
is less than 1.0 ohm, the ON/OFF switch is defective and must be replaced.
Troubleshooting
21
For Qualified HVAC
Installer Only
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