Checking Transformer And Control Circuit; Checking Contactor And/Or Relays; Checking Contactor Contacts - Daikin M Series Service And Troubleshooting

SERVICING

Checking Transformer and Control Circuit

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.
A step-down transformer (208/240 volt primary to 24 volt
secondary) is provided with each package unit. This allows
ample capacity for use with resistance heaters.
Disconnect ALL power before servicing.
1. Remove control panel cover, or etc., to gain access
to transformer.
With power ON:
Line voltage now present
2. Using a voltmeter, check voltage across secondary
voltage side of transformer (R to C).
3. No voltage indicates faulty transformer, bad wiring, or
bad splices.
4. Check transformer primary voltage at incoming line
voltage connections and/or splices.
5. If line voltage available at primary voltage side of
transformer and wiring and splices good, transformer
is inoperative. Replace.
WARNING
WARNING
WARNING

Checking Contactor and/or Relays

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.
The compressor contactor and other relay holding coils are
wired into the low or line voltage circuits. When the control
circuit is energized the coil pulls in the normally open
contacts or opens the normally closed contacts. When the
coil is de-energized, springs return the contacts to their
normal position.
NOTE: Most single phase contactors break only
one side of the line (L1), leaving 115 volts to ground
present at most internal components.
1. Remove the leads from the holding coil.
2. Using an ohmmeter, test across the coil terminals.
If the coil does not test continuous, replace the relay or
contactor.

Checking Contactor Contacts

Single Phase
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. Disconnect the wire leads from the terminal (T) side
of the contactor.
2. With power ON, energize the contactor.
Line voltage now present
WARNING
WARNING
WARNING
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