Daikin DCH048 Series Service Instructions Manual page 69

SERVICING
S-9 CHECKING FAN RELAY CONTACTS
DCG:
The fan relays are incorporated into the control board. See
section S-313 for checking control board for single phase
gas models.
For 3 phase and belt drive models, the procedure for testing
the fan relay contacts will be the same as checking the
compressor contactor contacts (See section S-8).
DCC/DCH:
The Electronic Blower Time Delay Relay is used on PSC and
belt driven models.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
Checking EBTDR High Voltage Contacts
1. With power off, remove wires from terminals NC, COM,
and NO.
2. Using a VOM, check for resistance from NO to COM.
Should read open. Next, check for resistance from NC to
COM. Should read closed.
3. If not as above, replace EBTDR.
Checking EBTDR Contact Operation
With power on:
1. Set the thermostat to the fan "on" position.
2. Check for 24 volts at the C and G terminals of the
EBTDR.
3. If no voltage present, check fan circuit from thermostat.
If 24 volts present, proceed to step 4.
4. Using a VOM, check for line voltage from the purple wire
at the transformer (terminal 3 on 240 volt units, terminal
2 on 208 volt units) to terminal NO on the EBTDR. Should
read line voltage. If no voltage present, check line voltage
wiring in unit. If line voltage present, proceed to step 5.
5. Using a VOM, check for line voltage from the purple wire
at the transformer (terminal 3 on 240 volt units, terminal
2 on 208 volt units) to the COM terminal on the EBTDR.
Should read line voltage. If not as above, replace EBTDR.
PSC equipped, single phase model coolers and heat pumps
have an isolation relay with a 240 volt holding coil in addition
to the EBTDR.
WARNING
Disconnect ALL power before servicing.
Turn power off.
Testing relay holding coil
1. Remove the leads from the holding coil terminals 1 and
3.
2. Using an ohmmeter, test across the coil terminals 1 and
3. If the coil does not test continuous, replace the relay.
Testing relay contacts
WARNING
Disconnect ALL power before servicing.
Turn power off.
1. Using a VOM, test resistance across relay terminals 2
and 4. Should read open.
2. Turn power on.
3. Apply 240 volts to coil terminals 1 and 3.
4. Using a VOM, check for 240 volts from terminals 3 and
1 of relay. Should read 240 volts. In no voltage, check
wiring from heater kit to relay. If voltage present, proceed
to step 5.
5. Using a VOM, check for 240 volts from L1 at contactor to
terminal 4 of relay. Should read 240 volts. Next check
from L1 at contactor to terminal 2 of relay. Should read
240 volts.
If not as above, replace relay.
On the 5 ton units with the EEM motor, a standard fan relay
is used.
WARNING
Disconnect ALL power before servicing.
Turn power off.
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