28 Wiring
Precautions for ON-OFF control by the relay
The control unit is equipped with CPU. Always start/stop the pump by the
STOP signal. Do not start/stop the pump by turning ON/OFF power be-
cause it may adversely affect CPU.
If there is no choice but to turn ON/OFF power, observe the following
points.
• Do not turn ON/OFF the power more than six times per hour.
• When using a relay for ON-OFF operation, its contact capacity should be
5A or more. Contact point may fail if contact capacity is less than 5A.
• If the contact capacity of 5A is used for the EHN, the maximum ON/OFF
operation is about 150,000 times. Use the relay with the contact capac-
ity of 10A or more when making ON-OFF operation over 150,000 times
or sharing a power source with a large capacity equipment. Otherwise a
contact may fail by surge voltage.
• Use non contact transistor relay as necessary (ex. OMRON G3F). See
manufacturer's catalogues for detail.
External input cable
Points to be checked
• Check that the main power is turned off.
The pump is still charged right after turning off power. Wait for one
minute before wiring.
Applicable cables
A cable diameter shall be 7.8mm.
Triplex cable: VCTF-3 1.25mm
2
Duplex cable: UL, CSA SJT 18AWG/2
* The use of a cable diameter other than 7.8mm results in improper connection and
reduced seal performance.
Summary of Contents for EHN-R
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