Relay Selection For The Pump Control Connection - A.O. Smith Water Heater 520 Direct Vent Indoor Service Manual

12-15. Relay selection for the pump control connection

The maximum current capacity of the 520 Indoor or 520 Outdoor pump control connection is 1 amp.
Before using any relay with the pump control, please check the specifications of that particular relay to
ensure that the current value through the coil will not exceed 1 amp.
For example:
To the right, there is a sample of relay
specifications from an arbitrary brochure. You
can select either the 120 VAC or 240 VAC relay,
because their current values are less than 1 A
(1,000mA).
Connect to this "pump" terminal
120 VAC
Thermal
220 VAC etc
relay
for relay
These components are NOT included with water
heaters and are external to the unit. They must
be acquired separately.
Power supply for relay
Normally 120 VAC
Power supply for Pump
120 VAC
220 VAC etc.
78
520 Indoor / 520 Outdoor Service Manual
Through this circuit, the maximum
current capacity is 1 A
CONFIDENTIAL
Ver. 1.00