Installation Sheet
25 Page
Installaon
Installaon Manual
EXTERNAL FAN MOTOR CONNECTION
This water heater can be connected to a external fan motor so that it can activate when the water heater
requires more combustion air. Refer to the following diagram and the instructions of the fan motor manu-
facturer. Disconnect the power supply from the water heater.
These components are NOT
included with the 910 model and
are external to the unit. They
must be purchased seperately.
Disconnect the power supply
from the water heater.
Failure to do so can result in
electrical shock.
WARNING
PUMP CONTROL CONNECTIONS
The 910 can be used to control a recirculation pump. Proper pump control helps to preserve the life of the
system and saves energy as well. The water heater pump control port is a “normally-open” dry contact,
and therefore needs additional components to properly control a recirculation pump. To control the
recirculation pump, connect the pump via a field supplied relay to the "pump terminal" on the 910 center
computer board as shown in the diagram below. (The pump terminal is essentially only a dry contact.
An external power supply and relays are required to operate the pump.) Please make sure the relays are
properly rated for the recirculation pump.
Using the 910 internal thermistors as a temperature control, the recirculation pump will only turn on
when recirculation is needed, depending on the control mode selected. See the next section.
In an Easy-Link System, the pump must be connected only to the Pump terminal in the PARENT
unit. If the pump is connected to any of the CHILD units, the pump will not work. These
components are NOT included with water heaters and are external to the unit. They must be
acquired separately.
NOTICE
-Pump control mode-
The 910 provides the four types of the pump control modes. The pump control modes are selected by changing
the Dip switches located on the upper bank of the center computer board. (See the following diagrams.)
A) Recirculaon Control: DIP SW No. 4 ON
Five minutes after the heater goes into
standby, the heater will activate the
recirculation pump. It will run the pump
for one minute, monitoring the water
temperature. The pump will stop if the
water in the circulation line has not
cooled more than 9 °F (5 °C) from the
set temperature. The heater will repeat
this process 30 minutes later. The pump
will continue to run if the water has
cooled more than 9 °F (5 °C) from the set
temperature until the line has reheated.
If the inlet thermistor detects the water
temperature has cooled more than 9 °F (5
°C) from the set temperature during the
standby period, it will activate the pump to
reheat the circulation loop.
Center computer board
In an Easy-Link System, this connection
must be made on the parent unit.
External fan motor
Pump control
terminals*
Fan motor control
terminals*
Connect to these terminals located
on the center computer board
Power supply
for external
fan motor
120VAC
240VAC
Power
supply
for
relays
120VAC
*Max voltage allowed on these terminals: 240VAC
Connect to the pump control
terminals*.
Power supply for relay
Power supply for
pump 120 VAC
220 VAC etc
120 VAC
220 VAC
etc for
relay
Thermal
relay
pump
These components are
NOT included with water
heaters and are external
to the unit. They must be
acquired separately.
*Max voltage allowed on these terminals: 240VAC