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The Boiler Supply and Return sensors can be installed
either as strap-on sensors or inserted into an immersion
well that is packed with thermally-conductive paste.
BOILER SUPPLY AND RETURN SENSORS
Both the Supply and Return Sensors should be installed
on the supply and return piping of the boiler for proper
operation of the AQ250 Control Panel. Even if the AQ250
is connected to a modulating condensing boiler with its
own supply and/or return sensors, the AQ250's sensors
should still be installed for the control to operate.
The Boiler Supply water sensor should be installed on the
supply piping close to the exit port of the boiler, using one
of the AQ12C11 strap-on sensors supplied with the
AQ250. See Fig. 6 on page 7.
The Boiler Return sensor should be installed on the return
piping as close to the entrance port to the boiler as
practical, using the other AQ12C11 strap-on sensor
supplied with the AQ250. The correct location is one that
will measure the temperature of all combined sources of
water returning back to the boiler.
Insulate strap-on sensors with pipe wrap to ensure
accurate boiler temperature sensing.
The Boiler Supply and Return water sensors come with 10
ft. (3m) of wire to minimize the need for splicing.
Fig. 6. Strap-on temperature sensor installation.
IMPORTANT
Do not run sensor wires parallel, or close, to
telephone, Ethernet, or power cables. Cross all
power, Ethernet, and telephone wiring at right
angles.
If sensor wires are located in an area with strong
sources of electromagnetic interference, or EMI,
(e.g., if sensor wires are run in the same electrical
chase as line voltage wiring) use twisted pair,
shielded cable, or run wires in a grounded metal
conduit.
This is important because the calculated
temperature - based on the sensor's resistance
reading - can be distorted by high EMI, potentially
causing the AQ250 to not operate properly.
If using shielded cable or conduit, connect the
shield wire to earth ground only at the AQ250
panel. Do not ground the shield or conduit at any
other location or electromagnetic shielding will be
ineffective. If shielded cable is used, Resideo
recommends the use of shielded cable with a
continuous ground plane, such as foil, with an
integral drain wire for bonding to earth ground.
System Demands Wiring
HEAT DEMAND
Wire the Heat Demand (terminals 7 and 8) to a system
setpoint demand (dry contact closure), such as a pool or
spa Aquastat®.
DOMESTIC HOT WATER (OPTIONAL)
If used, wire the DHW (terminals 9 and 10) to the Aquastat
or thermostat on the domestic hot water tank.
DHW priority allows only DHW heat for the first 30
minutes of a call for DHW and then allows the space
heating needs to be added in for the next 30 minutes. This
cycle continues until the call for DHW is satisfied.
NOTE: If the AQ250 is connected to a modulating con-
Low Voltage Outputs Wiring
BOILER
Wire the Boiler dry contact output (terminals 11 and 12) to
the T-T terminals on the boiler Aquastat or the boiler's
control panel. See Fig. 14 on page 11 for wiring
connections to a typical boiler Aquastat.
It is not necessary to use the T-T terminals if connecting to
a Triple Aquastat, since the signal to the Aquastat is
received from the ZR/ZC terminals. See Fig. 14 and Fig. 15
beginning on page 11 for line voltage connection to boiler
M13763
Aquastats.
These contacts are made any time the system has a
request for boiler operation. When this occurs, the
system's primary boiler pump comes on.
Communication Bus Wiring
All AQ2000 components communicate with each other on
the AQUATROL network using communication bus wiring.
This wiring must connect all AQ2000 components.
Otherwise, features that depend on this networked
communication (e.g., zone synchronization) will not
function.
The communication bus wiring is polarity insensitive. The
installer does not need to worry about a +ve or –ve
orientation of the wires. If there are two wires connected
between the B-B Bus Exp. In on one module and B-B Bus
Exp. Out on another module, there will be communication.
See example in Fig. 7 for how this wiring is to be installed.
7
AQ250 SERIES HYDRONIC CONTROL PANELS
densing boiler with built-in DHW management,
the DHW tank's Aquastat should be connected to
the AQ250's DHW (terminals 9 and 10). In this
case, the Aux Out contacts should be pro-
grammed (in Installer Mode settings) to close
when there's a call for DHW [EQUIPMENT
SETUP>AUXILIARY IO>AUX.OUT>
DHW]
68-0306—07
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