MR-AHU
Installation Sheet (TCON154 11/97) 3
Connecting the Output Devices
1.
Connect one lead of the control relays to TB5 – 1 through
TB5 – 6 (Output 1 through Output 6) as shown in Figure6,
“Output Device Connections”.
2.
Connect the other lead of the control relays to earth ground
as shown.
Note:
You must establish a proper earth ground connection
point prior to connecting wires to electrical equip-
ment.
•
Electrical Service Earth Ground wire must be
securely connected to the equipment chassis.
•
The 24 VAC transformer secondary lead must be
securely connected to the Electrical Service Earth
Ground wire.
•
The Electrical Service Earth Ground wire must be
connected to the ground terminal on the
controller power input terminal block, TB1 – 2
(Ground).
Connecting the Power Supply
1.
Connect the 24 VAC input lead from a separate, isolated 24
VAC transformer to TB1 – 1 (24 VAC, see Figure7, “Power
Connections”).
2.
Connect TB1 – 2 (Ground) to earth ground using 14-AWG
wire (2.1 mm
2
). TB1 – 2 connects to the same earth ground
connection as the neutral lead from the transformer.
Note:
Connecting TB1 – 2 to a chassis bonding post sepa-
rated by seams, welds, or fasteners in the metal
chassis could produce continuity ground faults.
Caution:
Applying 24 VAC power to any connectot other than
TB1 will cause component damage to the MR-AHU
circuit board.
Switch Settings
The DIP switch settings define the sub-LAN address and basic
configuration of the unit. Define the sub-LAN address using
switches 1 – 5 to set an address ranging from 0 to 31. The value
is the accumulated value of switches 1 – 5 when set to the ON
position (refer to Table 1). The ON position of the switch is away
from the “Open” label on the switch base. The operational
configuration can be initially set using the DIP switch settings in
Table 2. For information concerning specific application
configurations refer to TCON153,
Application Specific Controller,
MR-AHU Installation Guide
.
Figure 6. Output Device Connections
GROUND
OUTPUT 6
OUTPUT 5
OUTPUT 4
OUTPUT 2
OUTPUT 3
OUTPUT 1
Aux/Fan/Heat
Relay or actuator loads
24 VAC @ 0.5 A each, 2.0 A maximum Total
TB5
Earth
Ground
1234567
Damper
H2
H1
Fan
C1
C2/H3 or C2 (See Note)
24VAC 0.5A EACH 20A TOTAL
TRIAC OUTPUTS
Note: MR-AHUs with binary load
AHU_2200 and later do not
support a third stage of heating.
Figure 7. Power Connections
LAN
P1
TB1
TB2
AC PWR
12
12
LAN +
LAN
PORT
LAN –
24V
GROUND
PWR
Earth
Ground
Line Voltage 24 VAC
24 VAC Transformer
