E 2004
FILTERS
KITS AND ACCESSORIES
504,903M
07/04
HEPA INTERLOCK KIT
INSTALLATION INSTRUCTIONS FOR HEPA INTERLOCK KIT (X2680)
TO BE USED WITH HEPA BYPASS AIR FILTRATION SYSTEM
Shipping & Packing List
Package 1 of 1 contains the following:
1 − Current sensing relay (X4421)
1 − 24V AC coil relay (56L68)
1 − Mounting bracket
1 − 18 AWG black wire with two female insulated spade
connectors
2 − #8 − 32 X 3/8" screws
1 − 1/2" strain relief
3 − Wire ties
2 − 1/4" spade terminals for low voltage connection
Shipping Damage
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
Application
Use this HEPA interlock kit (X2680) to cycle the HEPA
bypass air filtration system (UL−listed HEPA series) with
the air handling unit (UL−listed CB Series or CSA−certified
G Series).
Installation
6 − Disconnect the blue wire from the on/off switch.
Connect the blue wire to terminal 5 on the 24V AC coil
relay. See figures 2 and 3.
7 − Connect one end of the provided black wire to terminal
7 on the 24V AC coil relay. Connect the other end of
the black wire to the center prong of the on/off switch.
See figures 2 and 3.
8 − Remove the snap hole plug and cut a hole in the
insulation in front of the hole. See figure 3.
9 − Insert a field−supplied two−wire thermostat cable
through the hole.
10 − Connect one end of the thermostat cable to the A and
B terminals of the 24V AC coil relay.
11 − Use two of the provided wire ties to bundle the high
voltage wires separately from the thermostat wires
(24V). Make sure that none of the wires touch the
blower wheel.
12 − Use the remaining wire tie to bundle the thermostat
wires (24V) together. Ensure that the thermostat wires
remain separate from the high voltage wires. Make
sure that none of the wires touch the blower wheel.
13 − Install the strain relief fitting around the thermostat
cable, and insert the strain relief through the hole.
Motor Mounting Bracket
WARNING
ON/OFF
SWITCH
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at disconnect switch(es). Unit may have multiple
power supplies.
1 − Disconnect the electrical power from the HEPA filter
and air handler.
2 − Remove the HEPA filter lid.
3 − Unscrew the two motor bracket screws that are across
from the on/off switch. See figure 1.
4 − Secure the L−shaped mounting bracket to the HEPA
filter bracket. See figure 3.
5 − Use the provided screws to secure the 24V AC coil
relay to the L−shaped bracket (label side up). See
figure 3.
07/04
*2P0704*
Page 1
SCREWS
Figure 1
504,903M
*P504903M*
24V AC Coil Relay (K209) Terminals
IMPORTANT
CONNECT
TO BLUE
WIRE
CONNECT
TO BLACK
WIRE
Low AC voltage (mV) may be present at the 24V AC
coil relay A" terminal when the blower motor is off.
This is normal for solid−state devices.
14 − Disconnect power from the air handler. Remove the
unit access panel.
15 − Locate the common (neutral) wire which is connected
to the blower inside the air handler. Disconnect the
common (neutral) wire and pass the end of the wire
through the opening in the solid−state current sensing
relay. Reconnect the wire to the common terminal on
the blower.
16 − Either secure the current sensing relay close by using
a field−provided screw or allow the current sensing
relay to hang from the common wire.
17 − Use a wire nut to connect one wire from the current
sensing relay (K38) to one of the thermostat cable
wires. See figure 5.
18 − Connect the other wire from the current sensing relay
to the R terminal on the air handler terminal block. See
figure 5.
19 − Connect the remaining thermostat cable wire to the C
terminal of the air handler terminal block. See figure 5.
CONNECT TO
THERMOSTAT CABLE
Figure 2
24V AC Coil Relay (K209)
24V AC
COIL
RELAY
SNAP HOLE
PLUG
ON/OFF
SWITCH
HEPA Interlock Kit Field Wiring
Air Handler Low
Voltage Terminal Strip
HEPA FILTER
BRACKET
K28
BLACK
WIRE
L−SHAPED
BRACKET
BLUE
WIRE
RC
Figure 3
Common
Lead
HEPA Interlock Kit Schematic Diagram
Common
Low
Air Handler
Blower
High
Common
Lead
HEPA
Bypass
System
Current Sensing
Relay
Blower
Thermostat
Wire
Figure 5
Turning Power on to the Air Handler
1 − Replace the air handler access panel.
2 − Restore electrical power to the air handler.
Turning Power on to HEPA Filter
1 − Replace the HEPA filter lid.
2 − Reconnect the power plug to a grounded 120V, 60Hz
outlet.
3 − Turn on the HEPA filter.
Figure 4
Page 2