5-565.1
20
(6) ignition controller – (oPt)
The ignition controller is factory installed in the duct furnace
electrical junction box with the spark ignitor and sensor located
on the burner.
For both natural and propane gas units, the ignition controller
is 100% shut-off with continuous retry. On a call for heat, the
system will attempt to light the pilot for 70 seconds. If the pilot
is not sensed for any reason, the ignition control will wait for
approx imately six minutes with the combination gas control
closed and no spark. After six minutes, the cycle will begin
again. After three cycles, some ignition controllers lockout for
approximately one hour before the cycle begins again. This will
continue indefinitely until the pilot flame is sensed or power is
interrupted to the system.
(8) control relay – (oPt)
The control relay is factory installed in the duct furnace
electrical junction box. The relay has a 24V coil with double-
pole, double throw (DPDT) contacts. Refer to the unit wiring
diagram for the function of the switching operation of the relay.
The two normally open and two normally closed contacts are
rated for a maximum of 30 amps @ 115V/1Ph.
(9) time delay relay – (std)
The time delay relay is factory installed in the duct furnace
electrical junction box. The time delay relay allows the gas
controls to operate for approximately 30 seconds before the
blower starts. This allows the heat exchanger a warm up period
so that the initial delivered air coming out of the ductwork is
not cool. The time delay relay also keeps the motor running for
approximately 30 seconds after the call for heat has been satis-
fied to remove the residual heat from the heat exchanger. For
single phase units below 2 Hp, the time delay relay controls the
motor directly. For single phase units 2 Hp and greater and all
three phase units, the time delay relay controls the motor starter.
(10) furnace low voltage terminal strip – (std)
The furnace low voltage terminal strip is located in the duct
furnace electrical junction box. The terminal strip is labeled
to match the electrical wiring diagram provided with the unit.
Low voltage labeling ranges from terminal numbers 1 to 79. All
field wiring connections should be made to the top side of the
terminals to prevent miswiring by modifying the factory wiring
which is made to the bottom of the terminal strip.
(12) furnace supply Power terminal strip – (std)
The furnace supply power terminal strip is located in the duct
furnace electrical junction box. The terminal strip is labeled
to match the electrical wiring diagram provided with the unit.
Supply power labeling ranges from terminal numbers 80 to 99.
All field wiring connections should be made to the bottom side
of the terminals to prevent miswiring by modifying the factory
wiring which is made to the top of the terminal strip.
(13) control step down transformer – (std)
The control step down transformer is located in the duct furnace
electrical junction box. The transformer is used to step down
the supply power (115V, 208V, 230V, 460V, 575V) to 24V. This
transformer is used to control the gas controls, damper actuator,
motor starter, etc. Refer to the unit model number to determine
the volt- amp (VA) capacity of the duct furnace. The 15th digit
indicates the VA (See Model Nomenclature).
(14) control relay – (oPt)
The control relay is factory installed in the electrical section.
See description of Option 8 for additional details.
(15) Blower low voltage terminal strip – (std)
The blower low voltage terminal strip is located in the
electrical section. The terminal strip is labeled to match the
electrical wiring diagram provided with the unit. Low voltage
labeling ranges from terminal numbers 1 to 79. All field wiring
connections should be made to the right side of the terminals to
prevent miswiring by modifying the factory wiring which is made
to the left side of the terminal strip.
oPtions
(16) dead front disconnect switch – (oPt)
The dead front disconnect switch is factory installed in the
electrical section. The disconnect switch is designed so that
it must be turned “OFF” before entry to the electrical control
cabinet can be obtained (See Figure 20.1). When in the “OFF”
position, power is disconnected to all unit wiring electrically
following the switch (See Warning). To open, see Figure 20.1.
For servicing the unit, the disconnect switch can be manually
overridden by using a wrench and turning the disconnect switch
shaft 90° clockwise (See Figure 20.1). Fusible and circuit breaker
switches available. For fusible switches, Class “J” time delay
fuses must be field provided matching the fuse size listed on the
Model Identification plate.
(17) step down transformer fuses – (oPt)
The transformer fuses are factory installed in the electrical section.
The fuses are included to protect the transformer. Fuses included.
(18) step down transformer – (oPt)
The step down transformer is factory installed in the eletrical
section. The transformer is required for power exhausted units
with a supply voltage of 460V/3Ph and 575V/3Ph.
(19) factory installed minimum Positioner – (oPt)
The factory installed minimum positioner is installed in the
electrical section and is used with a modulating damper actuator
to set the minimum percentage of outside air. The minimum
positioner dial is manually set between 0 to 100% resulting in a
2 to 10 VDC signal being sent to the damper actuator. When
used in conjunction with the Proportional Temp Controller, the
positioner sets the minimum outside air percentage and the
Proportional Temp Controller then modulates between the
minimum position and 100% outside air.
WARNING
When the dead front disconnect switch is in the “OFF”
position, supply power remains energized at the blower supply
power terminal strip and the top of the dead front disconnect
switch. When providing service on or near these terminals,
building supply power to the unit should be de-energized.
%
Belimo
60
80
100
40
20
0
figure 20.2 - minimum Positioner
figure 20.1 - dead front disconnect switch assembly
instruction lable
Handle opening
Stand-off Panel
Blower Electrical Section
(See warning)
Supply Power Terminals
(with door open)
To override turn shaft 90 C.W.
Handle opening
instruction table
Supply Power Terminals
(See Warning)
To override turn shaft 90° C.W.
(with door open)
Blower Electrical Section
Stand-off Panel
Pinch handle latch
(A) & handle (B)
together when
opening and
closing door
A
B
