XLT XD-9007A (ELEC Oven Version – C, AVI Hood Version – C) - Manual (Page 12)

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HOOD THEORY OF OPERATION (STD w/FS)
The first part of the Theory of Operation explains how electrical power is delivered to the
hood and initial sequences when the main operator switch is turned on. The remainder of the The-
ory of Operation section explains the function of components in alphabetical order. These compo-
nents are also listed on the schematic.
 Line voltage for Standard Hoods is assumed to be 208/240 VAC, 60 Hz. (1) Phase
 Line voltage for World & Australian Hoods is assumed to be 230 VAC, 50 Hz. (1) Phase
Power for the hood originates at building’s electrical service panel. A total of two (2) cir-
cuits are required; (1) is a single phase high voltage circuit for VFD/Fan circuit that connects to TS
1 terminals 1 & 2, and (2) is a single phase low voltage circuit for Fire Suppression circuits and
relays that connect to TS 2 terminals 23 & 24.
Switches mounted on the hood control lighting, VFD activation, Make Up Air (MUA) activation
and oven function. When S1 is activated voltage will be carried to the lights turning them on.
When XLT Ovens are installed with an AVI Hood, the Switch Relocation Cord (SRC) effectively
eliminates the Main Switch located on the oven and transfers control to the DPDT switches on the
hood. When S2-S4 switches are activated a contact on the back of the switch will allow a low volt-
age signal to be sent to the VFD signaling it to turn on to a set frequency, at the same time when
S2 is activated another contact switch will allow line voltage to be carried through the Switch Re-
location Cord (SRC) to the oven activating it. Also the S2 switch sends line voltage to R4 to acti-
vate a MUA relay coil which switches from Normally Open (NO) to Normally Closed (NC) and
completes the circuit to allow operation of the MUA unit.
The NO switch in the fire alarm system in the building needs to be connected to TS 2 terminals 13
& 14. When the alarm is activated it will supply line voltage to R3 making the relay switch from
NC to NO, disabling the lights and cooling fans. It will also send a signal to disable contacts for
oven power and R2. When the ovens shut off, the power is removed from R4-R6, removing power
from the MUA units. When line voltage is supplied to R2, the relay switches from NC to NO acti-
vating the VFD to run full speed.
CB - Circuit Breakers are used to protect electrical components. If a CB is tripped, eliminate the
cause and press the front to reset.
When any one of, or all of, the Hood Operator Switches (S2, S3, & S4) are turned on;
1. The Exhaust Fan Motor (M1) located on the roof will run.
2. The Variable Frequency Drive (VFD) will display a set value. The values are preset from the
factory and can be referenced in the I&O manual.
3. The ovens associated with the corresponding switches will turn on.