Electric Defrost - Hussmann IMPACT RLT Technical Data Sheet

Fan and Heater Circuits - Electric Defrost (standard)
208V
1
2
3
120V P
OWER
14
16
13
120V POWER
Switch
17
OR
Defrost Termination
FIELD WIRED
Thermostat
DB
Low Temperature with

Electric Defrost

R R
1 2
Permanent Internal
Jumpers
DEFROST HEATERS
(208V)
Electric Defrost Sequence - Low Temperature
1. Power from the defrost contactor energizes Defrost Heaters and 208V Evaporator Fan Relay Coil (7). Relay Contacts open the fan
circuit and energizes the Drain Pan Heater.
2. If the Defrost Heater raises internal air temperature above 90°F, the Defrost Limit Thermostat (4) will open.
3. Temperature rise of the evaporator closes the Relay Control Thermostat (5) at about 35°F, energizing 120V A.S. Relay Coils (6).
These relays' contacts open the Frame and Door Heater Circuits, and prevent the Fan Circuit from energizing upon defrost
termination.
4. When Defrost Termination Thermostat ends defrost period, the defrost contactor opens the Defrost Heater and Evaporator Fan Relay
Coil Circuits. The Drain Pan Heater goes off.
5. Temperature fall of the evaporator opens the Relay Control Thermostat (5) at about 20°F, de-energizing 120V A.S. Relay Coils (6).
A.S. Relay Contacts close the Frame and Door Heater Circuits, and Fan Circuit.
P/N 0445823_B
Low Temperature
CIRCLED NUMBERS = PARTS LIST ITEM NUMBERS
R = Red P = Purple 2P = Purple (2 Bands) DB = Dark Blue B = Black
BR =Brown Y =Yellow OR = Orange W = White
THESE ARE MARKER COLORS (WIRE MAY VARY.)
R
Defrost Heater
8
R
120V
Fan Relay
Fan Relay
7
N.C.
COM
B
Fan Relay
7
N.O.
Y
Relay Control
B
6
A.S. Relay
COM
N.C.
B
B
N
EUTRAL
20
L
OR
2
DB
C.O.R.
Terminal Blocks in Raceway
R R B B R R B P
3 4 5 6 7 8 10 11
Removable External
Jumpers
HUSSMANN CORPORATION • BRIDGETON, MO 63044-2483 U.S.A. • WWW.HUSSMANN.COM
208V
Evaporator Fan
7
Relay Coil
1
3
C
8
7
R
Defrost Limit
6
B
O.O.R.
N.C.
6
1
Evaporator Fans
N.C.
Rod Heater (Drain) 9
A.S. Relay 6
5
Coil
3 1
C
C.O.R.
6
C
120V Fan
10
Relay Coil
Frame A.S. Heaters
11
P
Door A.S. Heaters
12
2P
2P B B B OR OR 2P P
12 13 14 16 17 20 21 22
FANS & A.S. LIGHTS
LIGHTS
(120V)
(120V) (Neutral)
208V
CAUTION: When multiplexing
4
merchandisers equipped with defrost
R
heaters, if branch circuit overcurrent
protection is larger than the
individual merchandiser's defrost
circuit load, then additional
supplemental overcurrent protection
may be required per NEC Articles
4
210 and 240.
5
B
N
EUTRAL
26
BR
Refer to Innovator Reach-In
Glass Door, Installation and
Service manual, P/N 0425683,
25
Y for Innovator door and frame
replacement parts.
24
W
22
P
Defrost Termination
Thermostat
21
2P
W Y BR
Dark Blue
24 25 26
FANS & A.S. (Neutral)
2
Refrigeration
Thermostat 3
(Optional)
Pink
} To
Condensing
Unit
5 of 6