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292447-YIM-A-0507
Unitary Products Group 47
Figure 31: Reheat Control Board
Electric Heating Sequence Of Operations
The following sequence describes the operation of the electric
heat section.
Two-stage heating:
a. Upon a call for first stage heat by the thermostat, the
heater relay (RA) will be energized. After completing the
specified fan on delay for heating, the UCB will energize
the blower motor. If the second stage of heat is required,
heater relay (RB) will be energized. After completing the
specified fan on delay for heating, the UCB will energize
the blower motor.
b The thermostat will cycle the electric heat to satisfy the
heating requirements of the conditioned space.
Electric Heat Operation Errors
Temperature Limit
If the UCB senses zero volts from the high temperature limit,
the indoor blower motor is immediately energized.
This limit is monitored regardless of unit operation status, i.e.
the limit is monitored at all times.
If the temperature limit opens three times within one hour, it will
lock-on the indoor blower motor and a flash code is initiated
(See Table 30).
R
Y1
Y2
G
W1
OCC
C
W2
P4
P5
P6
P3
COM
HGRR
HGR
HUM
K1
K2
K4
K3
`
MODE
SELECTION
JUMPER
DEHUMIDISTAT
HARNESS
CONNECTION