– 53 –
FAN
1140 rpm
900 rpm
550 rpm
Start
10 Min
HEATER
DUTY
CYCLE
100%
50%
To prevent damage to the heater, a duty cycle is
utilized. When the unit is ON, the fan will start up at
900 rpm when at Hi speed, and at 800 rpm when at
Low speed, with the heater at 50% duty cycle.
The fan speed will gradually decrease to 550 rpm at
10 min, but the control will monitor the current value
and increase the heater duty from 50% to 100%.
Once this has completed, the fan speed will increase
to the set fan speed.
Note:
• 10 minutes is the longest ramp-0up case and
won’t produce the 550 rpm in all cases.
• Typicle ramp-up time is 2-3 minutes, based on
starting temperatures of the heater. The colder
the heater the longer the ramp up time.
• The ramp-up mode is meant to reduce the
inrush current at heater startup to improve
heater life.
• Accurate heater amperage can only be
achieved after ramp up mode is completed.
• Ramp-up mode is completed when no additional
rise in heater amperge draw is detected.
• A
dirty
fi
lter will cause the heater to throttle
down prematurely, thus producing insuf
fi
cient
heat output.
Heater Test
With power disconnected and the heater wire
harness unplugged, check for resistance of each
individual heater:
Note:
Heater resistance test temperature at 68°F.
To remove the heater assembly:
1. Remove the room cabinet. (See
Room Cabinet.
)
2. Remove the 2 Phillips-head screws that attach
the control panel to the air conditioner. (See
Control Assembly
.)
3. Lift the control panel from the 2 top tabs. (See
Control Assembly
.) Position the control panel to
the right.
HEATER CHECKPOINT
HEATER
CONNECTOR
HEATER RESISTANCE
(OHMS)
208V/230V 265V
1.0 KW
PIN NO. 1-4, BK-BR 195 ± 35% 200 ± 35%
1.4 KW
PIN NO. 2-5, RD-YL 200 ± 35% 205 ± 35%
2.4 KW
PIN No. 3-6, WH-BL 75 ± 35%
85 ± 35%
4. Remove the control box cover. (See
Control Box
Components
.)
5. Cut off cable ties that bundle heater wiring
inside control box. Disconnect heater wiring
harness (6-pin) and fuse and thermal protector
harness (red and blue wires).
6. Remove the 3 Phillips-head screws that attach
the indoor fan cover to the air plenum.
7. Tilt the top of the indoor fan cover out and
remove it from the air plenum.
(Continued next page)
