Maintenance & Troubleshooting
(continued)
Look for oil leaks or stains on or around all braze joints and refrig-
9.
erant lines. The presence of oil here indicates a potentially serious
problem
(such as a refrigerant leak)
.
Inspect and clean the drain pan and drain line(s). The use of an
10.
anti-fungicide tablet to keep the condensate system free from
bacterial contaminants is recommended.
Check the pitch of the unit. Over time the building and equipment
11.
may settle, causing a shift in the direction of the condensate flows.
Ideally the unit should pitch a minimum of 5°
(at least
½”
)
to the
outside to allow for proper drainage.
Check weep holes along rear flange of the base pan to ensure they
12.
are free of debris.
Check to ensure the seal around the unit is not broken or damaged.
13.
NOTICE
Air leaks may make the conditioned area uncomfortably drafty
or produce noises. Visually inspect the foam gasket between
the wall and the unit, especially taking note of the separation
between the air inlet for the condenser and the condenser coil
discharge. These two areas must be sealed off from each other.
If you experience poor cooling operation or erratic operation,
check for air recirculation at the condenser coil.
Replace the access panels and reconnect the electrical power.
14.
Test the unit operation.
15.
Heat pump units — temporary emergency
heating mode
DANGER
Electrical shock hazard
— Disconnect power to the
RetroAire replacement PTAC/PTHP before servicing or ac-
cessing the control compartment. Failure to do so could result
in severe personal injury or death.
Should the heat pump fail, the control board can be forced
into electric heat mode.
This is a temporary solution until
the heat pump system can be repaired.
Locate the circuit board in the control section of the unit.
1.
Locate the terminals where the outdoor sensor connects to the
2.
circuit board.
Using a small needle nose type pliers, disconnect one side of the
3.
Troubleshooting sensors
DANGER
Electrical shock hazard
— Disconnect power to the
RetroAire replacement PTAC/PTHP before servicing or ac-
cessing the control compartment. Failure to do so could result
in severe personal injury or death.
See for the location of senor connections to the control board.
1.
If temperature response of the indoor or outdoor sensor is not
2.
correct, disconnect the sensor from the control board and check
the sensor resistance . Replace the sensor if its resistance is not
close to the values in the table.
Sensor resistance values
Table 1
Resistance, Kohms
77 (25°C)
10.0 K
50 (10°C)
19.9 K
35 (1.6°C)
30.0 K
30 (-1.1°C)
34.4 K
Sensor connections on control board
Figure 15
Indoor sensor connections
Outdoor sensor connections
sensor from the circuit board. A 2-stage thermostat will provide
Emergency heat.
This will appear to the circuit board as an outdoor coil freeze
4.
condition there-by energizing the electric resistance heater on
the call for heat.
See "Manual Reset Limit Switch" (
5.
Figure 14, page 21) for resetting
the limit switch if needed.
Replacement Packaged Terminal Air-Conditioning / Heat Pump
• Installation, Operation, and Maintenance Manual •
The Right Fit for Comfort
22
P/N 240008639, Rev. B [8/16/2011]
