Friedrich WallMaster 2009 Service Manual page 38

Problem
Water "spitting"
into room
Problem
Excessive
moisture
Problem
T-stat or
thermistor
short cycles
Problem
Prolonged off
cycles (automatic
operation)
Problem
Outside water
leaks
36
Possible Cause
Sublimation:
When unconditioned saturated,
outside air mixes with conditioned
air, condensation forms on the
cooler surfaces
Downward pitch of installation is
too steep towards back of unit
Restricted coil or dirty fi lter
Possible Cause
Insuffi cient air circulation thru area
to be air conditioned
Oversized unit
Inadequate vapor barrier in building
structure, particularly fl oors
Possible Cause
Defective thermistor
T-stat differential too narrow
Plenum gasket not sealing,
allowing discharge air to short
cycle t-stat
Restricted coil or dirty fi lter
Possible Cause
Heat anticipator (resistor) wire
disconnected at t-stat or system
switch
Heat anticipator (resistor) shorted or
open
Partial loss of charge in t-stat bulb
causing a wide differential
Defective thermistor
Possible Cause
Evaporator drain pan cracked or
obstructed
Water in compressor area
Obstructed condenser coil
Fan blade/slinger ring improperly
positioned
Action
Ensure that foam gaskets are installed in
between window panes & in between the
unit & the sleeve. Also, ensure that fresh
air/exhaust vents (on applicable models) are in
the closed position & are in tact
Follow installation instructions to ensure that
downward pitch of installed unit is no less than
1/4" & no more than 3/8"
Clean & advise customer of periodic cleaning
& maintenance needs of entire unit
Action
Adjust louvers for best possible air circulation
Operate in "MoneySaver" position
Advise customer
Action
Replace thermistor or electronic control board
Replace t-stat
Check gasket. Reposition or replace as
needed
Clean & advise customer of periodic cleaning
& maintenance needs of entire unit
Action
Refer to appropriate wiring diagram
Disconnect plus from outlet. Remove resistor
from bracket. Insert plug & depress "COOL"
& "FAN AUTOMATIC" buttons. Place t-stat to
warmest setting. Feel resistor for temperature.
If no heat, replace resistor
Replace t-stat
Replace thermistor or electronic control board
Action
Repair, clean or replace as required
Detach shroud from pan & coil. Clean &
remove old sealer. Reseal, reinstall & check
Use pressure wash or biodegradable cleaning
agent to clean
Adjust fan blade to 1/2" of condenser coil fi n
pack