Trane GRAA - DX Cooling Coil Troubleshooting; Cooling Performance Issues; Water in Conditioned Air

MUA-SVX003B-EN
47
Problem Probable
Cause
Solution
Driver and driven
shafts shifted from
parallel
Realign drive.
Belt cord section
damaged during
installation
Replace belts and install properly.
Drive fails to
adjust
Fretting corrosion
(drive allowed to
operate at one
speed over a
period of time)
Driver pulley must be disassembled, cleaned
and lubricated, then reassembled.
Troubleshooting Guide — DX Cooling Coil
Problem Probable
Cause
Solution
No or Insufcient
Cooling
Coil icing
1. Low liquid line pressure.*
2. Thermal expansion valve.**
3. Low air ow across coil.
Air binding Purge and charge system.
Thermal expansion
valve**
1. Bulb mounted at incorrect location.
2. Bulb not secured properly.
Insufcient air ow
1. See air blower troubleshooting.
2. Clogged coil
Air bypassing coil Caulk safe off.
Undersized
system, demand
exceeding cooling
system capacity
Replace system.*
Too much outside
air
Check outside air dampers.
Refrigerant leak Determine leak location and correct.
Low liquid pressure Determine cause and correct.*
Water in
Conditioned Air
Exceeding coil face
velocity - 600 fpm.
Reduce unit air ow.
Drain pan p-trap
clogged.
Clean pan and p-trap.
NNoottee:: *Refer to condensing unit installation and service manual.
**Refer to thermal expansion valve installation instruction.
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