Sterling ME - Manual (Page 23)

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PROBLEM PROBABLE CAUSE SOLUTION
6. Belts mismatched Belts improperly tensioned, causing Replace belts and tension drive with slack of each
after service
more stretch of some belts than others. belt on the same side of the drive.
Old belts and new belts used Replace with new belts.
on same drive.
Different brand name belts used Replace with a set of Machine Matched Belts.
on same drive.
Driver and driven shafts shifted Realign drive.
from parallel.
Belt cord section damaged during Replace belts and install properly.
installation.
7. Drive fails to adjust Fretting corrosion (drive allowed to Driver pulley must be disassembled,
operate at one speed over a period cleaned and lubricated, then
of time). reassembled.
TROUBLESHOOTING GUIDE
DX COOLING COIL
PROBLEM PROBABLE CAUSE SOLUTION
1. No or Insuffi cient Coil icing. a. Low liquid line pressure.*
Cooling
b. Thermal expansion valve.**
c. Low air fl ow across coil.
Air binding. Purge and charge system.
Thermal expansion valve.** a. Bulb mounted at incorrect location.
b. Bulb not secured properly.
Insuffi cient air fl ow. a. See air blower troubleshooting.
b. Clogged coil
Air bypassing coil. Caulk safe off.
Undersized system, demand Replace system.*
exceeding cooling system capacity.
Too much outside air. Check outside air dampers.
Refrigerant leak. Determine leak location and correct.
Low liquid pressure. Determine cause and correct.*
2. Water in Conditioned Air Exceeding coil face velocity - 600 fpm. Reduce unit air fl ow.
Drain pan p-trap clogged. Clean pan and p-trap.
* Refer to condensing unit installation and service manual.
**Refer to thermal expansion valve installation instruction.