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See Tables 37-39 for additional troubleshooting
information.
Table 37 — ECM Troubleshooting
IMPORTANT: Always recover the refrigerant from the
system with suitable approved tools, recovery equipment,
and practices prior to attempting to remove or repair any
TXV.
IMPORTANT: Due to the hygroscopic nature of the
POE oil in Puron refrigerant (R-410A) and other environ-
mentally sound refrigerants, any component replace-
ment must be conducted in a timely manner using
caution and proper service procedure for these types of
refrigerants. A complete installation instruction will be
included with each replacement TXV/filter drier assem-
bly. It is of critical importance these instructions are
carefully understood and followed. Failure to follow
these instructions can result in a system that is contami-
nated with moisture to the extent that several filter drier
replacements may be required to properly dry the
system.
IMPORTANT: Repair of any sealed refrigerant system
requires training in the use of refrigeration tools and proce-
dures. Repair should only be attempted by a qualified ser-
vice technician. A universal refrigerant handling certificate
will be required. Local and/or state license or certificate
may also be required.
CAUTION
Disconnect power from unit before removing or replacing
connectors, or servicing motor. Wait 5 minutes after dis-
connecting power before opening motor.
FAULT DESCRIPTION SOLUTION
Motor rocks slightly when
starting
This is normal start-up for ECM.
Motor will not start No movement Check power at motor.
Check low voltage (24-vac R to C) at motor.
Check low voltage connections (G,Y, W, R, C) at motor.
Check for unseated pins in connectors on motor harness. See Fig. 40.
Test with a temporary jumper between R and G.
Check motor for tight shaft.
Perform motor/control replacement check.
Run moisture check. See Moisture Check section in Troubleshooting.
Motor rocks Check for loose or non-compliant motor mount.
Make sure blower wheel is tight on shaft.
Perform motor/control replacement check.
Motor oscillates up and down
while being tested off of blower
It is normal for motor to oscillate with no load on shaft.
Motor starts, but runs erratically Varies up and down or intermittent Check line voltage for variation or “sag.”
Check low voltage connections (G,Y, W, R, C) at motor, unseated pins in motor harness
connectors. See Fig. 40.
Check “Bk” for erratic cfm command (in variable speed applications).
Check system controls, thermostat.
Perform moisture check. See Moisture Check section in Troubleshooting.
“Hunts” or “puffs” at high cfm
(speed)
If removing panel or filter reduces “puffing,” reduce restriction or reduce maximum airflow.
Stays at low cfm despite system
call for cool or heat cfm
Check low voltage (thermostat) wires and connections.
Verify fan is not in delay mode. Wait until delay is complete.
Check to see if “R” is missing/not connected at motor.
Perform motor/control replacement check.
Stays at high cfm Check to see if “R” is missing/not connected at motor.
Verify fan is not in delay mode. Wait until delay is complete.
Perform motor/control replacement check.
Blower will not shut off Check to see if there is current leakage from controls into G, Y, or W. Check for Triac switched
thermostat or solid state relay.
Excessive noise Noisy blower or cabinet Determine if it is air, cabinet, duct, or motor noise.
Check for loose blower housing, panels, etc.
If high static is creating high blower speed, check for air whistling through seams in ducts,
cabinets, or panels.
If high static is creating high blower speed, check for cabinet/duct deformation.
“Hunts” or “puffs” at high cfm
(speed)
If removing panel or filter reduces “puffing,” reduce restriction or reduce maximum airflow.
Evidence of moisture Motor failure or malfunction has
occurred and moisture is present
Replace motor and perform moisture check. See Moisture Check section in Troubleshooting.
Evidence of moisture present
inside air mover
Perform moisture check. See Moisture Check section in Troubleshooting.