Service manual

SERVICING
28
Symptom Fault Description(s) Possible Causes Corrective Action Cautions and Notes
- M otor rocks slightly
when st art ing .
- This is no rmal start -up f o r
variable speed moto r.
---- ---- ----
- No mo vement.
- Manual disconnect switch off or door switch open.
- B lown f use o r circuit breaker.
- 24 Vac wires miswired.
- Unseated p ins in wiring harness connect o rs.
- Bad motor/control module.
- M o isture present in mot o r o r co ntrol mo d ule.
- Check 230 Vac power at motor.
- Check lo w vo lt age (24 V ac R t o C) at mot o r.
- Check lo w vo lt age co nnect ions (G, Y , W , R, C) at mo t o r.
- Check f o r unseated p ins in connect o rs o n mot o r harness.
- Test with a t empo rary jump er b et ween R - G.
- Check m
- Turn power OFF prior to repair. Wait 5
minutes af t er d isconnecting p ower b efo re
op ening mot o r.
- Handle electro nic mot or/ cont ro l wit h care.
- Motor rocks, but won't start.
- Lo o se mot or mo unt .
- B lower wheel no t tight o n mo t o r shaft .
- Bad motor/control module.
- Check for loose motor mount.
- M ake sure blower wheel is tight on shaft.
- Perfo rm mo t o r/ control rep lacement check, EC M mo t ors o nly.
- Turn power OFF prior to repair. Wait 5
minutes af t er d isconnecting p ower b efo re
op ening mot o r.
- Handle electro nic mot or/ cont ro l wit h care.
- M otor oscillates up &
dow n while being
tested off of blower.
- It is normal for motor to oscillate
wit h no lo ad o n shaf t.
---- ---- ----
- V aries up and d o wn o r int ermittent .
- V ariat io n in 23 0 Vac to mot o r.
- Unseated p ins in wiring harness connect o rs.
- Erratic CFM co mmand f ro m " BK" terminal.
- Imp rop er t hermo stat co nnection o r sett ing .
- M o ist ure present in mot o r/ co nt ro l mo d ule.
- Check line vo lt ag e fo r variatio n o r " sag" .
- Check lo w vo lt age connect ions (G, Y , W , R, C) at
moto r, unseat ed p ins in motor harness connecto rs.
- Check-o ut system co nt ro ls - Thermo st at .
- Perform M oisture Check.*
- Turn power OFF prior to repair.
- " Hunts" o r " puf f s" at high CFM
(speed ).
- Incorrect or dirty filter(s).
- Incorrect supply or return ductwork.
- Incorrect blo wer sp eed sett ing.
- Does remo ving p anel or filt er red uce " puf fing" ?
- Check/ rep lace filter.
- Check/correct duct restrictions.
- Adjust to correct blower speed setting.
- Turn power OFF prior to repair.
- Stays at low CFM despite system
call f o r co o l or heat CFM .
- 24 Vac wires miswired or loose.
- " R" missing/ no t connect ed at mo t o r.
- Fan in delay mode.
- Check lo w vo ltage (Thermo stat) wires and co nnectio ns.
- V erify fan is no t in d elay mo de - wait unt il delay co mp lete.
- Perfo rm mo t o r/ control rep lacement check, EC M mo t ors o nly.
- Turn power OFF prior to repair. Wait 5
minutes af t er d isconnecting p ower b efo re
op ening mot o r.
- Handle electro nic mot or/ cont ro l wit h care.
- St ays at high CFM .
- " R" missing/ no t connect ed at mo t o r.
- Fan in delay mode.
- Is fan in delay mode? - wait until delay time complete.
- Perfo rm mo t o r/ control rep lacement check, EC M mo t ors o nly.
- Turn p o w er OFF prior to repair. W ait 5 minutes
aft er d isco nnecting p o wer b efore opening mo t o r.
- Handle electro nic mot or/ cont ro l wit h care.
- B lower wo n't shut o f f . - Current leakag e f rom co ntro ls int o G, Y , o r W . - Check f o r Triac switched t 'stat or solid st ate relay. - Turn power OFF prior to repair.
- Air noise.
- High static creating high blower speed.
- Incorrect supply or return ductwork.
- Incorrect or dirty filter(s).
- Incorrect blo wer sp eed sett ing.
- Check/ rep lace filter.
- Check/correct duct restrictions.
- Adjust to correct blower speed setting.
- Turn power OFF prior to repair.
- Noisy blower or cabinet.
- Lo o se blower ho using, p anels, et c.
- High static creating high blower speed.
- A ir leaks in d uctwork, cab inets, or p anels.
- Check f o r loose b lo wer housing, p anels, et c.
- Check f o r air whist ling t hru seams in d uct s, cabinet s o r
panels.
- Check f o r cabinet / d uct d ef o rmat io n.
- Turn power OFF prior to repair.
- " Hunts" o r " puf f s" at high CFM
(speed ).
- High static creating high blower speed.
- Incorrect or dirty filter(s).
- Incorrect supply or return ductwork.
- Incorrect blo wer sp eed sett ing.
- Does remo ving p anel or filt er red uce " puf fing" ?
- Check/ rep lace filter.
- Check/correct duct restrictions.
- Adjust to correct blower speed setting.
- Turn power OFF prior to repair.
- Evidence of M oisture.
- M otor failure or malfunction has
occurred and mo ist ure is
present .
- M o ist ure in mot o r/ co nt ro l mo dule. - Replace mot o r and p erf orm M oisture C heck.*
- Turn p o w er OFF prior to repair. W ait 5 minutes
aft er d isco nnecting p o wer befo re o pening mo to r.
- Handle electro nic mot or/ cont ro l wit h care.
- Connect o rs are o riented " do w n" (or as reco mmended b y equipment manufacturer). - A rrang e harnesses wit h " drip loop " under moto r.
-
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Note:
Y ou must use the co rrect rep lacement control/mo t or mo d ule since they are f act o ry p rog rammed fo r specific o p erating mo d es. Even t ho ugh they lo o k alike, diff erent mo dules may have complet ely diff erent funct ionality. The ECM variable
speed mo to rs are c
Troubleshooting Chart for ECM Variable Speed Air Circulator Blower Motors
- M otor won't start.
- M otor starts, but runs
errat ically.
- Excessive noise.