Thomas & Betts BE User Manual
Mfg P/N 98807 Rev 8, Page 27
42. Troubleshooting
TRO UBLE
PRO BABLE C AUS E
REMEDY
Ve n te r m otor wi l l
n ot start
n ot start
1. No power t o unit .
1. T urn on power, check supply fuses, or circuit breaker. If unit is equipped wit h
unit -mount ed disconnect swit ch, check circuit breaker (See P aragraph 11).
unit -mount ed disconnect swit ch, check circuit breaker (See P aragraph 11).
2. No 24 volt power t o vent er relay.
2. T urn up t hermost at ; check cont rol t ransformer out put .
3. Vent er relay defect ive.
3. Replace relay.
4. Defect ive mot or or capacit or.
4. Replace mot or or capacit or.
Pi l ot wi l l n ot l i gh t
1. Manual valve not open.
1. Open manual valve.
(spark i gn i ti on
2. Air in gas line.
2. Bleed gas line.
syste m )
3. Dirt in pilot orifice.
3. Remove and clean wit h compressed air or solvent (do not ream).
4. Gas pressure t oo high or t oo low.
4. Adjust supply pressure. (See P aragraph 10).
5. Kinked pilot t ubing.
5. Replace t ubing.
6. P ilot valve does not open.
6. If 24 volt available at valve, replace valve.
7. No spark:
7.
a) Loose wire connect ions
a) Be cert ain all wires connect ions are solid.
b) T ransformer failure.
b) Be cert ain 24 volt s is available.
c) Incorrect spark gap.
c) Maint ain spark gap at .100".
d) Spark cable short ed t o ground.
d) Replace worn or grounded spark cable.
e ) Spark elect rode short ed t o ground.
e ) Replace pilot if ceramic spark elect rode is cracked or grounded.
f) Draft s affect ing pilot .
f) Make sure all panels are in place and t ight ly secured t o prevent draft s at pilot .
g) Ignit ion cont rol not grounded.
g) Make cert ain ignit ion cont rol is grounded t o furnace chassis
h ) Fault y ignit ion cont roller.
h ) If 24 volt is available t o ignit ion cont roller and all ot her causes have been
eliminat ed, replace ignit ion cont rol.
eliminat ed, replace ignit ion cont rol.
8. Opt ional lockout device int errupt ing cont rol
circuit by above causes.
circuit by above causes.
8. Reset lockout by int errupt ing cont rol at t hermost at .
9. Fault y combust ion air proving swit ch.
9. Replace combust ion air proving swit ch.
Pi l ot l i gh ts, m ai n
1. Manual valve not open.
1. Open manual valve.
val ve wi l l n ot ope n 2. Main valve not operat ing.
2.
(S park Ign i ti on
syste m )
syste m )
a) Defect ive valve.
a) If 24 volt is measured at valve connect ions and valve remains closed, replace
valve.
valve.
b) Loose wire connect ions.
b) Check and t ight en all wiring connect ions.
3. Ignit ion cont rol does not power main valve. 3.
a) Loose wire connect ions.
a) Check and t ight en all wiring connect ions.
b) Flame sensor grounded. (P ilot light s - spark
cont inues)
cont inues)
b) Be cert ain flame sensor lead is not grounded or insulat ion or ceramic is not
cracked. Replace as required.
cracked. Replace as required.
c) Gas pressure incorrect .
c) Set supply pressure at 5" w.c. t o 14" w.c. for nat ural gas and 11" w.c. t o 14"
w.c. for propane gas.
w.c. for propane gas.
d) Cracked ceramic at sensor.
d) Replace sensor.
e ) Fault y ignit ion cont roller.
e ) See P aragraph 33. If all checks indicat e no ot her cause, replace ignit ion
cont roller. DO NOT AT T EMP T T O REP AIR IGNIT ION CONT ROLLER.
cont roller. DO NOT AT T EMP T T O REP AIR IGNIT ION CONT ROLLER.
T HIS DEVICE HAS NO FIELD REP LACEABLE P ART S.
No h e at (He ate r
1. Incorrect manifold pressure or orifices.
1. Check manifold pressure (See P aragraph 10).
O pe rati n g)
2. Cycling on limit cont rol.
2. Check air t hroughput (See P aragraph 15).
3. Improper t hermost at locat ion or adjust ment . 3. See t hermost at manufact urer's inst ruct ions.
C ol d ai r de l i ve re d
1. Fan cont rol improperly wired
1. Connect as per wiring diagram.
O n S tart-u p
2. Defect ive fan cont rol.
2. Replace fan cont rol.
Du ri n g O pe rati on
3. Incorrect manifold pressure.
3. Check manifold line pressure (See P aragraph 10).
Motor wi l l n ot ru n
1. Circuit open.
1. Check wiring and connect ions. .
2. Fan cont rol inoperat ive.
2. Replace fan cont rol.
3. Defect ive mot or or capacit or.
3. Replace mot or or capacit or.
Motor tu rn s on
1. Fan cont rol improperly wired.
1. Connect as per wiring diagram.
an d off wh i l e
2. Defect ive fan cont rol.
2. Replace fan cont rol.
bu rn e r i s ope rati n g
(S e e m otor cu ts ou t
(S e e m otor cu ts ou t
3. P oor cont act bet ween fan cont rol and heat
exchanger t ube. Surface cont act is required.
exchanger t ube. Surface cont act is required.
3. Check for bent mount ing or loose mount ing screws.
on ove rl oad
4. Mot or overload device cycling on and off.
4. Check mot or load against mot or rat ing plat e. Replace mot or if needed.
be l ow)
5. Low ambient t emperat ure (less t han 40
o
F)
causing false cycling.
5. Inst all fan delay relay kit (See P aragraph 17.)
Fan m otor cu ts
1. Low or high volt age supply .
1. Correct elect ric supply.
ou t on ove rl oad
2. Defect ive mot or.
2. Replace mot or.
3. P oor air flow.
3. Clean mot or, fan and fan guard.
4. Defect ive bearing or lubricat ion.
4. Lubricat e bearings or replace mot or.
Bl owe r m otor
1. Improper mot or pulley and/or adjust ment .
1. See inst ruct ions in P aragraph 14.
cu ts ou t on
2. Improper st at ic pressure in t he duct syst em.
2. Adjust duct syst em dampers.
ove rl oad
3. Low volt age.
3. Check power supply.