Service; Ignition Control System; System Diagnostics; Electrical Servicing - A.O. Smith BTR 151 Instruction Manual

The installer may be able to observe and correct certain problems
which may arise when the unit is put into operation. HOWEVER,
it is recommended that only qualified service agents, using
appropriate test equipment, be allowed to service the heater.
As preliminary step, check wiring against diagram, check for
grounded, broken or loose wires. Check all wire ends to be sure
that they are making good contact.

ignition control system

Before calling your service agent, the following checklist should
be examined to eliminate obvious problems from those requiring
replacement or servicing.
• Check that "main manual gas shutoff valve" is fully open and
that gas service has not been interrupted.
• Check that after following the appliance OPERATIng
InSTRuCTIOnS, the "Top Knob" of the appliance gas valve
is in "On" position.
• Check electrical supply to the appliance for possible blown
(or tripped) fusing or power interruption. Also check the 3
amp fuse on the front of the digital thermostat (Fig. 2).
• Is the water temperature in tank below the thermostat dial
setting on the appliance thermostat (calling for heat)?
• It is possible that the high limit (E.C.O.) has functioned to
shut off the appliance. See High Limit page 7 - High Limit
Switch for reset procedure. Contact your service agent if
limit continues to function to shut off appliance.

system diagnostics

Your water heater is equipped with an ignition control that
incorporates a diagnostic system to assist in troubleshooting the
appliance. The indicator codes on the ignition control are as follows:

serVice

TABLE 8:
1 FlAsh System lockout (retries or cycles exceeded)
2 FlAshEs Pressure switch stuck close
3 FlAshEs Pressure switch stuck open
4 FlAshEs Open on high temperature limit switch (eco)
6 FlAshEs 115 volt AC power reversed (check polarity)
Low flame sense signal (make sure flame
7 FlAshEs
sensor is in burner flame)
8 FlAshEs Check igniter
continuous flash -> continuous flame sensed > 5 seconds
without gas valve
continuous on -> internal control failure - replace ignition control
control.
use this diagnostic system in conjunction with the table titled
"TROuBLESHOOTIng" and the "SEQuEnCE OF OPERATIOn"
to troubleshoot the appliance.

electrical serVicing

LABEL ALL WIRES PRIOR TO DISCOnnECTIOn WHEn
SERVICIng COnTROLS. WIRIng ERRORS CAn CAuSE
IMPROPER AnD DAngEROuS OPERATIOn.
VERIFY PROPER OPERATIOn AFTER SERVICIng.
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