Market Forge Industries ST-12-TGG, Installation, Operation And Maintenance Manual, Page: 19 / 40

Form No. S-4846 Rev. A 11/98
4-4
TABLE 4-2
ELECTRICAL FAULT ISOLATION GUIDE
FAILURE FAULT LOCATION
1. Will not operate in either CONSTANT STEAM or 60-MINUTE
TIMER positions.
2. Operating in CONSTANT STEAM position but not in 60-MINUTE
TIMER position.
3. Operates in 60-MINUTE TIMER position but not in CONSTANT
STEAM position.
4. Steam solenoid valve fails to open with indicator light on.
5. Indicator light off with steam solenoid valve open.
6. With indicator light on and steam solenoid valve open, timer dial
fails to turn.
7. Buzzer fails to sound at end of 60-MINUTE TIMER mode.
8. Steam flows continuously from boiler drain line.
a. Incoming power
b. Timer
c. Door interlock switch
d. Wiring
a. 60-minute timer
b. Wiring
a. Timer
b. Wiring
a. Solenoid valve coil
b. Wiring
a. Indicator light
b. Wiring
a. Compartment thermostatic switch
b. Constant steam position
c. Timer motor
d. Wiring
a. 60-minute timer contacts
b. Buzzer
c. Wiring
a. Thermostatic switch
b. Cold water solenoid valve
c. Wiring
4.3.2 Electrical Inspection
The first step in any electrical troubleshooting proce-
dure is a thorough physical inspection of all wiring con-
nections. To access electrical components, remove the
control panel as explained in Subsection 6.3.4.
WARNING
Before removing control panel or checking connec-
tions and wiring, be sure that the circuit breaker for
incoming power is OFF. When power is supplied,
all exposed terminals of the control panel carry
120 volts.
Check all wiring connections by hand to assure that
both ends of all connection points are tightly secured.
Use a screwdriver to tighten connection points. If neces-
sary, visually inspect all quick-disconnect terminals for
evidence of corrosion. Terminals in this condition should
be separated, cleaned with emery cloth until shiny, and
tightly reconnected.
4.3.3 60-Minute Timer
4.3.3.1 Timer Contacts
Defective timer contacts will result in failure of either
cooker compartment to operate. When this occurs, re-
4. TROUBLESHOOTING (cont’d.)