Belshaw Brothers TG 50 - Manual (Page 46)

November 1999 32 COUNTER TOP IMPINGER
Main Oven Fan Check if main oven fan is working. If not, refer to
"Oven Fan Will Not Run".
Temperature Control
Board Check for voltage input at the board. Turn the
temperature adjustment knob to the maximum
temperature position and check for voltage at the load
terminal. If present, and unit is not heating, refer to "Air
pressure switch" for next check. If no voltage is
present, proceed.
Thermocouple Sensor Check terminals, wiring, and proper location of the
sensor bulb. It must be in its spring holder located in
the inside, rear, lower right hand corner (viewed from
front) behind Finger #4. The thermocouple is a type J
and has one red lead (Neg.) and one white lead
(Pos.).WITH POWER ON AND THERMOCOUPLE
LEADS ATTACHED TO THE TEMPERATURE
CONTROL BOARD: Measure the D.C. millivolt output
of these leads. Refer to thermocouple chart in Section
D for proper readings. If these readings are not
achieved, replace the thermocouple.
Temperature Set
Potentiometer Disconnect the potentiometer leads from the board.
Place ohm meter test leads on the blue and green pot.
leads. Reading should be 1 K ohms. Place meter leads
across the blue and purple pot. leads and rotate knob
from high to low. Repeat on green and purple leads.
Check for even rise and fall of ohms reading to insure
that there are no open or dead spots in the
potentiometer. Check each lead to ground for shorts.
Replace Pot. if it does not meet the above test.
Hi Limit Thermostat-
Oven Cavity Terminals are normally closed, open at 660°F (350°C).
If open, push in reset button and retest. If thermostat
will not hold for maximum oven temperature, and oven
is not exceeding temperature dial setting, check for
proper location of capillary bulb in its spring holder. If
above checks okay, replace hi-limit thermostat.
Air Pressure Switch Check for voltage on both sides of the switch, if voltage
is present on one side only, check for air tube
blockage, adjust air switch, if above fails, replace
switch.
Heating Element Relay Check for voltage to the Relay coil and contacts. If
voltage is present and contactor will not activate,
replace the contactor. Check for voltage across relay
terminals.
Oven will not heat
Heater Element Check the amperage draw on each hot leg for proper
load. Check the rating plate for rating information. If
amp draw is low or high, check element for opens and
shorts.