Keating Of Chicago pre 2000 series Manual - page 15
1-800-KEATING
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GAS GRIDDLE - SERIES 2000
13
THERMOSTAT BULB PLACEMENT DETAIL
MILLIVOLT CHECK (FOR QUALIFIED SERVICE
TECHNICIANS ONLY)
The millivolt valve is a thermopile self-powered combina-
tion gas control. Before checking the millivolt system,
the following operations should be performed and
observations made:
1. A genuine Keating millivolt thermostat should be
used for millivolt operation.
2. The thermostat leads and all wire connections
should be cleaned and tightened to eliminate all un-
necessary resistance.
3. If pilot will not remain lit when gas valve knob is
released, check automatic pilot.
NOTE: The millivolt system and individual components may
be checked with a millivolt meter having a 1-1000MV range.
Conduct each check below by connecting meter test leads to
terminals as indicated. All readings are closed circuit.
(REFER TO CHART BELOW)
A. BURNER COIL CHECK
(“A” Reading. Thermostat contacts CLOSED - Gas Valve
knob “ON”. Main burner should come ON.)
1. If the reading is more than 100 millivolts and the
automatic valve still does not come one, replace the
valve.
2. If the closed circuit reading (“A” reading) is less
than 100 millivolts, determine cause for low reading
and proceed as follows:
B. THERMOPILE OUTPUT CHECK
(“B” Reading. Thermostat contacts OPEN - Main burner
OFF.)
1. Thermopile system - 325 millivolts minimum. If the
minimum millivolt reading is not obtainable,
readjust thermopile for maximum millivolt output.
If millivolt reading is still below minimum specifi ed,
replace thermopile.
C. THERMOSTAT RESISTANCE CHECK
(“C” Reading. Thermostat contacts CLOSED - Gas valve
knob “ON”. Main burner should be ON.)
1. If the “C” reading is above 80 millivolts, the
resistance in the system is excessive and must be
reduced. To correct:
a. Clean and tighten thermostat leads and
connections.
b. Shorten or replace thermostat lead wires.
c. Cycle thermostat rapidly (manually turn dial)
to clean contacts.
D. AUTOMATIC PILOT DROPOUT CHECK
1. Hold gas valve knob depressed in pilot position
until maximum output is observed. Then extinguish
pilot and observe meter.
2. Dropout of automatic pilot magnet (sound should
be audible) should occur between 120 millivolts
and 30 millivolts. If dropout occurs outside these
limits, change the valve.
CHECK
TO TEST
CONNECT METER LEADS
TO TERMINALS
THERMOSTAT
CONTACTS
METER READING
SHOULD BE:
A
MILLIVOLT SYSTEM CHECK
TP TH
CLOSED
100mV OR MORE
B
THERMOPILE OUTPUT
THTP TP
OPEN
BETWEEN 325–700mV
C
SYSTEM RESISTANCE CHECK
THTP TH
CLOSED
MEASURE LESS THAN 80mV
D
AUTOMATIC PILOT DROPOUT
THTP TH
OPEN
BETWEEN 120mV–30mV