29
Temco DV5200, DV6400 Series
77531
System Checks
(continued)
Defective thermocouple.
Verify that thermocouple is not kinked or damaged. Check
(mv Plus systems)
open circuit voltage of thermocouple. Voltage should be
between 18mv and 28mv. If voltage is less than 14mv,
replace thermocouple.
Defective thermo-generator.
After the pilot has been lit for approximately three minutes,
(Millivolt system)
and only the thermo-generator wire connected to the main
operator head, measure the voltage across TPTH and TP.
This open circuit voltage should be between 500mv and
750mv. Tune the pilot adjustment screw until the mv reading
falls within these parameters. (Counter-clockwise increases
mv reading, clockwise decreases)
Defective safety magnet.
Verify operation of safety magnet in the following
(mv Plus systems)
manner.
(A) Depress and hold pilot button.
(B) Verify open-circuit thermocouple voltage as de
scribed in previous step.
(C) Reconnect thermocouple to valve.
(D) Measure the Millivoltage between the solder button
on the base of the safety magnet, and the valve
body. If the mv reading is above 6mv for vented
appliances, or 8.5 mv for un-vented appliances, and
the safety magnet does not hold, replace the valve.
(E) If closed circuit mv reading is the same as the open
circuit reading, the coil is electrically open. Replace
the valve.
Defective Safety Magnet
Verify operation of safety magnet in the following
(Millivolt system)
manner.
(A) Remove all wires from the terminals of the main
operator.
(B) Measure the electrical voltage between the termi
nals TPTH and TP. If the voltage is above 110mv
and the safety magnet does not hold, replace the
valve.
Pilot orifice blocked.
Replace orifice with a new orifice of the exact size and
type.
Pilot drops out.
Wrong pilot orifice.
Replace the orifice with a new orifice supplied specifi
cally for the appliance and gas type in question.
No gas to main burner Low gas pressure to appliance.
With the main burner functioning, adjust the inlet pres
sure regulator to supply gas to the appliance within the
design parameters of the appliance manufacturer.
(Typically 7”NG, 11”LPG).
Pilot not lit.
Light pilot and wait for thermo-generator to heat up
sufficiently to power the main operator. If pilot fails to
light, or hold, refer to above sections.
Control knob not in ON
Rotate OFF/PILOT/ON control knob to the ON position.
position.
Problem
Possible Cause
Solution
