Troubleshooting - Temco DV1000N/P Installation And Operating Manual

NOTE: Before troubleshooting the gas control system, be sure external shut off is in the "ON" position.
WARNING: Before doing any gas control service work, remove glass front!
Table 1
Valve Type
NOVA MV Plus
System Checks
Problem
Pilot will not light.
Pilot will not hold.
76657

Troubleshooting

SIT Millivolt Valve
Main Operator
Minimum Voltage 145mV
Coil Resistance 2.25Ω ± 0.5Ω
Possible Cause
Air in gas lines.
Wrong inlet pressure.
Defective spark electrode.
Defective piezo wire.
Safety interlock function
engaged.
Wrong inlet pressure.
Pilot adjustment screw not
properly adjusted.
Thermocouple or
thermo-generator not
properly inserted into the pilot
housing
Thermocouple or
thermo-generator has film
build-up on tip.
Electrical resistance too high.
Temco DV1000/1200/1400 Series
Safety Magnet
Hold-in Current
Drop-out Current
Coil Resistance
Solution
Bleed all air from gas lines.
With the main burner functioning, adjust the inlet
pressure regulator to supply gas to the appliance
within the design parameters of the appliance manu-
facturer. (Typically 7"NG, 11"LPG).
Replace piezo wire if insulation is cracked or the tip
is corroded.
Verify that the spark gap between the pilot and the
electrode is correct.
Replace piezo wire if insulation is damaged, or the
wire is broken or corroded.
Allow thermocouple to cool until the mv drops below
the hold-in requirements of the safety magnet, (30
seconds or less). Re-light pilot.
With the main burner functioning, adjust the inlet
pressure regulator to supply gas to the appliance
within design parameters of the appliance manufac
turer. (Typically 7"NG, 11"LPG)
After the pilot has been lit for approximately three
minutes, and only the thermo-generator wire con-
nected to the main operator head, measure the volt-
age across TPTH and TP. This open circuit volt
age 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).
Make certain that the thermocouple and thermo-
generator are fully inserted and tightened into their
receptacles in the pilot head. The thermocouple
should be threaded into the valve hand-tight, plus
1/4 turn with wrench.
With the thermocouple and thermo-generator tips
cool, clean the upper 3/8" with a very fine emery
cloth.
Using a very fine emery cloth, clean thermo-genera-
tor and thermocouple connections at valve. Tighten
thermocouple into valve hand-tight, plus 1/4 turn
with a wrench.
Less than 285mA
Greater than 125mA
0.108Ω ± 0.003Ω
29