Temco Tool 36RDVN - Manual (Page 27)

27
RDVN Series Direct Vent Gas Fireplace
20007628
Troubleshooting
SIT Millivolt Valve
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 Main Operator Safety Magnet
NOVA MV Plus Minimum Voltage 145mV Hold-in Current Less than 285mA
Coil Resistance 2.25Ω ± 0.5Ω Drop-out Current Greater than 125mA
Coil Resistance 0.108Ω ± 0.003Ω
Problem Possible Cause Solution
Pilot will not light. Air in gas lines. Bleed all air from gas lines.
Wrong inlet pressure. With the main burner functioning, adjust the inlet pressure
regulator to supply gas to the appliance within the design
parameters of the appliance manufacturer. (Typically 7”NG,
11”LPG).
Defective spark electrode. Replace piezo wire if insulation is cracked or the tip is cor-
roded.
Verify that the spark gap between the pilot and the electrode
is correct.
Defective piezo wire. Replace piezo wire if insulation is damaged, or the wire is bro-
ken or corroded.
Safety interlock function engaged. Allow thermocouple to cool until the mv drops below the hold-
in requirements of the safety magnet, (30 seconds or less).
Re-light pilot.
Pilot will not hold. Wrong inlet pressure. With the main burner functioning, adjust the inlet pressure
regulator to supply gas to the appliance within design
parameters of the appliance manufacturer. (Typically 7”NG,
11”LPG)
Pilot adjustment screw not After the pilot has been lit for approximately three minutes,
properly adjusted. 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).
Thermocouple or Make certain that the thermocouple and thermo-generator are
thermo-generator not properly fully inserted and tightened into their receptacles in the pilot
inserted into the pilot housing. head. The thermocouple should be threaded into the valve
hand-tight, plus 1/4 turn with a wrench.
Thermocouple or With the thermocouple and thermo-generator tips cool, clean
thermo-generator has film the upper 3/8” with a very fine emery cloth.
build-up on tip.
Electrical resistance too high. Using a very fine emery cloth, clean thermo-generator and
thermocouple connections at valve. Tighten thermocouple into
valve hand-tight, plus 1/4 turn with a wrench.
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.
System Checks