Follow these steps to troubleshoot a Robertshaw Valve:
1.Complete System check: With the thermostat contacts closed and gas cock dial “ON”, main burner should ignite. If not, measure across TP and TH terminals. If the reading is more than 100 MV, replace the gas valve.
2.System Resistance Check: With the thermostat contacts closed and main burner “ON”, measure the millivolt reading between THTP and TH terminals. Reading should be less than 80MV. If not, recheck thermostat leads and connections. Replace with new or heavier gauge wires if necessary. If the reading is still greater than 80 MV, replace the thermostat.
THTP TH
Terminal 1
Terminal 3
TP
Terminal 2
Millivolt Operator Terminal
Panel
| Test |
|
| Meter |
|
| Meter Leads |
|
|
| Acceptable |
| |
|
|
| Setting |
|
| on Terminals |
|
|
| Results |
| ||
|
|
|
|
|
|
|
|
|
| ||||
1 |
|
| MV |
|
| TP | TH |
|
| Less than 100MV | |||
|
|
|
|
|
|
|
|
|
|
| |||
2 |
|
| MV |
|
| THTP | TH |
|
| Less than 80MV | |||
3 |
|
| MV |
|
| THTP | TP |
|
| ||||
3.Automatic Pilot Dropout Check: With the thermostat contacts open, depress gas cock knob with pilot lit until maximum millivolt output is observed between terminals THTP and TP. Extinguish the pilot and observe the meter. The sound of the pilot magnet dropping should be audible. The dropout should occur between 120MV and 30MV. If outside these limits, change the gas valve.
1.9.5 Improper Burner Functioning
The burner lighting on one side only may be caused by a missing or misaligned rear deflector target or improper burner manifold pressure. Clogged burner orifices are usually the cause of gaps in burner firing.
Fluctuating flame intensity is normally caused by either improper or fluctuating incoming gas pressure, but may also be the result of variations in the kitchen atmosphere. Verify incoming gas pressure in the same way as for “popping,” discussed in the preceding paragraphs. Variations in the kitchen atmosphere are usually caused by air conditioning and/or ventilation units starting and stopping during the day. As they start and stop, the pressure in the kitchen may change from positive or neutral to negative, or vice versa. They may also cause changes in airflow patterns that may affect flame intensity.
Flames “rolling” out of the fryer are usually an indication of negative pressure in the kitchen. Air is being sucked out of the fryer enclosure and the flames are literally following the air. If negative pressure is not the cause, check for high burner manifold gas pressure in accordance with the procedures in Chapter 5 of the Installation and Operation Manual (P/N
An excessively noisy burner, especially with flames visible above the flue opening, may indicate that the burner gas pressure is too high, or it may simply be that the gas valve vent tube is blocked. If the gas pressure is correct and the vent tube in unobstructed, the gas valve regulator is probably defective.