VL SERIES STEAMER - SERVICE PROCEDURES AND ADJUSTMENTS
D.With the thermocouple disconnected, connect the meter leads to the tube and threaded end. Turn the power switch ON and light the pilot. Hold down the OFF/PILOT/ON knob and allow the pilot to heat the thermocouple for one to two minutes. Take an open circuit reading and compare with the chart below.
1)If the reading is less than the minimum or thermocouple is not operating as described, replace the thermocouple as outlined under
“PILOT AND THERMOCOUPLE ASSEMBLY (GAS MODELS)” in
“REMOVAL AND REPLACEMENT OF PARTS” then check for proper operation.
3.If after checking and/or replacing thermocouple, the pilot or main burners are still not functioning properly, then a problem in the gas combination control valve exists as well. Replace the combination control valve as outlined under “GAS COMBINATION CONTROL VALVE” in “REMOVAL AND REPLACEMENT OF PARTS” then check for proper operation.
NOTE: Gas combination control valves are not serviceable and should not be disassembled. Once you have isolated the problem to this control, replace it. Do not attempt to repair the assembly.
THERMOCOUPLE
DC MILLIVOLT
READINGS
| CLOSED CIRCUIT | OPEN CIRCUIT |
| (CONNECTED) | (DISCONNECTED) |
|
|
|
|
|
|
Typical | 15 |
|
|
|
|
Range | 10 - 20 | 20 - 35 |
GAS BURNERS
The main gas burners are located under the boiler for heating and number five to seven depending on the steamer model. They are made of aluminized steel with lanced type ports and have adjustable air shutters in the front. Fixed orifice type hoods extend from the manifold to establish gas flow to each burner.
Air Shutter Adjustment
1.Ignite the burners and allow to heat up for at least five minutes.
2.Verify the manifold pressure as outlined under
“GAS MANIFOLD PRESSURE ADJUSTMENT”.
3.Loosen the set screw on the burner being adjusted. Closing the air shutter will decrease primary air to the burner and opening the shutter will increase primary air the burner.
4.Monitor the burner flame and set the air shutter opening as follows:
A.Open up the air shutter until the inner portion (blue) of the flame lifts off the burner port and then turn the air shutter back until the flame touches the burner port again. A slight tinge of orange and yellow in the flame is acceptable. An extremely yellow flame indicates too little primary air (oxygen), producing poor burning characteristics and the heating efficiency drops off. A by product of this would be soot (carbon).
Factory air shutter settings are: natural gas - open approximately ½ inch; propane gas - fully open.
5.After the air shutter adjustment is made, tighten the set screw.
Inspection
Remove gas burners by lifting burner up and sliding it to the rear just enough to clear the gas orifice hood. Lower the front end of burner and bring it forward under the gas manifold pipe. Inspect burner for clogged or damaged ports. Clean or replace as necessary. When reinstalling burners, assure that locating pin is in the hole for proper positioning and to prevent burner from rolling over.
AUTOMATIC IGNITION SYSTEMS
(GAS MODELS)
When the main power switch is turned ON and the ignition control modules reset switch is in the ON position, the ignition control module is energized with 24VAC between terminals five and six.
High voltage is sent from terminal nine to the spark electrode and an output of 24 volts is sent from terminals two and three to the pilot coil in the combination valve, allowing gas to flow to the pilot. The sparking will continue for 90 seconds or until the flame sensor has confirmed that an adequate pilot flame is present.
Page 31 of 88
