GAS OVEN SERVICE MANUAL
MODELS: MB42, MB60, MB236, MB260, MB866,
SD236, SD248, SD260, SD448, SD660, SD1048, SD1060, SD866, SD10866, WF42, WF60
©2018 Marsal 42 Allen Martin Drive, Essex Junction, VT 05452 (802) 658-6600 www.marsalsons.com
P/N 72613 Rev A (1/18)
TABLE OF CONTENTS
I TESTING OF COMPONENTS
AUTOMATIC SAFETY PILOT VALVE TSII #55127 ....................................................... 3
MAIN MANUAL CONTROL VALVE #70380 .............................................................. 3
THERMOSTAT FDTH #71880 ........................................................................... 3
II MAINTENANCE INSTRUCTIONS
ADJUSTMENTS ......................................................................................... 4
PILOT BURNER ADJUSTMENT #70101 .............................................................. 4
MAIN BURNER ADJUSTMENTS ..................................................................... 4
BYPASS MINIMUM BURNER FLAME ADJUSTMENTS .............................................. 5
THERMOSTAT CALIBRATION ....................................................................... 5
PARTS REMOVAL & REPLACEMENT .................................................................... 6
MAIN BURNER REMOVAL .......................................................................... 6
PILOT BURNER REMOVAL: #70101 ................................................................. 6
OVEN LIGHT BULB REMOVAL MB SERIES ONLY................................................... 7
GAS CONTROL AND PIPING CONTROL STACK ASSEMBLY REMOVAL .............................. 7
AUTOMATIC SAFETY PILOT VALVE, MAIN MANUAL CONTROL VALVE,
AND THERMOSTAT REMOVAL ...................................................................... 7
PRESSURE REGULATOR REPLACEMENT #71881 N OR #71882 P ................................ 8
III TROUBLESHOOTING .......................................................................... 8
GAS DECK OVEN SERVICE MANUAL 2
TESTING OF COMPONENTS
AUTOMATIC SAFETY PILOT VALVE (TSII) #55127
Pilot gas is supplied from the main valve inlet through a drilled passageway to the pilot burner. Pushing
the red reset button temporarily allows gas to ow to the pilot burner for ignition of the pilot burner ame.
When the bulb heats up, the main valve opens to allow gas to ow to the main burner. The red reset button
is then released.
If the pilot burner ame fails and cannot be reactivated the following
test can be performed:
• Pilot burner adjustment: Refer to following page.
• Clean Pilot burner’s limiting orice as follows:
a. Disconnect gas tubing at the pilot burner body
b. Remove cup shaped orice from pilot burner body
c. Clean orice by blowing any foreign matter out the orice
hole. Take care not to enlarge orice hole.
d. Replace components in reverse order. If the pilot burner still
does not operate or the main burner comes with a low ame,
or will not come at all, replace the Automatic Safety Pilot Valve
(TSII)
MAIN MANUAL CONTROL VALVE #70380
The main manual control valve is a simple ball valve. Due to its simplicity, failures of this type of valve are practically non-existent. For
diculties associated with this control, it would be best to replace
the valve.
THERMOSTAT FDTH #71880
For any suspected thermostat problems the following procedures
should be reviewed in this manual:
• Thermostat adjustment
• Bypass (Minimum Burner Flame) adjustment.
Figure 1
• Thermostat calibration. Most thermostat failures will generally fall into one of the following three categories:
1. If thermostat is in a runaway condition and will not shut o at set temperature, replace the thermostat.
2. If thermostat will not maintain calibration after adjustment, replace thermostat.
3. If thermostat bulb or capillary are cut, bent, or unnecessarily attened, replace thermostat. (This is NOT
covered under the warranty!)
3 GAS DECK OVEN SERVICE MANUAL