MARSAL MB236 Service Manual Download Page 5

4

 

 

THERMOSTAT

 

CALIBRATION

 

1.

 

Attach pyrometer lead to thermostat bulb in the baking compartment. If a pyrometer is not 
available, place a reliable mercury type oven thermometer in the center of the baking deck 
(Approximately 1” above the surface).  

2.

 

Preheat the oven to at least 400° F (204° C). 

3.

 

When the burner reaches bypass or minimum flame, take the temperature reading.  

4.

 

If the temperature is within 10° F (6° C) of the thermostat setting, do not change the 
thermostat settings. 

5.

 

If the temperature differs more than 10° F (6° C) from the thermostat setting, adjust the 
thermostat as follows: 

A.

 

Pull thermostat dial straight off without turning. 

B.

 

Hold calibration plate on thermostat and loosen the two calibration lock screws 
until the plate can be moved without moving the control. 

C.

 

Turn calibration plate so that pyrometer reading is set in line with the indicator 
mark at the 12 o’clock temperature variation will be 50° F (28° C) between letters. 
Adjust the calibration plate as follows: 

1.

 

Turn calibration plate counterclockwise if pyrometer or thermometer 
reading is higher than the dial reading OR clockwise if the pyrometer or 
thermometer reading is lower than the dial reading. 

2.

 

Hold calibration plate and tighten two screws firmly. 

3.

 

Replace dial.  

 

 

Figure 3 

Summary of Contents for MB236

Page 1: ...k Ovens MB42 MB60 MB236 MB866 SD236 SD248 SD260 SD448 SD660 SD1048 SD1060 SD866 SD10866 WF42 WF60 RETAIN THIS MANUAL FOR FUTURE REFERENCE 2016 Marsal Pizza Ovens 175 E Hoffman Ave Lindenhurst NY 11757 631 226 6688 www marsalsons com ...

Page 2: ...e from pilot burner body 3 Clean orifice by blowing any foreign matter out the orifice hole Take care not to enlarge orifice hole 4 Replace components in reverse order If the pilot burner still does not operate or the main burner comes with a low flame 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 bal...

Page 3: ...ay be rectified by the adjustment of pilot burners main burners or thermostats It is therefore wise to attempt to correct operational difficulties through adjustment rather than the immediate replacement of parts PILOT BURNER ADJUSTMENT 70101 A commonly diagnosed malfunction of the safety pilot valve is the pilot burner flame sensing bulb relationship resulting from Improper draft Low gas pressure...

Page 4: ...hese flames will drop back to the port and lift again intermittently They are caused by too much primary air Decreasing the shutter opening will stop lifting flames o Floating flames are long and lazy in appearance poorly defined quiet flames which roll around the combustion chamber sometimes completely off the ports Floating flames result from too little secondary air Lack of secondary air is cau...

Page 5: ...he thermostat setting adjust the thermostat as follows A Pull thermostat dial straight off without turning B Hold calibration plate on thermostat and loosen the two calibration lock screws until the plate can be moved without moving the control C Turn calibration plate so that pyrometer reading is set in line with the indicator mark at the 12 o clock temperature variation will be 50 F 28 C between...

Page 6: ...pen combustion compartment door 2 Remove the burner door by removing its hinges 3 Remove the heat shields by removing the three screws that hold it together 4 Remove the screw that holds the pilot burner to the bracket 5 Remove the capillary bulb 6 Disconnect gas supply tubing from pilot burner 7 Replace pilot burner in reverse order from removal OVEN LIGHT BULB REMOVAL MB SERIES ONLY CAUTION Part...

Page 7: ... from removal AUTOMATIC SAFETY PILOT VALVE MAIN MANUAL CONTROL VALVE AND THERMOSTAT REMOVAL 1 Remove Control Stack Assembly see above 2 Remove respective control from Control Stack Assembly 3 Replace new control and other components in Control Stack Assembly in reverse order ATTENTION THE TSII SAFETY VALVE CAN BE REPLACED BY REPLACING THE HEAD ONLY LEAVING THE BODY STILL ATTACHED TO THE CONTROL ST...

Page 8: ...OT BURNER GOES OUT 1 Pilot thermocouple not in center of flame 2 Poor draft conditions snuff out flame no flue pipe 3 Too much draft pulls the flame away from thermocouple 4 Air from fans or register blowing at front of oven 5 Pilot flame too low 6 Pilot orifice is dirty 7 Thermocouple is defective 8 Safety pilot valve defective 9 Gas leak at pilot orifice fitting BURNER FAILS TO COME ON WHEN PILO...

Page 9: ...the oven 2 Oven temperature too low OVEN WILL NOT KEEP UP AT BUSY TIMES OR THERE IS UNEVEN COOKING 1 Gas pressure too low 2 Insufficient gas volume due to too small gas supply lines 3 Additional gas regulators installed 4 Poor draft conditions 5 Too much draft pulling heat out of the ovens 6 Air from fans or register blowing at front of oven SOOTING IN BAKING OR BURNER CHAMBER 1 Air shutter space ...

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