Would Pitco 35C+ still heat if bulb/capillary of control thermostat breaks?

Normal fryers operate in the range 350-375?F. Safety cut-outs (also called "limit" or "overheat" thermostats) operate at 400?F or so. This can also occur if the oil level in the fryer is too low. If they operate, they normally require resetting with a tool, such as a screwdriver to push a reset button. If you mean that your control thermostat is set to 350?F and the safety cut out is cutting the power, then you probably have a faulty or damaged control thermostat. Commonly, the sensor bulb or the thin metal capillary are accidentally damaged by contact with metal utensils. In such cases, the thermostat mechanism has no pressure input to open the contacts, so the oil temperature rises until the safety cut out operates. The solution is to replace the entire control thermostat in such cases. Less commonly, it is also possible that the limit thermostat is faulty and is opening prematurely. I recommend that you monitor the oil temperature using a fryer thermometer when heating from cold. Place the thermometer bulb in the centre of the fryer or near to the thermostat bulb if you can see it. If the thermometer reads 350F when the limit 'stat clicks open, you need to replace the limit 'stat. (Some are adjustable, but this should only be attempted by a service engineer.) If the limit 'stat operates at 400?F approx., then your control 'stat needs replacing. You do not specify which model of Pitco fryer you have, so I cannot offer more specific advice. Do not attempt to replace the thermostat unless you know and follow all the safety and maintenance procedures.

it may not be the expansion valve. when they fail it usually loses charge in the bulb capillary. lack of heat should be reversing valve or control issue

Soot is formed when fuel combustion is incomplete. Check if the gas pressure is sufficient and of correct type (natural or propane gas). Thermostat can be checked by observing if the burner flame goes off when the oil temperature reached the thermostat setting. Price can be checked at pitco website on www.middleby.com.

you an fabricate a lid and it must be made of stainless steel. try to fabricate a lid with food grade silicone gasket that will fit on the fry tank opening so that oil will not spill if your truck is in transit.

Check the thermopile, it should be free of soot or any form of dirt. Pilot flame quality must be good. Gas pressure should meet the requirement as stated on the nameplate.

Hi there.
You may need to check the calibration of your fryer in to verify if the thermostat regulates the oil temperature as set on its dial. As for the thermostat body, it should be mounted properly to avoid movement that which could break the capillary.
You can download Pitco Fryer Owner's Manual which includes calibration procedure at http://www.pitco.com
Regards.

If the mechanical thermostat is set at temperature higher than the present oil temperature and does not "click" it is a bad thermostat and needs replacement. Clicking sound on thermostat indicates closing of the mechanical contacts.
Physically examine the thermostat capillary and sensing bulb, any puncture found indicates that it needs replacement.

Try to spray wd40 on knob.
If spraying wd40 doesn't work, you have to replace the gas valve.

Remove the burners and clean the burner orfices and baffles,also check the vent cap on the pressure regulator that sits on the back of the fryer.Let me know.

Replacing the t'stat can be hard. I would first evaluate the cost of the vat. Do you have any leaks now in it? I would replace the t'stats. The cost is much less than the cost of even a used one.