13 year old pitco frialator fryer pilot wont stay on. changed gas valve and thermopile.... pilot light wont stay lite

Hi there.
Try cleaning the thermopile, it must be free of soot or any form of dirt. Ensure that the gas pressure is sufficient, all wiring connections are tight and the hi limit is good.
If all of these are okay and the pilot still wont stay lit, try replacing the thermopile.
For Owner's manual download that will help you in minor fryer troubleshooting and reference, visit http://www.pitco.com
Regards.

Check the gas pressure, it must meet the standard gas pressure written on the nameplate. Check also the quality of pilot flame, poor pilot flame quality will not properly heat up the thermopile which in turn will result in poor fryer operation.

Try to clean the thermopile, it should be free of dirt/ soot so heat from pilot flame could be sensed better. Thermopiles generate small amount of voltage when heated properly, the voltage it creates is used in energizing gas valve solenoid coils.
Check also if the hi limit is good, small amount of voltage thermopile generates pass through hi limit terminals.

Try first to clean the thermopile. If it has accumulated soot/ carbon, it will not sense enough heat from the pilot flame to generate small amount of electricity to energize the pilot valve and main valve of gas valve.

Check if the the gas pressure is sufficient (as stated on unit's nameplate). Check if the hi limit device is good. Check also if the thermopile (cylindrical metal with two wires standing behind the pilot hood) is receiving enough heat from the pilot flame. The voltage generated by thermopile should be 500millivolts in order to open pilot and main valve. If there is 500millivolt on gas valve thermopile and the pilot flame does not stay lit, you have to replace the gas valve. If the thermopile is glowing red and the voltage generated does not reach 500 millivots, you have to replace the thermopile.

You have to check the following:
1. Does the pilot flame has the ability to heat up the thermopile? Themopile must be properly heated in order to generate voltage to open the pilot valve as well as main valve.
2. When the thermolpile is heated, does it generates 500 millivolts? If not, your thermopile needs replacement. If it does and still the pilot flame wont stay lit, your gas valve needs replacement.
3. Does the hi limit device has continuity on its terminals? If there is no continuity on hi limit terminals, you have to replace it. One of the thermopile wire passes on this hi limit terminal to cut the voltage supply on pilot valve in case the oil temperature reaches 450F.
4. Check and tighten all wiring connections, millivolts generated by thermopile will not pass on loosely terminated wiring.

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.

Check if the flame quality of the pilot is good. Small amount of voltage generated by thermopile used in energizing pilot main valve coil during fryer operation relies on the quality of pilot flame, also, the thermopile itself should be free of soot or any form of dirt in order for it to absorb the heat from pilot flame.
Check also the gas pressure, it should meet the gas pressure required on the nameplate.

Make sure that the gas pressure is standard (as rated on nameplate), thermopile must be clean (no dirt or soot) and the thermostat is good.

if you changed the thermopile and still have the same problem make sure that the sensing bulb is directly over the flame. If it is and the thermopile is installed correctly the next thing would be the gas valve.

Hope this helps