Have a State Water Heater model# PRV 50 PBRT0 L.P. Gas
Pilot light stays on maybe 1/2 to 1- hr then goes out! Everything I read leads to the
Thermo-couple .

First make sure the pilot orifice is clean since sometimes a slight restriction will lower the flame quality so the thermocouple will not get hot enough to generate electric to hold the safety of the valve open. If the pilot is OK then a thermocouple replacement is in order.

CAUTION: Whenever you are working on a propane appliance extra caution needs to be taken. Propane is unforgiving and pockets in areas unlike natural gas that disapates into the air. Propane if mishandeled can go BOOM much faster than Natural gas. In other words when you take apart the pilot assembly to clean the orifice be sure to tighten all gas connections correctly and use soap bubbles or a electronic gas sniffer to test for leaks.

Thank, HVAC1000, after watching further, pilot light stays on for complete cycle (heating the water) once the burner turns off, pilot light seems to go out as well

It seems to me that your water heater might be a power vent model but State does not have your heater listed on there web site at all under the number you posted for a model number. I will need all the numbers off the water heater information tag to check further.

The model number you provided is not listed at State water heater. I will need all the information off the model tag plate. ALL numbers letters etc.

HVAC1000, verified the model# PRV 50 PBRT0 Make: STATE Water Heater
50 Gallon / 40,000 BTU there is a ANS # IA 1991
SERIAL# C95246587
Since last posting things are changing, pilot light is staying on, but burner not kicking on ?
Thanks, denlyn

Sorry reconfirm your model not listed see list below. I need to address you model number to see which burner/ignition/safety system you have to give you proper info.

State Industries | Instruction Manuals, Residential Gas (http://www.statewaterheaters.com/lit/im/res-gas.html)

Are you in the USA?