Rheem model 41vrp40n power vent water heater won't even light the pilot. code flashes 4 times and says ''pres sw open'' for this code .what does this mean? what do i do to fix this?

How to relight water heater pilot light

http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent

gene

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Error code means that you have electronic gas control valve.

Copy following link to identify gas control valve, read error code meanings for each, and download service manual relevant to each gas control, but not specifically Rheem since rheem does not post service manuals.
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent

The fact that water heater restarts, means that water heater is getting gas, getting sufficient air for combustion, thermister is ok, gas pressure is good, etc.
The fact that you unplug and replug water heater and it works, shows that you have power vent model.
Since water heater worked correctly before, 2 flashes with Rheem power vent model could mean that pressure switch has failed.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

If pilot lights and flame is robust and clear blue, and pilot goes out later, then some suspects can be excluded: air in gas line, low gas pressure, thermocouple is overtightened (finger-tight + 1/4 turn), thermocouple not positioned correctly in the flame, dirty pilot tube.
If flame is yellowish and small: then clean pilot tube and combustion parts.
http://waterheatertimer.org/How-to-install-gas-water-heater.html#clean
Remaining suspects can include: air in gas line, low gas pressure, bad gas control valve, tight house so household vent fans pull air down water heater vent that blows out pilot, hot attic with inadequate ventilation, water dripping down vent.

Open following links to read troubleshoot resources.
http://waterheatertimer.org/pdf/Pilot-light-will-not-stay-lit.pdf
http://waterheatertimer.org/How-to-install-gas-water-heater.html#troubleshoot

Open following links for pilot light help:
http://waterheatertimer.org/How-to-install-gas-water-heater.html#troubleshoot
http://waterheatertimer.org/pdf/Pilot-light-will-not-stay-lit.pdf
http://waterheatertimer.org/images/Negative-pressure.jpg
http://waterheatertimer.org/pdf/Bosch_Ventilating_tight_houses.pdf

Since pilot light goes out and can be re-lit, problem is probably not thermocouple, gas control valve, or air in gas line. But these things can factor in as contributing factors.
Problem is likely one of following or combination of following including dirty burner parts, tight house, incorrect vent lengths, negative pressure caused by other venting appliances, condensation dripping down into combustion area, and inadequate oxygen supply due to hot or closed-off room or attic location.

Gas water heaters draw air from surrounding area. If water heater is located inside house, then air has to enter home through cracks and when doors and windows are opened. Other gas appliances and vent fans also draw air from same indoor area. When other vent fans turn on, air can be drawn down the water heater vent and blow out pilot light.
Inspect combustion chamber to make sure there is no condensate water dripping down from incorrect vent that is putting out flame. If combustion chamber is dry, then close doors and windows. Turn on all vent fans and gas appliances that vent outdoors, and see if water heater pilot goes out.
Consult with plumber or product manual about proper horizontal and vertical lengths of vent pipe for your model. Have plumber clean combustion parts and inspect vent termination and check gas pressure and bleed gas line.
Add louver opening to outdoors so air can enter room where water heater is located.

Problem can be bad gas control valve, bad wire connections, combustion chamber and burner parts need cleaning, bad venting, air in gas line. Rheem manual recommends calling service technician.
Open following link for gas water heater troubleshooting resources and illustrations for cleaning:
http://waterheatertimer.org/How-to-install-gas-water-heater.html#troubleshoot
http://waterheatertimer.org/pdf/How-to-clean-combustion-chamber.pdf
Generic pilot light information:
http://waterheatertimer.org/pdf/Pilot-light-will-not-stay-lit.pdf

Open following link for Rheem gas water heaters to identify product and download manual:
Click on link next to image, next page opens, click on Spec/Docs to find typical use and care manuals and then read troubleshooting tips for your specific unit where it suggests calling service technician.
http://www.rheem.com/Products/tank_water_heaters/gas_water_heaters

it may be the thermal coupling that is bad for the pilot light. if it goes bad the flame will go out. replace thermal coupling. so if the pilot light is out then it will not heat water. or turn burner on.

clean out gas chamber with vacuum. Also probably motherboard and rheem will send you another one.

The flashing light is a trouble sequence light. Find your manual to see what 4 flashes means. It's usually attached to the side of the water heater tank. Try a quick fix by unplugging the power vent and see what happens.

1. Turn off power vent blower and set water heater temp to vacation (lowest temp)
2. Turn on power vent blower
3. Turn the water heater temp from vacation (lowest temp) to hot (highest temp) four times.
4. Set the water heater temp to normal