Water Heaters - Gushing pressure relief valve!

Recently I turned on the hot water tap and very hot water and air came spurting out of the tap. I went down to the basement and hot water was gushing out of the pressure relief valve and onto the floor and had obviously been doing so for a while - my unfinished basement was like a steam bath! I turned the WH off at the electrical panel and let it drain. I have an oil-fired water heater. Would the problem most likely be the thermostat or the pressure relief valve? Would the WH need to be replaced or is it something that could possibly be repaired? (I don't have the money for either?!) Would I be able to repair it myself? (fairly handy but not professionally trained) And last but not least... would it pose a danger to turn it on at the panel for short periods of time to heat water for quick showers? I would appreciate any advice on this very much! Thanks!

The correct thermostat for that heater would have 2 thermostats in one box. The primary one would be the one you adjust for the temp you want at the faucets. The second one is pre-set at about 180 degrees. It sounds like the thermostat replacement would be the first thing to do. It is probably the least complicated of any service you may have to do on that unit. I would recommend that you get the exact same thermostat that is on there now so it matches the well (the part that the thermostat goes into) in the tank. Post back if you have questions. It would not be a horrible thing to do to turn the unit on periodically to get hot water. The safety valve obviously is functioning properly so that protects you if you leave it on too long. DO NOT leave it on unattended. Now that you know something is wrong with it, you would be risking a major catastrophe.

Ken