Water Heaters - Electric Hot Water Heater Valves Pops Opens By itself?

I have been living in a rented home for 3 years. This being my third winter. I noticed that the kitchen sink water pressure was low and that there was no hot water. After a walk to the basement in 4 inches of water I noticed the pressure release valve on top of the hot water heater was open in the UP position. I simply shut it off by lowering it and within 15 minutes I had hot water in the house. It would be great if anyone can tell me why suddenly the valve made up it's mind to open today? After I get some replies you can tell me how dumb it is that I duct taped the valve in the OFF (middle) position to hopefully keep it from popping up on it's own again. Yes I do have renters insurance. :rolleyes: Has anyone EVER had a overflow valve open in the upward position? Is this even a overflow valve? Description is a brass valve that releases water from the hot water heater when the lever is lifted or pushed down and held. This is not a old Hot Water Heater. Thank you in advance for any help that anyone can provide.

Roadjungle, Welcome to the DIY Forums.
The valve is a temperature/pressure relief valve. It SHOULD only open when the temp or pressure in the water heater goes over the setting on the valve. You can find that info on the valve. It is commonly called a SAFETY valve because it keeps the tank from blowing up should temp or pressure get too high. I would remove the tape. Although it is a subject that I have not read up on, the valve may still open with the handle taped due to the fact that the handle pulls the seal up when you raise it but has a spring inside. I would not recommend waiting to find out. Check the temp setting on the water heater. It should be at mid-range.(120 degrees) Keep an eye on the WH and you may want to replace the T/P valve. Good luck.

Have the landlord replace the T&P valve. Taping it shut is not a good idea. It won't matter anyway as the it will still open itself to relief pressure, as Majak stated.

Now you need to find out why it opened itself. These will develop weakened springs after several years. So, you may have had a pressure surge in your water system or something may be going wrong with your water heater. Have your landlord hire someone qualified to work on this.

Good luck with your water heater....

It has been 10 days since the problem and it has not recurred. The landlord was notified and 1 day has now turned into 10. This is something I am more then capable of changing but until then everything is off the ground. Again thank you so much for your responses.