I just woke up to find the pressure valve on our water heater shooting out cold water ( not hot - it may have flooded out the natural gas burner at the bottom ) and flooding the house. ( someone removed the vertical pipe from the bottom of it, if it had one, so it was flooding outside of the bottom drain pan ) It may have been doing this for 90 minutes since I got up before to use the bathroom - the last time I was up and it wasn't doing it. I shut the water off and called the water company and they say it's not overpressure from them. ( though the pressure here sometimes goes to 90 PSI normally )
We do have a problem when the whole house humidifier runs sometimes. It can take a trickle of hot water from the water heater and cause the temp to go up quite a bit, but it hasn't caused the pressure valve to go off like this.
What's the likely cause of this? Do I need a plumber or should I just try and replace the valve myself?