Re: water heater pressure relief
Posted by John Scates on February 02, 19101 at 19:36:46:
In response to Re: water heater pressure relief
Charlie is right. The leak most likely comes from water expansion, combined with a check-valve somewhere in your water supply. Recently, more and more communities are requiring check-valves to prevent water from homes back into the community water source. The relief valves are typically set to open at 150 psi or 210 degrees. Your heater is not immediately hitting the relief valve stem with 210 degrees, since it is immersed in relatively "cool" water, so temperature is not the cause of the immediate activation.

DO NOT attempt to relocate or modify the relief valve. Water heaters are pressure vessels and can reach dangerous pressures if the valve is rendered ineffective.

At this point, I see two solutions.
1. Install a drain pipe from the relief valve down into a sink. You do have a sink in your dark room, don't you?
2. Install a device to absorb the expanding water. If this is happening in your dark room, where you see it, it may also be happening at the primary water heater too. A device called an "expansion tank" is sold to eliminate the bleed-off from these relief valves in installations where check-valves are also present.

Hope this helps,
- John Scates

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