Hello,

I'm trying to flush a very new AO Smith gas heater water. See photo:

[imgur.com]

I have put the device to "pilot". I have connected a garden hose to the tank's drain valve at the bottom of the tank. I have closed the cold-water inlet to the tank. I have opened a nearby hot-water faucet. But nothing flushes out.

If I re-open the cold-water inlet, water starts to flush. It's initially hot then becomes cold but not that cold.

I'm confused by the pressure valve and what I'm supposed to do with it while trying to flush the tank. Is there a clear image or video explanation somewhere?

[imgur.com]

Thanks in advance.

You are describing a 'drain' procedure. To 'flush', simply attach a hose to the drain valve, open the drain valve, and allow water to flush thru the heater and out to waste.

Your tank is probably full of sediment and it is clogging the drain; the pressure from the cold water is helping to push out the sediment. continue to flush it under pressure and keep a screwdriver handy to work the drain open and closed to dislodge any chunks if the water sounds like it isn't washing out the drain like it should. I replace the drains in my own water tanks to galvanized pipe with brass ball valves that are full port so that nothing can get stuck, but most people don't go to that trouble or even drain the tanks like they should.