[hcoles]

Originally Posted by ossiblue

Well, I'm no expert but this is how I do it (but to be honest, haven't done it recently and my heater is waaay past it's life expectancy.)

1. Turn off the cold inlet and hot outlet. Turn the gas valve to OFF.

2. Connect hose to drain. Open drain petcock.

3. Flip up safety valve lever to allow air to enter tank. Alternately, you can disconnect the hot water flex hose from the tank.

4. Once all water has drained out, turn on the cold water and flush as much sediment from the bottom as possible. Flush is short intervals as you don't want to fill the tank too much beyond the bottom level. Look for clear water from the hose.

5. Close petcock and remove hose.

6. If you disconnected the hot water outlet, reconnect it, but be sure the safety valve is opened. Do not open the hot water outlet valve, yet.

7. Slowly, open the cold water valve and allow the water to fill the tank. Gradually open the valve until it's fully opened.

8. Listen for air escaping from the safety valve.

9. When water emerges from the safety valve, close it.

10. Let the heater sit for a period of time to allow settling of any sediment. Meanwhile, find the closest hot water faucet to the heater.

11. After wait period, open closest hot faucet, open the hot water valve at the heater, and monitor for escaping air. Close faucet when water flows freely.

12. Open gas valve and relight heater, if necessary.

Looks complicated, but it's not. Not a perfect method, but tends to minimize suspended debris.

Thanks LJ - I'll give it a go and see what happens.