Hot Water Heater Questions - DIY Chatroom

matapus · 07-02-2009, 01:13 AM

Yesterday my wife noticed that the hot water was kinda rusty. This morning there was no hot water. The pilot was lit, and even when I turn the thermostat all the way up it still doesnt light. I opened up the drain valve to see if the rust was coming from the tank or possibly from an iron fitting somewhere. It came out at varying pressures and with rust varying along with the pressure changes. The cold water is fine by the way. I know because I had to take a very cold shower after work today. Any advice on this would be appricianted. Could it be the annode rod. If I have rust in the tank is it already too late. Am I doomed to cold showers forever?
Thanks for your advice
Matt

Thurman · 07-02-2009, 03:34 AM

To be honest, what I know about gas water heaters is very little. We do know this is a gas unit, but do not know it's age. But I do know this, if you turned the t'stat all the way up, and the burner did not light, then something is telling your control box that the water temp is high enough it does not need to be heated. This could be a thermocouple, or a bad control box. Then again if the unit will cycle by itself the system must be working. Now, you say you opened the "drain valve" and got varying pressures and with rust. It's important to know if you actually opened the tank drain valve which is located at the bottom of the tank, or the High Temperature & Pressure Safety Relief Valve which is usually located on top or high up on the side of a tank. If you opened the valve at the bottom of the tank and got varying pressures and rusty water, I'd say prepare for a replacement water heater. If you opened the T&P valve and got the varying pressure and rusty water, prepare for a new water heater and a leaky T&P valve, as the rust particulates will often make them start leaking once the enter them. You may buy some time with shutting the unit down, draining the tank and flushing it out with the incoming water to clean out some of the rust. PLEASE do an online search for how to properly do this if you do not already know. Good Luck, David

kenmac · 07-02-2009, 08:53 AM

Is it turned to the on position & not still in the pilot postion ??

AllanJ · 07-02-2009, 01:49 PM

Turn the little knob from "run" (or "on") to "pilot". (For electric heaters, shut off the power.)

Turn off the water heater cold inlet.

Open a hot water faucet or two upstairs.

Open the drain valve at the bottom of the water heater and let out a coupl'a bucketfuls of water. Actually better if you drain out enough until the water runs clear of rust.

When done, close the drain valve and turn the water back on.

Wait until water gushes from open hot water faucets upstairs before turning the heater back on.

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If you trip the pressure relief valve, usually at or near the top of the tank, there is a good chance that sediment and rust up there may re-arrange itself and prevent the valve from closing again. Also you will not get as much rust out that way.

The anode rod probably has nothing to do with all this. The anode rod really should be inspected every few years and replaced if it has rusted off or broken off. If you wait too long you might be unable to unscrew it without making the whole tank turn and snap off the water and gas pipes!

adpanko · 07-02-2009, 02:55 PM

I'd say that if you that much rust in the tank that it visible comes out when you drain it, you might as well replace the tank because it is rusting out from the inside and will eventually rust through and leak. How old is the tank? Getting 10 years from a hot water tank is respectable. 15 or so years is darn good. Longer than that...you're on borrowed time.

Even if the annode rode isn't doing its thing, replacing it will only buy you some time at best, not correct the problem. You already have rusting inside, which won't go away with a new annode rod, and will only continue to worsen.

darsunt · 07-02-2009, 05:24 PM

I've drained some old water heaters and I've never seen a lot of rust, so I would be very concerned.

It is odd the tank stops heating water when the rust appears. Possibly the hot water was doing something to prevent rust from escaping, and a failure of the thermostat allowed the rust to come out. Otherwise it is a puzzle because I don't think rust or sediment in a tank can effect the ability of the water heater to turn on or off, it just makes it less efficient.

Anyways, better the tank fail cold than to fail too hot.