Leaky Hot Water Heater

[ptranfa]

Our hot water heater is leaking. There is like a little spout on the botton that looks like you could attach a hose or something to and the water is leaking out of it rather heavily. This image is not my heater, I'm at work, but I can take a picture of my heater later. The area in red is around where the spout is. What can I do to stop the leak?

[LazyPup]

Not to worry, this is a very common problem which even in a worst case scenario can be easily fixed for less than $10.

The valve you are describing is properly called a "Boiler Drain Cock" and it's intended purpose is to permit draining or flushing the water heater storage storage vessel.

Back in the late 1980's I lived about 6 blocks from one of the major water heater manufacturers home offices and on many occassions I would sit in the local coffee shop and talk to some of their chief designers. One day I happened to ask one of the guys, "why in heavens name would you design a space age quality high tech water heater then fit it with the cheapest junk box plastic drain valve that you could find?" To my utter amazement their answer made good sense. Technically speaking, the plastic valves have a much lower coefficient of heat transfer than does thier brass counterparts, therefore the use of the plastic valves will reduce the operational energy cost of the water heater by an average of $2 per year.

Well, so much for the technically perfect world of theoretical science, here in the real world those valves are still little more than junk. In reality they work fine if you never attempt to open them, but if you happen to open that valve to flush the tank in the manner that the manufacturers recommend annually, the odds are at best 50/50 that it will not properly seal again. Normally when installing a new water heater I explain this to the customer and give them the option of having the plastic valve removed and installing a brass valve for the actual cost of the valve which is about $4.

Having said all of that, let us get down to the problem at hand.

You may have some success by simply tightening the valve handle a bit.

If tightening the valve handle did not resolve the problem you should begin by locating the cold water supply valve on the top of the water heater and turn it off, then place a container under the drain valve and open it momentarily, then close it again. You may need to repeat this process a couple times. Hopefully this will flush away any scale or debris that may be caught on the mating surfaces of the valve. Do not forget to reopen the cold water supply valve when you finish this step.

If these techniques have not resolved your problem you will need to replace the valve.

Before you begin you will need a new "3/4inch MIP Boiler Drain Valve" (This is a boiler drain valve that has a 3/4" male pipe thread mount)

In order to change the valve you will first need to drain the tank.

Begin by turning the water heater off, either by closing the gas supply valve or in the case of an electric heater you pull the service disconnect or switch the circuit breaker off. (This is very imporant because operating a water heater burner or electrical elements for even a few moments when the tank is empty can cause serious damage to the water heater.)

Connect a garden hose to the drain valve and run it to a floor drain or outdoors then open the drain valve.

When the hose is filled and is flowing to the drain turn the cold water supply valve off, then open a hot water faucett somewhere in the house to permit air to vent into the hot water distribution lines. This will aid in the draining process.

When the tank is drained you can simply unscrew the valve from the water heater vessel with a small pipe wrench.

Apply a bit of thread dope to the threads of your new "boiler drain cock" and screw it into the water heater tightly.

Make sure the drain valve is closed tight, then open the cold water supply valve to refill the water heater and hot water pipes. During the filling operation the excess air in the tank and pipes will vent out through the hot water faucett that you previously opened. You may expect to see a bit of spitting and sputtering from that faucett as the air is expelled and the lines refill. Once you have full flow you may turn that faucett off. You should then open each hot water faucett in the house to make sure the excess air is bled out of the branch lines.

Once you have the system refilled you can then turn the electrical service or gas supply on and light the pilot light and you problem will be resolved.

NOTE: if you happen to have a new high efficiency water heater the insulation may be too thick to permit installing a standard boiler drain cock. While they are difficult to find in the local hardware or home supply stores they do make a long shank boiler drain cock for this application which can be obtained at a local Plumbing Supply house, or you could get a "3/4"xClose" pipe nipple and a coupling. Apply thread joint compound to the threads of the pipe nipple and screw on end into the water heater and screw the coupling on the other end and tighten it snugly in place with your pipe wrench. This will then leave an open female thread on the end of the nipple where you can screw a standard boiler drain in.

[Dennis_Alaska]

Our water heater dripped for about 8 months, filling a 2-gallon bucket every 2 days. I'd been to Lowes to get a new drain cock -- was told I had to order one from the manufacturer, and that I'd need the exact model number and year it was purchased.

After I read this fix, I picked up a brass drain cock, cost $4.80, drained the heater, put in the new valve, and it's fixed. EXCELLENT.

Just wanted to say thanks, and you saved me from calling a plumber or having to go the time/expense of replacing the water heater.

[Phelps]

I've had similar leaks in rentals, and I merely buy brass female hose thread cap covers that come with the rubber washer, and screw it on.