Replacing drain valve that is clogged

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jag_man653

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I have a Whirlpool water heater model 40T12-40UNG about 7 years old. When I open the drain valve there's barely a dribble. Is this because I've not opened it far enough? Dare I keep turning? Or, perhaps it's because I've neglected to flush it regularly and it's blocked by a mountain of sediment?

BTW, there's a plastic "collar" around it that I'm thinking is a "lock nut." Is that right?

drainvalve_edited.jpg
 

Tuttles Revenge

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Hmm... I seem to think they got rid of plastic drain valves over a decade ago, I havent been seeing them on tanks that we're replacing nowdays. But in any case I never touch plastic drain valves anymore. I've heard of people replacing them and if I were you, I would be ready to replace that valve if it snaps off. And at the very least a hose threaded cap when that valve fails to shut off.

If I were going to try to drain that tank I first would be doing it under pressure. Water heater supply water off first, open drain valve, then use your supply valve to pressure water out of the drain via a hose. If that doesn't work, water valve off, T&P open and hook up a hose spigot to the drain to force water pressure backwards through the drain.
 

jag_man653

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Hmm... I seem to think they got rid of plastic drain valves over a decade ago, I havent been seeing them on tanks that we're replacing nowdays. But in any case I never touch plastic drain valves anymore. I've heard of people replacing them and if I were you, I would be ready to replace that valve if it snaps off. And at the very least a hose threaded cap when that valve fails to shut off.

If I were going to try to drain that tank I first would be doing it under pressure. Water heater supply water off first, open drain valve, then use your supply valve to pressure water out of the drain via a hose. If that doesn't work, water valve off, T&P open and hook up a hose spigot to the drain to force water pressure backwards through the drain.
Ugh... not what I wanted to hear.
Not sure what you mean "then use your supply valve to pressure water out of the drain via a hose." Isn't the supply valve in the cold water line above the tank? In my case that would be up in the attic since the house was replumbed through the attic after a slab leak years ago. So do you mean just open that valve again the instruction said to close before opening the drain valve? I do see the logic to that though, i.e. it would be a lot more pressure at the drain valve. Just want to be clear.

Also, are you saying the plastic valve could shear off, leaving the threaded portion in the tank? That would be a nightmare!

BTW, I'd call a plumber but just a couple weeks ago I had a toilet replaced to the tune of $370, not counting the toilet which I provided. Easy access too.

Thanks for your help.
 

jag_man653

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Success! With the tank inlet open and no hot water faucets I opened the drain valve through a 10' garden hose. After the hose filled the water flowed out smartly. I directed it into a blue bucket and could see tiny white particles collecting. I closed the drain valve after about 2 gallons and closed the drain valve. No leakage! So, the drain valve is OK.

Next, I'll do a "full flush." With the gas turned off I'll let the tank fill completely, and then with supply water off and a hot water faucet open, I'll drain the tank completely. Hopefully, I'll have a clean tank!
 

Fitter30

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Opening a faucet won't drain the tank for a flush. Has to be done thru the drain valve. After flushing tank the aerators at faucets might need to to be cleaned after a few days.
 

jag_man653

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Opening a faucet won't drain the tank for a flush. Has to be done thru the drain valve. After flushing tank the aerators at faucets might need to to be cleaned after a few days.
Of course it won't. I will indeed open the drain valve. The open hot water faucet will allow air to enter while water exits at the drain valve. I've watched YouTube videos showing this procedure. Or am I missing something?
 

Tuttles Revenge

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Good, you may have knocked something loose when you opened and closed it the first time.
 

Skeezix

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I had the same problem. Plastic valve that would only dribble when I opened it. Poked a rod up the spout and it dribbled a bit more. Opened the T&P valve - no help.

So I removed the plastic valve and in its place I installed a brass quarter-turn ball valve. Now when I open this new quarter-turn valve and then open the T&P valve I get full flow. Problem solved!
 
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