Water heater not draining

[Joe Landau]

AO Smith heater, 5 years old, had never been drained. So far: I closed the cold water feed to the heater. With a nearby hot water tap open, I get only a very small volume at the drain outlet, perhaps a cup in a minute. More like a leak than a drain. When I open the cold water feed hoping it will unclog the drain, I get full volume at the drain outlet. I have let that run for 15 minutes, but that does not change anything. Any suggestions? Thanks.

 

[Twowaxhack]

Open the relief valve while the drain is open. It’s air locked.

 

[Joe Landau]

Is that the T&P relief valve that I should open? I do have the hot water tap at the laundry sink open.

 

[Twowaxhack]

Is that the T&P relief valve that I should open? I do have the hot water tap at the laundry sink open.

YES, and as you see opening a faucet does nothing.

 

[wpns]

Or try opening the highest hot water valve in the house. In my experience, opening the TP relief valve can cause seating problems, so have a spare on hand in case it leaks

 

[Twowaxhack]

Or try opening the highest hot water valve in the house. In my experience, opening the TP relief valve can cause seating problems, so have a spare on hand in case it leaks

That won’t work.


If the valve won’t seat back then it needs to be replaced.

 

[wpns]

That won’t work.

Because?

 

[Twowaxhack]

Because?

Because it won’t give the tank air.

 

[havasu]

After I shut off my incoming cold water line, I open my kitchen hot water and that creates the air necessary to drain down my water heater. I often will purge off a few gallons and while doing so, I set my gas thermostat gown to vacation.

 

[Twowaxhack]

After I shut off my incoming cold water line, I open my kitchen hot water and that creates the air necessary to drain down my water heater. I often will purge off a few gallons and while doing so, I set my gas thermostat gown to vacation.

What size heater do you have and where is it located ? How old is it ?

Most heaters have heat traps and most heaters are taller than the lowest hot outlet unless the heaters in a basement.

 

[havasu]

Mine is a 50 gallon gas, and about 35 feet away from the water heater in an enclosure outside. it seems to have no issue sucking down using the hot water valve in the kitchen sink. I too will not jeopardize flipping the TPR valve.

 

[Twowaxhack]

Mine is a 50 gallon gas, and about 35 feet away from the water heater. it seems to have no issue sucking down using the hot water valve in the kitchen sink. I too will not jeopardize flipping the TPR valve.

Explain to me how the water heater can siphon when the top of the water heater is higher than your kitchen sink spout.

Are your water pipes to the kitchen sink in the ceiling or attic?

Flipping the T&P insures it works when it needs to.

 

[BlueSkyHigh]

I too will not jeopardize flipping the TPR valve.

Sage advice IMHO. After flipping mine to do a water heater flush it took about three days to finally seal completely. I got lucky.

Something I didn't realize was that, rather than drain and flush the tank by turning the water off and venting the tank (by whatever method floats your boat) and letting gravity do the work, I also was told by the MFR that the best way to flush it was to keep the inlet valve turned on and power flush through the drain port until the water ran clear. Does that make sense?

 

[sarg]

Just to mention a few points.
I open the T&P valve at the top of our electric heater when we drain the tank .... that's twice a year with no issues.
If your heater still has the factory compression type drain valve .... "flushing" anything of any size is futile .... Just doesn't make common sense to think it would.
As I've mentioned in other posts our system creates lots of sediment and the only effective method I've found is removing the bottom element and vacuuming out the sediment with a wet vac with some automotive heater hose attached. And also mention they make 3/4 ball valves made for flushing.

 

[BlueSkyHigh]

That's a nice drain valve. My current AO Smith has a quarter turn valve with a relatively nice sized hole. When doing a "gravity flush" the orifice got plugged so I had to re-pressurize the tank and power out the blockage.

 

[sarg]

In our case the biggest benefit of the 3/4 valve is the actual drain time is drastically reduced.

 

[RS]

Sage advice IMHO. After flipping mine to do a water heater flush it took about three days to finally seal completely. I got lucky.

Something I didn't realize was that, rather than drain and flush the tank by turning the water off and venting the tank (by whatever method floats your boat) and letting gravity do the work, I also was told by the MFR that the best way to flush it was to keep the inlet valve turned on and power flush through the drain port until the water ran clear. Does that make sense?

Yes it does! I drain 2 of them yearly because they are seasonal in a cold climate, but I use air pressure. We have wells at both places, so I pressurize the well pressure thank to about 60 psi, and the air pressure going down the dip tube agitates any sediment and I think the heater ends up being very clean inside. This has worked for us for many years, but we have water softeners so the water quality is pretty good.

 

[Twowaxhack]

How many relief valves have you guys flipped and nothing comes out ?

And then you you remove it, it’s totally packed with sediment and minerals ?

What does that valve do exactly ?

Happy Friday !

 

[BlueSkyHigh]

How many relief valves have you guys flipped and nothing comes out ?

And then you you remove it, it’s totally packed with sediment and minerals ?

What does that valve do exactly ?

Happy Friday !

TGIF indeed! The valve that was blocked for me was the drain valve at the bottom and not the T&P relief valve. I am behind the power curve because I failed to do what a man needs to do on his anniversary!

 

[havasu]

Regarding my drain down. If you think about it, if you open the TPR valve to release the suction, theoretically, only air should pass through the seals, so you should not have any contamination when the TPR valve seals up. Regardless, I've purchased them way too many times in the past, and just don't want to deal with those constant drips anymore. My hot water line leading to the kitchen sink is below slab, to my manifold, where that line to the hot water goes overhead, in my attic about 50 feet and out to my ground level water heater in the enclosure outside. Since my tank is 5 years old, I completed my first 1/2 drain down just 6 months ago, and was very surprised at all the pieces of stuff, which had the consistency of tapioca balls and blue flakes that covered my patio. Seeing how much crap I got out, I will try to do this annually to extend the life of my A.O Smith water heater.