Draining hot water tank

[and3008]

Thought this would be an easy task...not so much. Tank won't drain - I can feel the hot water in the hose about 10 feet out then it doesn't feel hot. If I open the water inlet valve, it drains fine. I backflushed it with a washing machine hose, still not draining. Hooked the short washing machine hose and turned on the water inlet and the water runs clear. By the way, I was flushing it because it was making knocking noises. I did open the kitchen hot water faucet and tripped the pressure relief valve (which now leaks). My next step is a sticking a wire hanger in the valve.

What I don't understand is - if the valve is clogged, why when I turn on the water inlet - it drains great. Is it just the pressure? Does it immediately clog again when I turn off the inlet?

Thank you so much for any help!

 

[KULTULZ]

Is the drain valve the OEM plastic valve or a brass full-flow ball valve?

If the OEM, the sediment(s) may be blocking flow but the pressurization will blow it clear.

 

[and3008]

Yes, it is the plastic. I will attempt to unclog with a coat hanger.

 

[and3008]

The You Tube video I saw about using a coat hanger - the guy was unclogging the "metal" type valve, so I wonder if it's ok to attempt this with the plastic valve?

 

[SHEPLMBR]

Flush it with valve open.

 

[johnjh2o]

Flush it with valve open.

I agree. Just draining the tank doesn't do much flushing the tank with pressure will do a better job

 

[CT-18]

Crack one of the unions on top. I just changed one and it would not drain till i got some air into it. I open the T&P since i was changing the heater. I do not recommend opening the T&P to let air in.

 

[KULTULZ]

The TPRV DEBATE...

Manufacturers recommend the valve be opened during the yearly service. If it is tripped and then leaks when closed, it is fouled and may possibly be non-functional if an emergency situation occurs. It shows that the tank is filled with sediment(s), some settled and some in suspension.

You simply replace the valve and attempt to control sediment build-up (with sediment filter or frequent flushing) to hopefully prevent future fouling.

If on a service call, explain to the customer if checked and it leaks, the valve should be replaced and the cost. It is then left up for the customer to decide and removes any possible liability from you and/or your insurance carrier.

Does that make sense?

 

[johnjh2o]

I have seen many valves fail to close after opening. But have not seen any fail to open because of sediment.

 

[KULTULZ]

I have seen many valves fail to close after opening. But have not seen any fail to open because of sediment.

Good Point... but, the only place you would actually see one (if you could find it) is while standing next to the fire marshal at the scene of a massive explosion...

 

[KULTULZ]

ADDENDUM (Fr. For I Forgot To Add)

ANNUAL OPERATION OF T&P RELIEF VALVES:

WARNING:

Following installation, the valve lever MUST be operated AT LEAST ONCE A YEAR by the water heater owner to ensure that waterways are clear. Certain naturally occurring mineral deposits may adhere to the valve, blocking waterways, rendering it inoperative. When the lever is operated, hot water will discharge if the waterways are clear. PRECAUTIONS MUST BE TAKEN TO AVOID PERSONAL INJURY FROM CONTACT WITH HOT WATER AND TO AVOID PROPERTY DAMAGE. Before operating lever, check to see that a discharge line is connected to this valve, directing the flow of hot water from the valve to a proper place of disposal. If no water flows when the lever is operated, replacement of the valve is required. TURN THE WATER HEATER “OFF” (see your water heater instruction manual) AND CALL A PLUMBER IMMEDIATELY.

REINSPECTION OF T&P RELIEF VALVES:

WARNING:

Temperature and Pressure Relief Valves should be inspected AT LEAST ONCE EVERY THREE YEARS, and replaced, if necessary, by a licensed plumbing contractor or qualified service technician, to ensure that the product has not been affected by corrosive water conditions and to ensure that the valve and discharge line have not been altered or tampered with illegally. Certain naturally occurring conditions may corrode the valve or its components over time, rendering the valve inoperative. Such conditions can only be detected if the valve and its components are physically removed and inspected. Do not attempt to conduct an inspection on your own. Contact your plumbing contractor for a reinspection to assure continuing safety. FAILURE TO REINSPECT THIS VALVE AS DIRECTED COULD RESULT IN UNSAFE TEMPERATURE OR PRESSURE BUILD-UP WHICH CAN RESULT IN SERIOUS INJURY OR DEATH AND/OR SEVERE PROPERTY DAMAGE.

Now manufacturer's suggestions/instructions generally override code (within common sense) in most cases, correct?

... ... sheesh...

Forgot to show source of info...

-Water Safety & Flow Control Support - Helpful Tools and Resources - WATTS-

 

[johnjh2o]

Ask 100 plumbers if they have ever been called out to do this service to a residential water heater. There will be very few that have if any. Of course the manufactures are going say you should. It's called cover your ass.

 

[SHEPLMBR]

Ask 100 plumbers if they have ever been called out to do this service to a residential water heater. There will be very few that have if any. Of course the manufactures are going say you should. It's called cover your ass.

You should for the efficiency. When sludge from hard water and yuckies gather in the bottom it take longer for the water to heat up. Not to mention in an electric one, the elements get eat up.

 

[johnjh2o]

I never said the heater didn't need to be flushed. I disagreed on the method. I feel flushing it is better as apposed to draining it. I also feel that opening the relief valve to test it is just looking for it to leak.

 

[KULTULZ]

Ask 100 plumbers if they have ever been called out to do this service to a residential water heater. There will be very few that have if any. Of course the manufactures are going say you should. It's called cover your ass.

I never said the heater didn't need to be flushed. I disagreed on the method. I feel flushing it is better as apposed to draining it. I also feel that opening the relief valve to test it is just looking for it to leak.

John, just having a discussion here, not trying to break your b@lls.

The reason you seldom see a service call (IMO) is that the consumer is unaware of the need, especially if bad water is present.

If the TPRV becomes encrusted with calcium say, it may freeze (pintle) and not be able to function properly if the need arises. If not rendered frozen the deposit(s) may effect the calibration of the valve leading to early and/or late opening.

The public should be aware of this and the need to service properly and on a schedule. The WH companies most likely love this as they will sell more WH's.